Chapter 15. Securing access to Kafka Secure your Kafka cluster by managing the access a client has to Kafka brokers. A secure connection between Kafka brokers and clients can encompass the following: Encryption for data exchange Authentication to prove identity Authorization to allow or decline actions executed by users In Streams for Apache Kafka, securing a connection involves configuring listeners and user accounts: Listener configuration Use the Kafka resource to configure listeners for client connections to Kafka brokers. Listeners define how clients authenticate, such as using mTLS, SCRAM-SHA-512, OAuth 2.0, or custom authentication methods. To enhance security, configure TLS encryption to secure communication between Kafka brokers and clients. You can further secure TLS-based communication by specifying the supported TLS versions and cipher suites in the Kafka broker configuration. For an added layer of protection, use the Kafka resource to specify authorization methods for the Kafka cluster, such as simple, OAuth 2.0, OPA, or custom authorization. User accounts Set up user accounts and credentials with KafkaUser resources in Streams for Apache Kafka. Users represent your clients and determine how they should authenticate and authorize with the Kafka cluster. The authentication and authorization mechanisms specified in the user configuration must match the Kafka configuration. Additionally, define Access Control Lists (ACLs) to control user access to specific topics and actions for more fine-grained authorization. To further enhance security, specify user quotas to limit client access to Kafka brokers based on byte rates or CPU utilization. You can also add producer or consumer configuration to your clients if you wish to limit the TLS versions and cipher suites they use. The configuration on the clients must only use protocols and cipher suites that are enabled on the broker. Note If you are using an OAuth 2.0 to manage client access, user authentication and authorization credentials are managed through the authorization server. Streams for Apache Kafka operators automate the configuration process and create the certificates required for authentication. The Cluster Operator automatically sets up TLS certificates for data encryption and authentication within your cluster. 15.1. Security options for Kafka Use the Kafka resource to configure the mechanisms used for Kafka authentication and authorization. 15.1.1. Listener authentication Configure client authentication for Kafka brokers when creating listeners. Specify the listener authentication type using the Kafka.spec.kafka.listeners.authentication property in the Kafka resource. For clients inside the OpenShift cluster, you can create plain (without encryption) or tls internal listeners. The internal listener type use a headless service and the DNS names given to the broker pods. As an alternative to the headless service, you can also create a cluster-ip type of internal listener to expose Kafka using per-broker ClusterIP services. For clients outside the OpenShift cluster, you create external listeners and specify a connection mechanism, which can be nodeport , loadbalancer , ingress (Kubernetes only), or route (OpenShift only). For more information on the configuration options for connecting an external client, see Chapter 14, Setting up client access to a Kafka cluster . Supported authentication options: mTLS authentication (only on the listeners with TLS enabled encryption) SCRAM-SHA-512 authentication OAuth 2.0 token-based authentication Custom authentication TLS versions and cipher suites The authentication option you choose depends on how you wish to authenticate client access to Kafka brokers. Note Try exploring the standard authentication options before using custom authentication. Custom authentication allows for any type of Kafka-supported authentication. It can provide more flexibility, but also adds complexity. Figure 15.1. Kafka listener authentication options The listener authentication property is used to specify an authentication mechanism specific to that listener. If no authentication property is specified then the listener does not authenticate clients which connect through that listener. The listener will accept all connections without authentication. Authentication must be configured when using the User Operator to manage KafkaUsers . The following example shows: A plain listener configured for SCRAM-SHA-512 authentication A tls listener with mTLS authentication An external listener with mTLS authentication Each listener is configured with a unique name and port within a Kafka cluster. Important When configuring listeners for client access to brokers, you can use port 9092 or higher (9093, 9094, and so on), but with a few exceptions. The listeners cannot be configured to use the ports reserved for interbroker communication (9090 and 9091), Prometheus metrics (9404), and JMX (Java Management Extensions) monitoring (9999). Example listener authentication configuration apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka metadata: name: my-cluster namespace: myproject spec: kafka: # ... listeners: - name: plain port: 9092 type: internal tls: true authentication: type: scram-sha-512 - name: tls port: 9093 type: internal tls: true authentication: type: tls - name: external3 port: 9094 type: loadbalancer tls: true authentication: type: tls # ... 15.1.1.1. mTLS authentication mTLS authentication is always used for the communication between Kafka brokers and ZooKeeper pods. Streams for Apache Kafka can configure Kafka to use TLS (Transport Layer Security) to provide encrypted communication between Kafka brokers and clients either with or without mutual authentication. For mutual, or two-way, authentication, both the server and the client present certificates. When you configure mTLS authentication, the broker authenticates the client (client authentication) and the client authenticates the broker (server authentication). mTLS listener configuration in the Kafka resource requires the following: tls: true to specify TLS encryption and server authentication authentication.type: tls to specify the client authentication When a Kafka cluster is created by the Cluster Operator, it creates a new secret with the name <cluster_name>-cluster-ca-cert . The secret contains a CA certificate. The CA certificate is in PEM and PKCS #12 format . To verify a Kafka cluster, add the CA certificate to the truststore in your client configuration. To verify a client, add a user certificate and key to the keystore in your client configuration. For more information on configuring a client for mTLS, see Section 15.2.2, "User authentication" . Note TLS authentication is more commonly one-way, with one party authenticating the identity of another. For example, when HTTPS is used between a web browser and a web server, the browser obtains proof of the identity of the web server. 15.1.1.2. SCRAM-SHA-512 authentication SCRAM (Salted Challenge Response Authentication Mechanism) is an authentication protocol that can establish mutual authentication using passwords. Streams for Apache Kafka can configure Kafka to use SASL (Simple Authentication and Security Layer) SCRAM-SHA-512 to provide authentication on both unencrypted and encrypted client connections. When SCRAM-SHA-512 authentication is used with a TLS connection, the TLS protocol provides the encryption, but is not used for authentication. The following properties of SCRAM make it safe to use SCRAM-SHA-512 even on unencrypted connections: The passwords are not sent in the clear over the communication channel. Instead the client and the server are each challenged by the other to offer proof that they know the password of the authenticating user. The server and client each generate a new challenge for each authentication exchange. This means that the exchange is resilient against replay attacks. When KafkaUser.spec.authentication.type is configured with scram-sha-512 the User Operator will generate a random 12-character password consisting of upper and lowercase ASCII letters and numbers. 15.1.1.3. Network policies By default, Streams for Apache Kafka automatically creates a NetworkPolicy resource for every listener that is enabled on a Kafka broker. This NetworkPolicy allows applications to connect to listeners in all namespaces. Use network policies as part of the listener configuration. If you want to restrict access to a listener at the network level to only selected applications or namespaces, use the networkPolicyPeers property. Each listener can have a different networkPolicyPeers configuration . For more information on network policy peers, refer to the NetworkPolicyPeer API reference . If you want to use custom network policies, you can set the STRIMZI_NETWORK_POLICY_GENERATION environment variable to false in the Cluster Operator configuration. For more information, see Section 9.5, "Configuring the Cluster Operator" . Note Your configuration of OpenShift must support ingress NetworkPolicies in order to use network policies in Streams for Apache Kafka. 15.1.1.4. Providing listener certificates You can provide your own server certificates, called Kafka listener certificates , for TLS listeners or external listeners which have TLS encryption enabled. For more information, see Section 15.3.4, "Providing your own Kafka listener certificates for TLS encryption" . Additional resources GenericKafkaListener schema reference 15.1.2. Kafka authorization Configure authorization for Kafka brokers using the Kafka.spec.kafka.authorization property in the Kafka resource. If the authorization property is missing, no authorization is enabled and clients have no restrictions. When enabled, authorization is applied to all enabled listeners. The authorization method is defined in the type field. Supported authorization options: Simple authorization OAuth 2.0 authorization (if you are using OAuth 2.0 token based authentication) Open Policy Agent (OPA) authorization Custom authorization Figure 15.2. Kafka cluster authorization options 15.1.2.1. Super users Super users can access all resources in your Kafka cluster regardless of any access restrictions, and are supported by all authorization mechanisms. To designate super users for a Kafka cluster, add a list of user principals to the superUsers property. If a user uses mTLS authentication, the username is the common name from the TLS certificate subject prefixed with CN= . If you are not using the User Operator and using your own certificates for mTLS, the username is the full certificate subject. A full certificate subject can have the following fields: CN=user,OU=my_ou,O=my_org,L=my_location,ST=my_state,C=my_country_code . Omit any fields that are not present. An example configuration with super users apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka metadata: name: my-cluster namespace: myproject spec: kafka: # ... authorization: type: simple superUsers: - CN=client_1 - user_2 - CN=client_3 - CN=client_4,OU=my_ou,O=my_org,L=my_location,ST=my_state,C=US - CN=client_5,OU=my_ou,O=my_org,C=GB - CN=client_6,O=my_org # ... 15.2. Security options for Kafka clients Use the KafkaUser resource to configure the authentication mechanism, authorization mechanism, and access rights for Kafka clients. In terms of configuring security, clients are represented as users. You can authenticate and authorize user access to Kafka brokers. Authentication permits access, and authorization constrains the access to permissible actions. You can also create super users that have unconstrained access to Kafka brokers. The authentication and authorization mechanisms must match the specification for the listener used to access the Kafka brokers . For more information on configuring a KafkaUser resource to access Kafka brokers securely, see Section 14.4, "Setting up client access to a Kafka cluster using listeners" . 15.2.1. Identifying a Kafka cluster for user handling A KafkaUser resource includes a label that defines the appropriate name of the Kafka cluster (derived from the name of the Kafka resource) to which it belongs. apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster The label is used by the User Operator to identify the KafkaUser resource and create a new user, and also in subsequent handling of the user. If the label does not match the Kafka cluster, the User Operator cannot identify the KafkaUser and the user is not created. If the status of the KafkaUser resource remains empty, check your label. 15.2.2. User authentication Use the KafkaUser custom resource to configure authentication credentials for users (clients) that require access to a Kafka cluster. Configure the credentials using the authentication property in KafkaUser.spec . By specifying a type , you control what credentials are generated. Supported authentication types: tls for mTLS authentication tls-external for mTLS authentication using external certificates scram-sha-512 for SCRAM-SHA-512 authentication If tls or scram-sha-512 is specified, the User Operator creates authentication credentials when it creates the user. If tls-external is specified, the user still uses mTLS, but no authentication credentials are created. Use this option when you're providing your own certificates. When no authentication type is specified, the User Operator does not create the user or its credentials. You can use tls-external to authenticate with mTLS using a certificate issued outside the User Operator. The User Operator does not generate a TLS certificate or a secret. You can still manage ACL rules and quotas through the User Operator in the same way as when you're using the tls mechanism. This means that you use the CN= USER-NAME format when specifying ACL rules and quotas. USER-NAME is the common name given in a TLS certificate. 15.2.2.1. mTLS authentication To use mTLS authentication, you set the type field in the KafkaUser resource to tls . Example user with mTLS authentication enabled apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: authentication: type: tls # ... The authentication type must match the equivalent configuration for the Kafka listener used to access the Kafka cluster. When the user is created by the User Operator, it creates a new secret with the same name as the KafkaUser resource. The secret contains a private and public key for mTLS. The public key is contained in a user certificate, which is signed by a clients CA (certificate authority) when it is created. All keys are in X.509 format. Note If you are using the clients CA generated by the Cluster Operator, the user certificates generated by the User Operator are also renewed when the clients CA is renewed by the Cluster Operator. The user secret provides keys and certificates in PEM and PKCS #12 formats . Example secret with user credentials apiVersion: v1 kind: Secret metadata: name: my-user labels: strimzi.io/kind: KafkaUser strimzi.io/cluster: my-cluster type: Opaque data: ca.crt: <public_key> # Public key of the clients CA user.crt: <user_certificate> # Public key of the user user.key: <user_private_key> # Private key of the user user.p12: <store> # PKCS #12 store for user certificates and keys user.password: <password_for_store> # Protects the PKCS #12 store When you configure a client, you specify the following: Truststore properties for the public cluster CA certificate to verify the identity of the Kafka cluster Keystore properties for the user authentication credentials to verify the client The configuration depends on the file format (PEM or PKCS #12). This example uses PKCS #12 stores, and the passwords required to access the credentials in the stores. Example client configuration using mTLS in PKCS #12 format bootstrap.servers= <kafka_cluster_name> -kafka-bootstrap:9093 1 security.protocol=SSL 2 ssl.truststore.location=/tmp/ca.p12 3 ssl.truststore.password= <truststore_password> 4 ssl.keystore.location=/tmp/user.p12 5 ssl.keystore.password= <keystore_password> 6 1 The bootstrap server address to connect to the Kafka cluster. 2 The security protocol option when using TLS for encryption. 3 The truststore location contains the public key certificate ( ca.p12 ) for the Kafka cluster. A cluster CA certificate and password is generated by the Cluster Operator in the <cluster_name>-cluster-ca-cert secret when the Kafka cluster is created. 4 The password ( ca.password ) for accessing the truststore. 5 The keystore location contains the public key certificate ( user.p12 ) for the Kafka user. 6 The password ( user.password ) for accessing the keystore. 15.2.2.2. mTLS authentication using a certificate issued outside the User Operator To use mTLS authentication using a certificate issued outside the User Operator, you set the type field in the KafkaUser resource to tls-external . A secret and credentials are not created for the user. Example user with mTLS authentication that uses a certificate issued outside the User Operator apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: authentication: type: tls-external # ... 15.2.2.3. SCRAM-SHA-512 authentication To use the SCRAM-SHA-512 authentication mechanism, you set the type field in the KafkaUser resource to scram-sha-512 . Example user with SCRAM-SHA-512 authentication enabled apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: authentication: type: scram-sha-512 # ... When the user is created by the User Operator, it creates a new secret with the same name as the KafkaUser resource. The secret contains the generated password in the password key, which is encoded with base64. In order to use the password, it must be decoded. Example secret with user credentials apiVersion: v1 kind: Secret metadata: name: my-user labels: strimzi.io/kind: KafkaUser strimzi.io/cluster: my-cluster type: Opaque data: password: Z2VuZXJhdGVkcGFzc3dvcmQ= 1 sasl.jaas.config: b3JnLmFwYWNoZS5rYWZrYS5jb21tb24uc2VjdXJpdHkuc2NyYW0uU2NyYW1Mb2dpbk1vZHVsZSByZXF1aXJlZCB1c2VybmFtZT0ibXktdXNlciIgcGFzc3dvcmQ9ImdlbmVyYXRlZHBhc3N3b3JkIjsK 2 1 The generated password, base64 encoded. 2 The JAAS configuration string for SASL SCRAM-SHA-512 authentication, base64 encoded. Decoding the generated password: 15.2.2.3.1. Custom password configuration When a user is created, Streams for Apache Kafka generates a random password. You can use your own password instead of the one generated by Streams for Apache Kafka. To do so, create a secret with the password and reference it in the KafkaUser resource. Example user with a password set for SCRAM-SHA-512 authentication apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: authentication: type: scram-sha-512 password: valueFrom: secretKeyRef: name: my-secret 1 key: my-password 2 # ... 1 The name of the secret containing the predefined password. 2 The key for the password stored inside the secret. 15.2.3. User authorization Use the KafkaUser custom resource to configure authorization rules for users (clients) that require access to a Kafka cluster. Configure the rules using the authorization property in KafkaUser.spec . By specifying a type , you control what rules are used. To use simple authorization, you set the type property to simple in KafkaUser.spec.authorization . The simple authorization uses the Kafka Admin API to manage the ACL rules inside your Kafka cluster. Whether ACL management in the User Operator is enabled or not depends on your authorization configuration in the Kafka cluster. For simple authorization, ACL management is always enabled. For OPA authorization, ACL management is always disabled. Authorization rules are configured in the OPA server. For Red Hat Single Sign-On authorization, you can manage the ACL rules directly in Red Hat Single Sign-On. You can also delegate authorization to the simple authorizer as a fallback option in the configuration. When delegation to the simple authorizer is enabled, the User Operator will enable management of ACL rules as well. For custom authorization using a custom authorization plugin, use the supportsAdminApi property in the .spec.kafka.authorization configuration of the Kafka custom resource to enable or disable the support. Authorization is cluster-wide. The authorization type must match the equivalent configuration in the Kafka custom resource. If ACL management is not enabled, Streams for Apache Kafka rejects a resource if it contains any ACL rules. If you're using a standalone deployment of the User Operator, ACL management is enabled by default. You can disable it using the STRIMZI_ACLS_ADMIN_API_SUPPORTED environment variable. If no authorization is specified, the User Operator does not provision any access rights for the user. Whether such a KafkaUser can still access resources depends on the authorizer being used. For example, for simple authorization, this is determined by the allow.everyone.if.no.acl.found configuration in the Kafka cluster. 15.2.3.1. ACL rules simple authorization uses ACL rules to manage access to Kafka brokers. ACL rules grant access rights to the user, which you specify in the acls property. For more information about the AclRule object, see the AclRule schema reference . 15.2.3.2. Super user access to Kafka brokers If a user is added to a list of super users in a Kafka broker configuration, the user is allowed unlimited access to the cluster regardless of any authorization constraints defined in ACLs in KafkaUser . For more information on configuring super user access to brokers, see Kafka authorization . 15.2.3.3. User quotas You can configure the spec for the KafkaUser resource to enforce quotas so that a user does not exceed a configured level of access to Kafka brokers. You can set size-based network usage and time-based CPU utilization thresholds. You can also add a partition mutation quota to control the rate at which requests to change partitions are accepted for user requests. An example KafkaUser with user quotas apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: # ... quotas: producerByteRate: 1048576 1 consumerByteRate: 2097152 2 requestPercentage: 55 3 controllerMutationRate: 10 4 1 Byte-per-second quota on the amount of data the user can push to a Kafka broker 2 Byte-per-second quota on the amount of data the user can fetch from a Kafka broker 3 CPU utilization limit as a percentage of time for a client group 4 Number of concurrent partition creation and deletion operations (mutations) allowed per second For more information on these properties, see the KafkaUserQuotas schema reference . 15.3. Securing access to Kafka brokers To establish secure access to Kafka brokers, you configure and apply: A Kafka resource to: Create listeners with a specified authentication type Configure authorization for the whole Kafka cluster A KafkaUser resource to access the Kafka brokers securely through the listeners Configure the Kafka resource to set up: Listener authentication Network policies that restrict access to Kafka listeners Kafka authorization Super users for unconstrained access to brokers Authentication is configured independently for each listener. Authorization is always configured for the whole Kafka cluster. The Cluster Operator creates the listeners and sets up the cluster and client certificate authority (CA) certificates to enable authentication within the Kafka cluster. You can replace the certificates generated by the Cluster Operator by installing your own certificates . You can also provide your own server certificates and private keys for any listener with TLS encryption enabled. These user-provided certificates are called Kafka listener certificates . Providing Kafka listener certificates allows you to leverage existing security infrastructure, such as your organization's private CA or a public CA. Kafka clients will need to trust the CA which was used to sign the listener certificate. You must manually renew Kafka listener certificates when needed. Certificates are available in PKCS #12 format (.p12) and PEM (.crt) formats. Use KafkaUser to enable the authentication and authorization mechanisms that a specific client uses to access Kafka. Configure the KafkaUser resource to set up: Authentication to match the enabled listener authentication Authorization to match the enabled Kafka authorization Quotas to control the use of resources by clients The User Operator creates the user representing the client and the security credentials used for client authentication, based on the chosen authentication type. Refer to the schema reference for more information on access configuration properties: Kafka schema reference KafkaUser schema reference GenericKafkaListener schema reference 15.3.1. Securing Kafka brokers This procedure shows the steps involved in securing Kafka brokers when running Streams for Apache Kafka. The security implemented for Kafka brokers must be compatible with the security implemented for the clients requiring access. Kafka.spec.kafka.listeners[*].authentication matches KafkaUser.spec.authentication Kafka.spec.kafka.authorization matches KafkaUser.spec.authorization The steps show the configuration for simple authorization and a listener using mTLS authentication. For more information on listener configuration, see the GenericKafkaListener schema reference . Alternatively, you can use SCRAM-SHA or OAuth 2.0 for listener authentication , and OAuth 2.0 or OPA for Kafka authorization . Procedure Configure the Kafka resource. Configure the authorization property for authorization. Configure the listeners property to create a listener with authentication. For example: apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka spec: kafka: # ... authorization: 1 type: simple superUsers: 2 - CN=client_1 - user_2 - CN=client_3 listeners: - name: tls port: 9093 type: internal tls: true authentication: type: tls 3 # ... zookeeper: # ... 1 Authorization enables simple authorization on the Kafka broker using the AclAuthorizer and StandardAuthorizer Kafka plugins . 2 List of user principals with unlimited access to Kafka. CN is the common name from the client certificate when mTLS authentication is used. 3 Listener authentication mechanisms may be configured for each listener, and specified as mTLS, SCRAM-SHA-512, or token-based OAuth 2.0 . If you are configuring an external listener, the configuration is dependent on the chosen connection mechanism. Create or update the Kafka resource. oc apply -f <kafka_configuration_file> The Kafka cluster is configured with a Kafka broker listener using mTLS authentication. A service is created for each Kafka broker pod. A service is created to serve as the bootstrap address for connection to the Kafka cluster. The cluster CA certificate to verify the identity of the kafka brokers is also created in the secret <cluster_name> -cluster-ca-cert . 15.3.2. Securing user access to Kafka Create or modify a KafkaUser to represent a client that requires secure access to the Kafka cluster. When you configure the KafkaUser authentication and authorization mechanisms, ensure they match the equivalent Kafka configuration: KafkaUser.spec.authentication matches Kafka.spec.kafka.listeners[*].authentication KafkaUser.spec.authorization matches Kafka.spec.kafka.authorization This procedure shows how a user is created with mTLS authentication. You can also create a user with SCRAM-SHA authentication. The authentication required depends on the type of authentication configured for the Kafka broker listener . Note Authentication between Kafka users and Kafka brokers depends on the authentication settings for each. For example, it is not possible to authenticate a user with mTLS if it is not also enabled in the Kafka configuration. Prerequisites A running Kafka cluster configured with a Kafka broker listener using mTLS authentication and TLS encryption . A running User Operator (typically deployed with the Entity Operator). The authentication type in KafkaUser should match the authentication configured in Kafka brokers. Procedure Configure the KafkaUser resource. For example: apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: authentication: 1 type: tls authorization: type: simple 2 acls: - resource: type: topic name: my-topic patternType: literal operations: - Describe - Read - resource: type: group name: my-group patternType: literal operations: - Read 1 User authentication mechanism, defined as mutual tls or scram-sha-512 . 2 Simple authorization, which requires an accompanying list of ACL rules. Create or update the KafkaUser resource. oc apply -f <user_config_file> The user is created, as well as a Secret with the same name as the KafkaUser resource. The Secret contains a private and public key for mTLS authentication. For information on configuring a Kafka client with properties for secure connection to Kafka brokers, see Section 14.4, "Setting up client access to a Kafka cluster using listeners" . 15.3.3. Restricting access to Kafka listeners using network policies You can restrict access to a listener to only selected applications by using the networkPolicyPeers property. Prerequisites An OpenShift cluster with support for Ingress NetworkPolicies. The Cluster Operator is running. Procedure Open the Kafka resource. In the networkPolicyPeers property, define the application pods or namespaces that will be allowed to access the Kafka cluster. For example, to configure a tls listener to allow connections only from application pods with the label app set to kafka-client : apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka spec: kafka: # ... listeners: - name: tls port: 9093 type: internal tls: true authentication: type: tls networkPolicyPeers: - podSelector: matchLabels: app: kafka-client # ... zookeeper: # ... Create or update the resource. Use oc apply : oc apply -f your-file Additional resources networkPolicyPeers configuration NetworkPolicyPeer API reference 15.3.4. Providing your own Kafka listener certificates for TLS encryption Listeners provide client access to Kafka brokers. Configure listeners in the Kafka resource, including the configuration required for client access using TLS. By default, the listeners use certificates signed by the internal CA (certificate authority) certificates generated by Streams for Apache Kafka. A CA certificate is generated by the Cluster Operator when it creates a Kafka cluster. When you configure a client for TLS, you add the CA certificate to its truststore configuration to verify the Kafka cluster. You can also install and use your own CA certificates . Or you can configure a listener using brokerCertChainAndKey properties and use a custom server certificate. The brokerCertChainAndKey properties allow you to access Kafka brokers using your own custom certificates at the listener-level. You create a secret with your own private key and server certificate, then specify the key and certificate in the listener's brokerCertChainAndKey configuration. You can use a certificate signed by a public (external) CA or a private CA. If signed by a public CA, you usually won't need to add it to a client's truststore configuration. Custom certificates are not managed by Streams for Apache Kafka, so you need to renew them manually. Note Listener certificates are used for TLS encryption and server authentication only. They are not used for TLS client authentication. If you want to use your own certificate for TLS client authentication as well, you must install and use your own clients CA . Prerequisites The Cluster Operator is running. Each listener requires the following: A compatible server certificate signed by an external CA. (Provide an X.509 certificate in PEM format.) You can use one listener certificate for multiple listeners. Subject Alternative Names (SANs) are specified in the certificate for each listener. For more information, see Section 15.3.5, "Alternative subjects in server certificates for Kafka listeners" . If you are not using a self-signed certificate, you can provide a certificate that includes the whole CA chain in the certificate. You can only use the brokerCertChainAndKey properties if TLS encryption ( tls: true ) is configured for the listener. Note Streams for Apache Kafka does not support the use of encrypted private keys for TLS. The private key stored in the secret must be unencrypted for this to work. Procedure Create a Secret containing your private key and server certificate: oc create secret generic my-secret --from-file= my-listener-key.key --from-file= my-listener-certificate.crt Edit the Kafka resource for your cluster. Configure the listener to use your Secret , certificate file, and private key file in the configuration.brokerCertChainAndKey property. Example configuration for a loadbalancer external listener with TLS encryption enabled # ... listeners: - name: plain port: 9092 type: internal tls: false - name: external3 port: 9094 type: loadbalancer tls: true configuration: brokerCertChainAndKey: secretName: my-secret certificate: my-listener-certificate.crt key: my-listener-key.key # ... Example configuration for a TLS listener # ... listeners: - name: plain port: 9092 type: internal tls: false - name: tls port: 9093 type: internal tls: true configuration: brokerCertChainAndKey: secretName: my-secret certificate: my-listener-certificate.crt key: my-listener-key.key # ... Apply the new configuration to create or update the resource: oc apply -f kafka.yaml The Cluster Operator starts a rolling update of the Kafka cluster, which updates the configuration of the listeners. Note A rolling update is also started if you update a Kafka listener certificate in a Secret that is already used by a listener. 15.3.5. Alternative subjects in server certificates for Kafka listeners In order to use TLS hostname verification with your own Kafka listener certificates , you must use the correct Subject Alternative Names (SANs) for each listener. The certificate SANs must specify hostnames for the following: All of the Kafka brokers in your cluster The Kafka cluster bootstrap service You can use wildcard certificates if they are supported by your CA. 15.3.5.1. Examples of SANs for internal listeners Use the following examples to help you specify hostnames of the SANs in your certificates for your internal listeners. Replace <cluster-name> with the name of the Kafka cluster and <namespace> with the OpenShift namespace where the cluster is running. Wildcards example for a type: internal listener //Kafka brokers *. <cluster-name> -kafka-brokers *. <cluster-name> -kafka-brokers. <namespace> .svc // Bootstrap service <cluster-name> -kafka-bootstrap <cluster-name> -kafka-bootstrap. <namespace> .svc Non-wildcards example for a type: internal listener // Kafka brokers <cluster-name> -kafka-0. <cluster-name> -kafka-brokers <cluster-name> -kafka-0. <cluster-name> -kafka-brokers. <namespace> .svc <cluster-name> -kafka-1. <cluster-name> -kafka-brokers <cluster-name> -kafka-1. <cluster-name> -kafka-brokers. <namespace> .svc # ... // Bootstrap service <cluster-name> -kafka-bootstrap <cluster-name> -kafka-bootstrap. <namespace> .svc Non-wildcards example for a type: cluster-ip listener // Kafka brokers <cluster-name> -kafka- <listener-name> -0 <cluster-name> -kafka- <listener-name> -0. <namespace> .svc <cluster-name> -kafka- <listener-name> -1 <cluster-name> -kafka- <listener-name> -1. <namespace> .svc # ... // Bootstrap service <cluster-name> -kafka- <listener-name> -bootstrap <cluster-name> -kafka- <listener-name> -bootstrap. <namespace> .svc 15.3.5.2. Examples of SANs for external listeners For external listeners which have TLS encryption enabled, the hostnames you need to specify in certificates depends on the external listener type . Table 15.1. SANs for each type of external listener External listener type In the SANs, specify... ingress Addresses of all Kafka broker Ingress resources and the address of the bootstrap Ingress . You can use a matching wildcard name. route Addresses of all Kafka broker Routes and the address of the bootstrap Route . You can use a matching wildcard name. loadbalancer Addresses of all Kafka broker loadbalancers and the bootstrap loadbalancer address. You can use a matching wildcard name. nodeport Addresses of all OpenShift worker nodes that the Kafka broker pods might be scheduled to. You can use a matching wildcard name. Additional resources Section 15.3.4, "Providing your own Kafka listener certificates for TLS encryption" 15.4. Using OAuth 2.0 token-based authentication Streams for Apache Kafka supports the use of OAuth 2.0 authentication using the OAUTHBEARER and PLAIN mechanisms. OAuth 2.0 enables standardized token-based authentication and authorization between applications, using a central authorization server to issue tokens that grant limited access to resources. You can configure OAuth 2.0 authentication, then OAuth 2.0 authorization . Kafka brokers and clients both need to be configured to use OAuth 2.0. OAuth 2.0 authentication can also be used in conjunction with simple or OPA-based Kafka authorization . Using OAuth 2.0 token-based authentication, application clients can access resources on application servers (called resource servers ) without exposing account credentials. The application client passes an access token as a means of authenticating, which application servers can also use to determine the level of access to grant. The authorization server handles the granting of access and inquiries about access. In the context of Streams for Apache Kafka: Kafka brokers act as OAuth 2.0 resource servers Kafka clients act as OAuth 2.0 application clients Kafka clients authenticate to Kafka brokers. The brokers and clients communicate with the OAuth 2.0 authorization server, as necessary, to obtain or validate access tokens. For a deployment of Streams for Apache Kafka, OAuth 2.0 integration provides: Server-side OAuth 2.0 support for Kafka brokers Client-side OAuth 2.0 support for Kafka MirrorMaker, Kafka Connect and the Kafka Bridge 15.4.1. OAuth 2.0 authentication mechanisms Streams for Apache Kafka supports the OAUTHBEARER and PLAIN mechanisms for OAuth 2.0 authentication. Both mechanisms allow Kafka clients to establish authenticated sessions with Kafka brokers. The authentication flow between clients, the authorization server, and Kafka brokers is different for each mechanism. We recommend that you configure clients to use OAUTHBEARER whenever possible. OAUTHBEARER provides a higher level of security than PLAIN because client credentials are never shared with Kafka brokers. Consider using PLAIN only with Kafka clients that do not support OAUTHBEARER. You configure Kafka broker listeners to use OAuth 2.0 authentication for connecting clients. If necessary, you can use the OAUTHBEARER and PLAIN mechanisms on the same oauth listener. The properties to support each mechanism must be explicitly specified in the oauth listener configuration. OAUTHBEARER overview OAUTHBEARER is automatically enabled in the oauth listener configuration for the Kafka broker. You can set the enableOauthBearer property to true , though this is not required. # ... authentication: type: oauth # ... enableOauthBearer: true Many Kafka client tools use libraries that provide basic support for OAUTHBEARER at the protocol level. To support application development, Streams for Apache Kafka provides an OAuth callback handler for the upstream Kafka Client Java libraries (but not for other libraries). Therefore, you do not need to write your own callback handlers. An application client can use the callback handler to provide the access token. Clients written in other languages, such as Go, must use custom code to connect to the authorization server and obtain the access token. With OAUTHBEARER, the client initiates a session with the Kafka broker for credentials exchange, where credentials take the form of a bearer token provided by the callback handler. Using the callbacks, you can configure token provision in one of three ways: Client ID and Secret (by using the OAuth 2.0 client credentials mechanism) A long-lived access token, obtained manually at configuration time A long-lived refresh token, obtained manually at configuration time Note OAUTHBEARER authentication can only be used by Kafka clients that support the OAUTHBEARER mechanism at the protocol level. PLAIN overview To use PLAIN, you must enable it in the oauth listener configuration for the Kafka broker. In the following example, PLAIN is enabled in addition to OAUTHBEARER, which is enabled by default. If you want to use PLAIN only, you can disable OAUTHBEARER by setting enableOauthBearer to false . # ... authentication: type: oauth # ... enablePlain: true tokenEndpointUri: https:// OAUTH-SERVER-ADDRESS /auth/realms/external/protocol/openid-connect/token PLAIN is a simple authentication mechanism used by all Kafka client tools. To enable PLAIN to be used with OAuth 2.0 authentication, Streams for Apache Kafka provides OAuth 2.0 over PLAIN server-side callbacks. With the Streams for Apache Kafka implementation of PLAIN, the client credentials are not stored in ZooKeeper. Instead, client credentials are handled centrally behind a compliant authorization server, similar to when OAUTHBEARER authentication is used. When used with the OAuth 2.0 over PLAIN callbacks, Kafka clients authenticate with Kafka brokers using either of the following methods: Client ID and secret (by using the OAuth 2.0 client credentials mechanism) A long-lived access token, obtained manually at configuration time For both methods, the client must provide the PLAIN username and password properties to pass credentials to the Kafka broker. The client uses these properties to pass a client ID and secret or username and access token. Client IDs and secrets are used to obtain access tokens. Access tokens are passed as password property values. You pass the access token with or without an USDaccessToken: prefix. If you configure a token endpoint ( tokenEndpointUri ) in the listener configuration, you need the prefix. If you don't configure a token endpoint ( tokenEndpointUri ) in the listener configuration, you don't need the prefix. The Kafka broker interprets the password as a raw access token. If the password is set as the access token, the username must be set to the same principal name that the Kafka broker obtains from the access token. You can specify username extraction options in your listener using the userNameClaim , fallbackUserNameClaim , fallbackUsernamePrefix , and userInfoEndpointUri properties. The username extraction process also depends on your authorization server; in particular, how it maps client IDs to account names. Note OAuth over PLAIN does not support password grant mechanism. You can only 'proxy' through SASL PLAIN mechanism the client credentials (clientId + secret) or the access token as described above. Additional resources Section 15.4.6.2, "Configuring OAuth 2.0 support for Kafka brokers" 15.4.2. OAuth 2.0 Kafka broker configuration Kafka broker configuration for OAuth 2.0 involves: Creating the OAuth 2.0 client in the authorization server Configuring OAuth 2.0 authentication in the Kafka custom resource Note In relation to the authorization server, Kafka brokers and Kafka clients are both regarded as OAuth 2.0 clients. 15.4.2.1. OAuth 2.0 client configuration on an authorization server To configure a Kafka broker to validate the token received during session initiation, the recommended approach is to create an OAuth 2.0 client definition in an authorization server, configured as confidential , with the following client credentials enabled: Client ID of kafka (for example) Client ID and Secret as the authentication mechanism Note You only need to use a client ID and secret when using a non-public introspection endpoint of the authorization server. The credentials are not typically required when using public authorization server endpoints, as with fast local JWT token validation. 15.4.2.2. OAuth 2.0 authentication configuration in the Kafka cluster To use OAuth 2.0 authentication in the Kafka cluster, you specify, for example, a tls listener configuration for your Kafka cluster custom resource with the authentication method oauth : Assigining the authentication method type for OAuth 2.0 apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka spec: kafka: # ... listeners: - name: tls port: 9093 type: internal tls: true authentication: type: oauth #... You can configure OAuth 2.0 authentication in your listeners. We recommend using OAuth 2.0 authentication together with TLS encryption ( tls: true ). Without encryption, the connection is vulnerable to network eavesdropping and unauthorized access through token theft. You configure an external listener with type: oauth for a secure transport layer to communicate with the client. Using OAuth 2.0 with an external listener # ... listeners: - name: external3 port: 9094 type: loadbalancer tls: true authentication: type: oauth #... The tls property is false by default, so it must be enabled. When you have defined the type of authentication as OAuth 2.0, you add configuration based on the type of validation, either as fast local JWT validation or token validation using an introspection endpoint . The procedure to configure OAuth 2.0 for listeners, with descriptions and examples, is described in Configuring OAuth 2.0 support for Kafka brokers . 15.4.2.3. Fast local JWT token validation configuration Fast local JWT token validation checks a JWT token signature locally. The local check ensures that a token: Conforms to type by containing a ( typ ) claim value of Bearer for an access token Is valid (not expired) Has an issuer that matches a validIssuerURI You specify a validIssuerURI attribute when you configure the listener, so that any tokens not issued by the authorization server are rejected. The authorization server does not need to be contacted during fast local JWT token validation. You activate fast local JWT token validation by specifying a jwksEndpointUri attribute, the endpoint exposed by the OAuth 2.0 authorization server. The endpoint contains the public keys used to validate signed JWT tokens, which are sent as credentials by Kafka clients. Note All communication with the authorization server should be performed using TLS encryption. You can configure a certificate truststore as an OpenShift Secret in your Streams for Apache Kafka project namespace, and use a tlsTrustedCertificates attribute to point to the OpenShift Secret containing the truststore file. You might want to configure a userNameClaim to properly extract a username from the JWT token. If required, you can use a JsonPath expression like "['user.info'].['user.id']" to retrieve the username from nested JSON attributes within a token. If you want to use Kafka ACL authorization, you need to identify the user by their username during authentication. (The sub claim in JWT tokens is typically a unique ID, not a username.) Example configuration for fast local JWT token validation apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka spec: kafka: #... listeners: - name: tls port: 9093 type: internal tls: true authentication: type: oauth validIssuerUri: <https://<auth_server_address>/auth/realms/tls> jwksEndpointUri: <https://<auth_server_address>/auth/realms/tls/protocol/openid-connect/certs> userNameClaim: preferred_username maxSecondsWithoutReauthentication: 3600 tlsTrustedCertificates: - secretName: oauth-server-cert certificate: ca.crt #... 15.4.2.4. OAuth 2.0 introspection endpoint configuration Token validation using an OAuth 2.0 introspection endpoint treats a received access token as opaque. The Kafka broker sends an access token to the introspection endpoint, which responds with the token information necessary for validation. Importantly, it returns up-to-date information if the specific access token is valid, and also information about when the token expires. To configure OAuth 2.0 introspection-based validation, you specify an introspectionEndpointUri attribute rather than the jwksEndpointUri attribute specified for fast local JWT token validation. Depending on the authorization server, you typically have to specify a clientId and clientSecret , because the introspection endpoint is usually protected. Example configuration for an introspection endpoint apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka spec: kafka: listeners: - name: tls port: 9093 type: internal tls: true authentication: type: oauth clientId: kafka-broker clientSecret: secretName: my-cluster-oauth key: clientSecret validIssuerUri: <https://<auth_server_-_address>/auth/realms/tls> introspectionEndpointUri: <https://<auth_server_address>/auth/realms/tls/protocol/openid-connect/token/introspect> userNameClaim: preferred_username maxSecondsWithoutReauthentication: 3600 tlsTrustedCertificates: - secretName: oauth-server-cert certificate: ca.crt 15.4.3. Session re-authentication for Kafka brokers You can configure oauth listeners to use Kafka session re-authentication for OAuth 2.0 sessions between Kafka clients and Kafka brokers. This mechanism enforces the expiry of an authenticated session between the client and the broker after a defined period of time. When a session expires, the client immediately starts a new session by reusing the existing connection rather than dropping it. Session re-authentication is disabled by default. To enable it, you set a time value for maxSecondsWithoutReauthentication in the oauth listener configuration. The same property is used to configure session re-authentication for OAUTHBEARER and PLAIN authentication. For an example configuration, see Section 15.4.6.2, "Configuring OAuth 2.0 support for Kafka brokers" . Session re-authentication must be supported by the Kafka client libraries used by the client. Session re-authentication can be used with fast local JWT or introspection endpoint token validation. Client re-authentication When the broker's authenticated session expires, the client must re-authenticate to the existing session by sending a new, valid access token to the broker, without dropping the connection. If token validation is successful, a new client session is started using the existing connection. If the client fails to re-authenticate, the broker will close the connection if further attempts are made to send or receive messages. Java clients that use Kafka client library 2.2 or later automatically re-authenticate if the re-authentication mechanism is enabled on the broker. Session re-authentication also applies to refresh tokens, if used. When the session expires, the client refreshes the access token by using its refresh token. The client then uses the new access token to re-authenticate to the existing session. Session expiry for OAUTHBEARER and PLAIN When session re-authentication is configured, session expiry works differently for OAUTHBEARER and PLAIN authentication. For OAUTHBEARER and PLAIN, using the client ID and secret method: The broker's authenticated session will expire at the configured maxSecondsWithoutReauthentication . The session will expire earlier if the access token expires before the configured time. For PLAIN using the long-lived access token method: The broker's authenticated session will expire at the configured maxSecondsWithoutReauthentication . Re-authentication will fail if the access token expires before the configured time. Although session re-authentication is attempted, PLAIN has no mechanism for refreshing tokens. If maxSecondsWithoutReauthentication is not configured, OAUTHBEARER and PLAIN clients can remain connected to brokers indefinitely, without needing to re-authenticate. Authenticated sessions do not end with access token expiry. However, this can be considered when configuring authorization, for example, by using keycloak authorization or installing a custom authorizer. Additional resources Section 15.4.2, "OAuth 2.0 Kafka broker configuration" Section 15.4.6.2, "Configuring OAuth 2.0 support for Kafka brokers" KafkaListenerAuthenticationOAuth schema reference KIP-368 15.4.4. OAuth 2.0 Kafka client configuration A Kafka client is configured with either: The credentials required to obtain a valid access token from an authorization server (client ID and Secret) A valid long-lived access token or refresh token, obtained using tools provided by an authorization server The only information ever sent to the Kafka broker is an access token. The credentials used to authenticate with the authorization server to obtain the access token are never sent to the broker. When a client obtains an access token, no further communication with the authorization server is needed. The simplest mechanism is authentication with a client ID and Secret. Using a long-lived access token, or a long-lived refresh token, adds more complexity because there is an additional dependency on authorization server tools. Note If you are using long-lived access tokens, you may need to configure the client in the authorization server to increase the maximum lifetime of the token. If the Kafka client is not configured with an access token directly, the client exchanges credentials for an access token during Kafka session initiation by contacting the authorization server. The Kafka client exchanges either: Client ID and Secret Client ID, refresh token, and (optionally) a secret Username and password, with client ID and (optionally) a secret 15.4.5. OAuth 2.0 client authentication flows OAuth 2.0 authentication flows depend on the underlying Kafka client and Kafka broker configuration. The flows must also be supported by the authorization server used. The Kafka broker listener configuration determines how clients authenticate using an access token. The client can pass a client ID and secret to request an access token. If a listener is configured to use PLAIN authentication, the client can authenticate with a client ID and secret or username and access token. These values are passed as the username and password properties of the PLAIN mechanism. Listener configuration supports the following token validation options: You can use fast local token validation based on JWT signature checking and local token introspection, without contacting an authorization server. The authorization server provides a JWKS endpoint with public certificates that are used to validate signatures on the tokens. You can use a call to a token introspection endpoint provided by an authorization server. Each time a new Kafka broker connection is established, the broker passes the access token received from the client to the authorization server. The Kafka broker checks the response to confirm whether or not the token is valid. Note An authorization server might only allow the use of opaque access tokens, which means that local token validation is not possible. Kafka client credentials can also be configured for the following types of authentication: Direct local access using a previously generated long-lived access token Contact with the authorization server for a new access token to be issued (using a client ID and a secret, or a refresh token, or a username and a password) 15.4.5.1. Example client authentication flows using the SASL OAUTHBEARER mechanism You can use the following communication flows for Kafka authentication using the SASL OAUTHBEARER mechanism. Client using client ID and secret, with broker delegating validation to authorization server Client using client ID and secret, with broker performing fast local token validation Client using long-lived access token, with broker delegating validation to authorization server Client using long-lived access token, with broker performing fast local validation Client using client ID and secret, with broker delegating validation to authorization server The Kafka client requests an access token from the authorization server using a client ID and secret, and optionally a refresh token. Alternatively, the client may authenticate using a username and a password. The authorization server generates a new access token. The Kafka client authenticates with the Kafka broker using the SASL OAUTHBEARER mechanism to pass the access token. The Kafka broker validates the access token by calling a token introspection endpoint on the authorization server using its own client ID and secret. A Kafka client session is established if the token is valid. Client using client ID and secret, with broker performing fast local token validation The Kafka client authenticates with the authorization server from the token endpoint, using a client ID and secret, and optionally a refresh token. Alternatively, the client may authenticate using a username and a password. The authorization server generates a new access token. The Kafka client authenticates with the Kafka broker using the SASL OAUTHBEARER mechanism to pass the access token. The Kafka broker validates the access token locally using a JWT token signature check, and local token introspection. Client using long-lived access token, with broker delegating validation to authorization server The Kafka client authenticates with the Kafka broker using the SASL OAUTHBEARER mechanism to pass the long-lived access token. The Kafka broker validates the access token by calling a token introspection endpoint on the authorization server, using its own client ID and secret. A Kafka client session is established if the token is valid. Client using long-lived access token, with broker performing fast local validation The Kafka client authenticates with the Kafka broker using the SASL OAUTHBEARER mechanism to pass the long-lived access token. The Kafka broker validates the access token locally using a JWT token signature check and local token introspection. Warning Fast local JWT token signature validation is suitable only for short-lived tokens as there is no check with the authorization server if a token has been revoked. Token expiration is written into the token, but revocation can happen at any time, so cannot be accounted for without contacting the authorization server. Any issued token would be considered valid until it expires. 15.4.5.2. Example client authentication flows using the SASL PLAIN mechanism You can use the following communication flows for Kafka authentication using the OAuth PLAIN mechanism. Client using a client ID and secret, with the broker obtaining the access token for the client Client using a long-lived access token without a client ID and secret Client using a client ID and secret, with the broker obtaining the access token for the client The Kafka client passes a clientId as a username and a secret as a password. The Kafka broker uses a token endpoint to pass the clientId and secret to the authorization server. The authorization server returns a fresh access token or an error if the client credentials are not valid. The Kafka broker validates the token in one of the following ways: If a token introspection endpoint is specified, the Kafka broker validates the access token by calling the endpoint on the authorization server. A session is established if the token validation is successful. If local token introspection is used, a request is not made to the authorization server. The Kafka broker validates the access token locally using a JWT token signature check. Client using a long-lived access token without a client ID and secret The Kafka client passes a username and password. The password provides the value of an access token that was obtained manually and configured before running the client. The password is passed with or without an USDaccessToken: string prefix depending on whether or not the Kafka broker listener is configured with a token endpoint for authentication. If the token endpoint is configured, the password should be prefixed by USDaccessToken: to let the broker know that the password parameter contains an access token rather than a client secret. The Kafka broker interprets the username as the account username. If the token endpoint is not configured on the Kafka broker listener (enforcing a no-client-credentials mode ), the password should provide the access token without the prefix. The Kafka broker interprets the username as the account username. In this mode, the client doesn't use a client ID and secret, and the password parameter is always interpreted as a raw access token. The Kafka broker validates the token in one of the following ways: If a token introspection endpoint is specified, the Kafka broker validates the access token by calling the endpoint on the authorization server. A session is established if token validation is successful. If local token introspection is used, there is no request made to the authorization server. Kafka broker validates the access token locally using a JWT token signature check. 15.4.6. Configuring OAuth 2.0 authentication OAuth 2.0 is used for interaction between Kafka clients and Streams for Apache Kafka components. In order to use OAuth 2.0 for Streams for Apache Kafka, you must: Deploy an authorization server and configure the deployment to integrate with Streams for Apache Kafka Deploy or update the Kafka cluster with Kafka broker listeners configured to use OAuth 2.0 Update your Java-based Kafka clients to use OAuth 2.0 Update Kafka component clients to use OAuth 2.0 15.4.6.1. Configuring an OAuth 2.0 authorization server This procedure describes in general what you need to do to configure an authorization server for integration with Streams for Apache Kafka. These instructions are not product specific. The steps are dependent on the chosen authorization server. Consult the product documentation for the authorization server for information on how to set up OAuth 2.0 access. Note If you already have an authorization server deployed, you can skip the deployment step and use your current deployment. Procedure Deploy the authorization server to your cluster. Access the CLI or admin console for the authorization server to configure OAuth 2.0 for Streams for Apache Kafka. Now prepare the authorization server to work with Streams for Apache Kafka. Configure a kafka-broker client. Configure clients for each Kafka client component of your application. What to do After deploying and configuring the authorization server, configure the Kafka brokers to use OAuth 2.0 . 15.4.6.2. Configuring OAuth 2.0 support for Kafka brokers This procedure describes how to configure Kafka brokers so that the broker listeners are enabled to use OAuth 2.0 authentication using an authorization server. We advise use of OAuth 2.0 over an encrypted interface through through a listener with tls: true . Plain listeners are not recommended. If the authorization server is using certificates signed by the trusted CA and matching the OAuth 2.0 server hostname, TLS connection works using the default settings. Otherwise, you may need to configure the truststore with proper certificates or disable the certificate hostname validation. When configuring the Kafka broker you have two options for the mechanism used to validate the access token during OAuth 2.0 authentication of the newly connected Kafka client: Configuring fast local JWT token validation Configuring token validation using an introspection endpoint Before you start For more information on the configuration of OAuth 2.0 authentication for Kafka broker listeners, see: KafkaListenerAuthenticationOAuth schema reference OAuth 2.0 authentication mechanisms Prerequisites Streams for Apache Kafka and Kafka are running An OAuth 2.0 authorization server is deployed Procedure Update the Kafka broker configuration ( Kafka.spec.kafka ) of your Kafka resource in an editor. oc edit kafka my-cluster Configure the Kafka broker listeners configuration. The configuration for each type of listener does not have to be the same, as they are independent. The examples here show the configuration options as configured for external listeners. Example 1: Configuring fast local JWT token validation #... - name: external3 port: 9094 type: loadbalancer tls: true authentication: type: oauth 1 validIssuerUri: https://<auth_server_address>/auth/realms/external 2 jwksEndpointUri: https://<auth_server_address>/auth/realms/external/protocol/openid-connect/certs 3 userNameClaim: preferred_username 4 maxSecondsWithoutReauthentication: 3600 5 tlsTrustedCertificates: 6 - secretName: oauth-server-cert certificate: ca.crt disableTlsHostnameVerification: true 7 jwksExpirySeconds: 360 8 jwksRefreshSeconds: 300 9 jwksMinRefreshPauseSeconds: 1 10 1 Listener type set to oauth . 2 URI of the token issuer used for authentication. 3 URI of the JWKS certificate endpoint used for local JWT validation. 4 The token claim (or key) that contains the actual username used to identify the user. Its value depends on the authorization server. If necessary, a JsonPath expression like "['user.info'].['user.id']" can be used to retrieve the username from nested JSON attributes within a token. 5 (Optional) Activates the Kafka re-authentication mechanism that enforces session expiry to the same length of time as the access token. If the specified value is less than the time left for the access token to expire, then the client will have to re-authenticate before the actual token expiry. By default, the session does not expire when the access token expires, and the client does not attempt re-authentication. 6 (Optional) Trusted certificates for TLS connection to the authorization server. 7 (Optional) Disable TLS hostname verification. Default is false . 8 The duration the JWKS certificates are considered valid before they expire. Default is 360 seconds. If you specify a longer time, consider the risk of allowing access to revoked certificates. 9 The period between refreshes of JWKS certificates. The interval must be at least 60 seconds shorter than the expiry interval. Default is 300 seconds. 10 The minimum pause in seconds between consecutive attempts to refresh JWKS public keys. When an unknown signing key is encountered, the JWKS keys refresh is scheduled outside the regular periodic schedule with at least the specified pause since the last refresh attempt. The refreshing of keys follows the rule of exponential backoff, retrying on unsuccessful refreshes with ever increasing pause, until it reaches jwksRefreshSeconds . The default value is 1. Example 2: Configuring token validation using an introspection endpoint - name: external3 port: 9094 type: loadbalancer tls: true authentication: type: oauth validIssuerUri: https://<auth_server_address>/auth/realms/external introspectionEndpointUri: https://<auth_server_address>/auth/realms/external/protocol/openid-connect/token/introspect 1 clientId: kafka-broker 2 clientSecret: 3 secretName: my-cluster-oauth key: clientSecret userNameClaim: preferred_username 4 maxSecondsWithoutReauthentication: 3600 5 1 URI of the token introspection endpoint. 2 Client ID to identify the client. 3 Client Secret and client ID is used for authentication. 4 The token claim (or key) that contains the actual username used to identify the user. Its value depends on the authorization server. If necessary, a JsonPath expression like "['user.info'].['user.id']" can be used to retrieve the username from nested JSON attributes within a token. 5 (Optional) Activates the Kafka re-authentication mechanism that enforces session expiry to the same length of time as the access token. If the specified value is less than the time left for the access token to expire, then the client will have to re-authenticate before the actual token expiry. By default, the session does not expire when the access token expires, and the client does not attempt re-authentication. Depending on how you apply OAuth 2.0 authentication, and the type of authorization server, there are additional (optional) configuration settings you can use: # ... authentication: type: oauth # ... checkIssuer: false 1 checkAudience: true 2 fallbackUserNameClaim: client_id 3 fallbackUserNamePrefix: client-account- 4 validTokenType: bearer 5 userInfoEndpointUri: https://<auth_server_address>/auth/realms/external/protocol/openid-connect/userinfo 6 enableOauthBearer: false 7 enablePlain: true 8 tokenEndpointUri: https://<auth_server_address>/auth/realms/external/protocol/openid-connect/token 9 customClaimCheck: "@.custom == 'custom-value'" 10 clientAudience: audience 11 clientScope: scope 12 connectTimeoutSeconds: 60 13 readTimeoutSeconds: 60 14 httpRetries: 2 15 httpRetryPauseMs: 300 16 groupsClaim: "USD.groups" 17 groupsClaimDelimiter: "," 18 includeAcceptHeader: false 19 1 If your authorization server does not provide an iss claim, it is not possible to perform an issuer check. In this situation, set checkIssuer to false and do not specify a validIssuerUri . Default is true . 2 If your authorization server provides an aud (audience) claim, and you want to enforce an audience check, set checkAudience to true . Audience checks identify the intended recipients of tokens. As a result, the Kafka broker will reject tokens that do not have its clientId in their aud claim. Default is false . 3 An authorization server may not provide a single attribute to identify both regular users and clients. When a client authenticates in its own name, the server might provide a client ID . When a user authenticates using a username and password to obtain a refresh token or an access token, the server might provide a username attribute in addition to a client ID. Use this fallback option to specify the username claim (attribute) to use if a primary user ID attribute is not available. If necessary, a JsonPath expression like "['client.info'].['client.id']" can be used to retrieve the fallback username to retrieve the username from nested JSON attributes within a token. 4 In situations where fallbackUserNameClaim is applicable, it may also be necessary to prevent name collisions between the values of the username claim, and those of the fallback username claim. Consider a situation where a client called producer exists, but also a regular user called producer exists. In order to differentiate between the two, you can use this property to add a prefix to the user ID of the client. 5 (Only applicable when using introspectionEndpointUri ) Depending on the authorization server you are using, the introspection endpoint may or may not return the token type attribute, or it may contain different values. You can specify a valid token type value that the response from the introspection endpoint has to contain. 6 (Only applicable when using introspectionEndpointUri ) The authorization server may be configured or implemented in such a way to not provide any identifiable information in an Introspection Endpoint response. In order to obtain the user ID, you can configure the URI of the userinfo endpoint as a fallback. The userNameClaim , fallbackUserNameClaim , and fallbackUserNamePrefix settings are applied to the response of userinfo endpoint. 7 Set this to false to disable the OAUTHBEARER mechanism on the listener. At least one of PLAIN or OAUTHBEARER has to be enabled. Default is true . 8 Set to true to enable PLAIN authentication on the listener, which is supported for clients on all platforms. 9 Additional configuration for the PLAIN mechanism. If specified, clients can authenticate over PLAIN by passing an access token as the password using an USDaccessToken: prefix. For production, always use https:// urls. 10 Additional custom rules can be imposed on the JWT access token during validation by setting this to a JsonPath filter query. If the access token does not contain the necessary data, it is rejected. When using the introspectionEndpointUri , the custom check is applied to the introspection endpoint response JSON. 11 An audience parameter passed to the token endpoint. An audience is used when obtaining an access token for inter-broker authentication. It is also used in the name of a client for OAuth 2.0 over PLAIN client authentication using a clientId and secret . This only affects the ability to obtain the token, and the content of the token, depending on the authorization server. It does not affect token validation rules by the listener. 12 A scope parameter passed to the token endpoint. A scope is used when obtaining an access token for inter-broker authentication. It is also used in the name of a client for OAuth 2.0 over PLAIN client authentication using a clientId and secret . This only affects the ability to obtain the token, and the content of the token, depending on the authorization server. It does not affect token validation rules by the listener. 13 The connect timeout in seconds when connecting to the authorization server. The default value is 60. 14 The read timeout in seconds when connecting to the authorization server. The default value is 60. 15 The maximum number of times to retry a failed HTTP request to the authorization server. The default value is 0 , meaning that no retries are performed. To use this option effectively, consider reducing the timeout times for the connectTimeoutSeconds and readTimeoutSeconds options. However, note that retries may prevent the current worker thread from being available to other requests, and if too many requests stall, it could make the Kafka broker unresponsive. 16 The time to wait before attempting another retry of a failed HTTP request to the authorization server. By default, this time is set to zero, meaning that no pause is applied. This is because many issues that cause failed requests are per-request network glitches or proxy issues that can be resolved quickly. However, if your authorization server is under stress or experiencing high traffic, you may want to set this option to a value of 100 ms or more to reduce the load on the server and increase the likelihood of successful retries. 17 A JsonPath query that is used to extract groups information from either the JWT token or the introspection endpoint response. This option is not set by default. By configuring this option, a custom authorizer can make authorization decisions based on user groups. 18 A delimiter used to parse groups information when it is returned as a single delimited string. The default value is ',' (comma). 19 Some authorization servers have issues with client sending Accept: application/json header. By setting includeAcceptHeader: false the header will not be sent. Default is true . Save and exit the editor, then wait for rolling updates to complete. Check the update in the logs or by watching the pod state transitions: oc logs -f USD{POD_NAME} -c USD{CONTAINER_NAME} oc get pod -w The rolling update configures the brokers to use OAuth 2.0 authentication. What to do Configure your Kafka clients to use OAuth 2.0 15.4.6.3. Configuring Kafka Java clients to use OAuth 2.0 Configure Kafka producer and consumer APIs to use OAuth 2.0 for interaction with Kafka brokers. Add a callback plugin to your client pom.xml file, then configure your client for OAuth 2.0. Specify the following in your client configuration: A SASL (Simple Authentication and Security Layer) security protocol: SASL_SSL for authentication over TLS encrypted connections SASL_PLAINTEXT for authentication over unencrypted connections Use SASL_SSL for production and SASL_PLAINTEXT for local development only. When using SASL_SSL , additional ssl.truststore configuration is needed. The truststore configuration is required for secure connection ( https:// ) to the OAuth 2.0 authorization server. To verify the OAuth 2.0 authorization server, add the CA certificate for the authorization server to the truststore in your client configuration. You can configure a truststore in PEM or PKCS #12 format. A Kafka SASL mechanism: OAUTHBEARER for credentials exchange using a bearer token PLAIN to pass client credentials (clientId + secret) or an access token A JAAS (Java Authentication and Authorization Service) module that implements the SASL mechanism: org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule implements the OAuthbearer mechanism org.apache.kafka.common.security.plain.PlainLoginModule implements the plain mechanism To be able to use the OAuthbearer mechanism, you must also add the custom io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler class as the callback handler. JaasClientOauthLoginCallbackHandler handles OAuth callbacks to the authorization server for access tokens during client login. This enables automatic token renewal, ensuring continuous authentication without user intervention. Additionally, it handles login credentials for clients using the OAuth 2.0 password grant method. SASL authentication properties, which support the following authentication methods: OAuth 2.0 client credentials OAuth 2.0 password grant (deprecated) Access token Refresh token Add the SASL authentication properties as JAAS configuration ( sasl.jaas.config and sasl.login.callback.handler.class ). How you configure the authentication properties depends on the authentication method you are using to access the OAuth 2.0 authorization server. In this procedure, the properties are specified in a properties file, then loaded into the client configuration. Note You can also specify authentication properties as environment variables, or as Java system properties. For Java system properties, you can set them using setProperty and pass them on the command line using the -D option. Prerequisites Streams for Apache Kafka and Kafka are running An OAuth 2.0 authorization server is deployed and configured for OAuth access to Kafka brokers Kafka brokers are configured for OAuth 2.0 Procedure Add the client library with OAuth 2.0 support to the pom.xml file for the Kafka client: <dependency> <groupId>io.strimzi</groupId> <artifactId>kafka-oauth-client</artifactId> <version>0.15.0.redhat-00007</version> </dependency> Configure the client properties by specifying the following configuration in a properties file: The security protocol The SASL mechanism The JAAS module and authentication properties according to the method being used For example, we can add the following to a client.properties file: Client credentials mechanism properties security.protocol=SASL_SSL 1 sasl.mechanism=OAUTHBEARER 2 ssl.truststore.location=/tmp/truststore.p12 3 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required \ oauth.token.endpoint.uri="<token_endpoint_url>" \ 4 oauth.client.id="<client_id>" \ 5 oauth.client.secret="<client_secret>" \ 6 oauth.ssl.truststore.location="/tmp/oauth-truststore.p12" \ 7 oauth.ssl.truststore.password="USDSTOREPASS" \ 8 oauth.ssl.truststore.type="PKCS12" \ 9 oauth.scope="<scope>" \ 10 oauth.audience="<audience>" ; 11 sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler 1 SASL_SSL security protocol for TLS-encrypted connections. Use SASL_PLAINTEXT over unencrypted connections for local development only. 2 The SASL mechanism specified as OAUTHBEARER or PLAIN . 3 The truststore configuration for secure access to the Kafka cluster. 4 URI of the authorization server token endpoint. 5 Client ID, which is the name used when creating the client in the authorization server. 6 Client secret created when creating the client in the authorization server. 7 The location contains the public key certificate ( truststore.p12 ) for the authorization server. 8 The password for accessing the truststore. 9 The truststore type. 10 (Optional) The scope for requesting the token from the token endpoint. An authorization server may require a client to specify the scope. 11 (Optional) The audience for requesting the token from the token endpoint. An authorization server may require a client to specify the audience. Password grants mechanism properties security.protocol=SASL_SSL sasl.mechanism=OAUTHBEARER ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required \ oauth.token.endpoint.uri="<token_endpoint_url>" \ oauth.client.id="<client_id>" \ 1 oauth.client.secret="<client_secret>" \ 2 oauth.password.grant.username="<username>" \ 3 oauth.password.grant.password="<password>" \ 4 oauth.ssl.truststore.location="/tmp/oauth-truststore.p12" \ oauth.ssl.truststore.password="USDSTOREPASS" \ oauth.ssl.truststore.type="PKCS12" \ oauth.scope="<scope>" \ oauth.audience="<audience>" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler 1 Client ID, which is the name used when creating the client in the authorization server. 2 (Optional) Client secret created when creating the client in the authorization server. 3 Username for password grant authentication. OAuth password grant configuration (username and password) uses the OAuth 2.0 password grant method. To use password grants, create a user account for a client on your authorization server with limited permissions. The account should act like a service account. Use in environments where user accounts are required for authentication, but consider using a refresh token first. 4 Password for password grant authentication. Note SASL PLAIN does not support passing a username and password (password grants) using the OAuth 2.0 password grant method. Access token properties security.protocol=SASL_SSL sasl.mechanism=OAUTHBEARER ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required \ oauth.token.endpoint.uri="<token_endpoint_url>" \ oauth.access.token="<access_token>" \ 1 oauth.ssl.truststore.location="/tmp/oauth-truststore.p12" \ oauth.ssl.truststore.password="USDSTOREPASS" \ oauth.ssl.truststore.type="PKCS12" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler 1 Long-lived access token for Kafka clients. Refresh token properties security.protocol=SASL_SSL sasl.mechanism=OAUTHBEARER ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required \ oauth.token.endpoint.uri="<token_endpoint_url>" \ oauth.client.id="<client_id>" \ 1 oauth.client.secret="<client_secret>" \ 2 oauth.refresh.token="<refresh_token>" \ 3 oauth.ssl.truststore.location="/tmp/oauth-truststore.p12" \ oauth.ssl.truststore.password="USDSTOREPASS" \ oauth.ssl.truststore.type="PKCS12" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler 1 Client ID, which is the name used when creating the client in the authorization server. 2 (Optional) Client secret created when creating the client in the authorization server. 3 Long-lived refresh token for Kafka clients. Input the client properties for OAUTH 2.0 authentication into the Java client code. Example showing input of client properties Properties props = new Properties(); try (FileReader reader = new FileReader("client.properties", StandardCharsets.UTF_8)) { props.load(reader); } Verify that the Kafka client can access the Kafka brokers. 15.4.6.4. Configuring OAuth 2.0 for Kafka components This procedure describes how to configure Kafka components to use OAuth 2.0 authentication using an authorization server. You can configure authentication for: Kafka Connect Kafka MirrorMaker Kafka Bridge In this scenario, the Kafka component and the authorization server are running in the same cluster. Before you start For more information on the configuration of OAuth 2.0 authentication for Kafka components, see the KafkaClientAuthenticationOAuth schema reference . The schema reference includes examples of configuration options. Prerequisites Streams for Apache Kafka and Kafka are running An OAuth 2.0 authorization server is deployed and configured for OAuth access to Kafka brokers Kafka brokers are configured for OAuth 2.0 Procedure Create a client secret and mount it to the component as an environment variable. For example, here we are creating a client Secret for the Kafka Bridge: apiVersion: kafka.strimzi.io/v1beta2 kind: Secret metadata: name: my-bridge-oauth type: Opaque data: clientSecret: MGQ1OTRmMzYtZTllZS00MDY2LWI5OGEtMTM5MzM2NjdlZjQw 1 1 The clientSecret key must be in base64 format. Create or edit the resource for the Kafka component so that OAuth 2.0 authentication is configured for the authentication property. For OAuth 2.0 authentication, you can use the following options: Client ID and secret Client ID and refresh token Access token Username and password TLS For example, here OAuth 2.0 is assigned to the Kafka Bridge client using a client ID and secret, and TLS: apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaBridge metadata: name: my-bridge spec: # ... authentication: type: oauth 1 tokenEndpointUri: https://<auth-server-address>/auth/realms/master/protocol/openid-connect/token 2 clientId: kafka-bridge clientSecret: secretName: my-bridge-oauth key: clientSecret tlsTrustedCertificates: 3 - secretName: oauth-server-cert certificate: tls.crt 1 Authentication type set to oauth . 2 URI of the token endpoint for authentication. 3 Trusted certificates for TLS connection to the authorization server. Depending on how you apply OAuth 2.0 authentication, and the type of authorization server, there are additional configuration options you can use: # ... spec: # ... authentication: # ... disableTlsHostnameVerification: true 1 checkAccessTokenType: false 2 accessTokenIsJwt: false 3 scope: any 4 audience: kafka 5 connectTimeoutSeconds: 60 6 readTimeoutSeconds: 60 7 httpRetries: 2 8 httpRetryPauseMs: 300 9 includeAcceptHeader: false 10 1 (Optional) Disable TLS hostname verification. Default is false . 2 If the authorization server does not return a typ (type) claim inside the JWT token, you can apply checkAccessTokenType: false to skip the token type check. Default is true . 3 If you are using opaque tokens, you can apply accessTokenIsJwt: false so that access tokens are not treated as JWT tokens. 4 (Optional) The scope for requesting the token from the token endpoint. An authorization server may require a client to specify the scope. In this case it is any . 5 (Optional) The audience for requesting the token from the token endpoint. An authorization server may require a client to specify the audience. In this case it is kafka . 6 (Optional) The connect timeout in seconds when connecting to the authorization server. The default value is 60. 7 (Optional) The read timeout in seconds when connecting to the authorization server. The default value is 60. 8 (Optional) The maximum number of times to retry a failed HTTP request to the authorization server. The default value is 0 , meaning that no retries are performed. To use this option effectively, consider reducing the timeout times for the connectTimeoutSeconds and readTimeoutSeconds options. However, note that retries may prevent the current worker thread from being available to other requests, and if too many requests stall, it could make the Kafka broker unresponsive. 9 (Optional) The time to wait before attempting another retry of a failed HTTP request to the authorization server. By default, this time is set to zero, meaning that no pause is applied. This is because many issues that cause failed requests are per-request network glitches or proxy issues that can be resolved quickly. However, if your authorization server is under stress or experiencing high traffic, you may want to set this option to a value of 100 ms or more to reduce the load on the server and increase the likelihood of successful retries. 10 (Optional) Some authorization servers have issues with client sending Accept: application/json header. By setting includeAcceptHeader: false the header will not be sent. Default is true . Apply the changes to the deployment of your Kafka resource. oc apply -f your-file Check the update in the logs or by watching the pod state transitions: oc logs -f USD{POD_NAME} -c USD{CONTAINER_NAME} oc get pod -w The rolling updates configure the component for interaction with Kafka brokers using OAuth 2.0 authentication. 15.5. Using OAuth 2.0 token-based authorization If you are using OAuth 2.0 with Red Hat Single Sign-On for token-based authentication, you can also use Red Hat Single Sign-On to configure authorization rules to constrain client access to Kafka brokers. Authentication establishes the identity of a user. Authorization decides the level of access for that user. Streams for Apache Kafka supports the use of OAuth 2.0 token-based authorization through Red Hat Single Sign-On Authorization Services , which allows you to manage security policies and permissions centrally. Security policies and permissions defined in Red Hat Single Sign-On are used to grant access to resources on Kafka brokers. Users and clients are matched against policies that permit access to perform specific actions on Kafka brokers. Kafka allows all users full access to brokers by default, and also provides the AclAuthorizer and StandardAuthorizer plugins to configure authorization based on Access Control Lists (ACLs). The ACL rules managed by these plugins are used to grant or deny access to resources based on the username , and these rules are stored within the Kafka cluster itself. However, OAuth 2.0 token-based authorization with Red Hat Single Sign-On offers far greater flexibility on how you wish to implement access control to Kafka brokers. In addition, you can configure your Kafka brokers to use OAuth 2.0 authorization and ACLs. Additional resources Using OAuth 2.0 token-based authentication Kafka Authorization Red Hat Single Sign-On documentation 15.5.1. OAuth 2.0 authorization mechanism OAuth 2.0 authorization in Streams for Apache Kafka uses Red Hat Single Sign-On server Authorization Services REST endpoints to extend token-based authentication with Red Hat Single Sign-On by applying defined security policies on a particular user, and providing a list of permissions granted on different resources for that user. Policies use roles and groups to match permissions to users. OAuth 2.0 authorization enforces permissions locally based on the received list of grants for the user from Red Hat Single Sign-On Authorization Services. 15.5.1.1. Kafka broker custom authorizer A Red Hat Single Sign-On authorizer ( KeycloakAuthorizer ) is provided with Streams for Apache Kafka. To be able to use the Red Hat Single Sign-On REST endpoints for Authorization Services provided by Red Hat Single Sign-On, you configure a custom authorizer on the Kafka broker. The authorizer fetches a list of granted permissions from the authorization server as needed, and enforces authorization locally on the Kafka Broker, making rapid authorization decisions for each client request. 15.5.2. Configuring OAuth 2.0 authorization support This procedure describes how to configure Kafka brokers to use OAuth 2.0 authorization using Red Hat Single Sign-On Authorization Services. Before you begin Consider the access you require or want to limit for certain users. You can use a combination of Red Hat Single Sign-On groups , roles , clients , and users to configure access in Red Hat Single Sign-On. Typically, groups are used to match users based on organizational departments or geographical locations. And roles are used to match users based on their function. With Red Hat Single Sign-On, you can store users and groups in LDAP, whereas clients and roles cannot be stored this way. Storage and access to user data may be a factor in how you choose to configure authorization policies. Note Super users always have unconstrained access to a Kafka broker regardless of the authorization implemented on the Kafka broker. Prerequisites Streams for Apache Kafka must be configured to use OAuth 2.0 with Red Hat Single Sign-On for token-based authentication . You use the same Red Hat Single Sign-On server endpoint when you set up authorization. OAuth 2.0 authentication must be configured with the maxSecondsWithoutReauthentication option to enable re-authentication. Procedure Access the Red Hat Single Sign-On Admin Console or use the Red Hat Single Sign-On Admin CLI to enable Authorization Services for the Kafka broker client you created when setting up OAuth 2.0 authentication. Use Authorization Services to define resources, authorization scopes, policies, and permissions for the client. Bind the permissions to users and clients by assigning them roles and groups. Configure the Kafka brokers to use Red Hat Single Sign-On authorization by updating the Kafka broker configuration ( Kafka.spec.kafka ) of your Kafka resource in an editor. oc edit kafka my-cluster Configure the Kafka broker kafka configuration to use keycloak authorization, and to be able to access the authorization server and Authorization Services. For example: apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka metadata: name: my-cluster spec: kafka: # ... authorization: type: keycloak 1 tokenEndpointUri: < https://<auth-server-address>/auth/realms/external/protocol/openid-connect/token > 2 clientId: kafka 3 delegateToKafkaAcls: false 4 disableTlsHostnameVerification: false 5 superUsers: 6 - CN=fred - sam - CN=edward tlsTrustedCertificates: 7 - secretName: oauth-server-cert certificate: ca.crt grantsRefreshPeriodSeconds: 60 8 grantsRefreshPoolSize: 5 9 grantsMaxIdleSeconds: 300 10 grantsGcPeriodSeconds: 300 11 grantsAlwaysLatest: false 12 connectTimeoutSeconds: 60 13 readTimeoutSeconds: 60 14 httpRetries: 2 15 enableMetrics: false 16 includeAcceptHeader: false 17 #... 1 Type keycloak enables Red Hat Single Sign-On authorization. 2 URI of the Red Hat Single Sign-On token endpoint. For production, always use https:// urls. When you configure token-based oauth authentication, you specify a jwksEndpointUri as the URI for local JWT validation. The hostname for the tokenEndpointUri URI must be the same. 3 The client ID of the OAuth 2.0 client definition in Red Hat Single Sign-On that has Authorization Services enabled. Typically, kafka is used as the ID. 4 (Optional) Delegate authorization to Kafka AclAuthorizer and StandardAuthorizer if access is denied by Red Hat Single Sign-On Authorization Services policies. Default is false . 5 (Optional) Disable TLS hostname verification. Default is false . 6 (Optional) Designated super users. 7 (Optional) Trusted certificates for TLS connection to the authorization server. 8 (Optional) The time between two consecutive grants refresh runs. That is the maximum time for active sessions to detect any permissions changes for the user on Red Hat Single Sign-On. The default value is 60. 9 (Optional) The number of threads to use to refresh (in parallel) the grants for the active sessions. The default value is 5. 10 (Optional) The time, in seconds, after which an idle grant in the cache can be evicted. The default value is 300. 11 (Optional) The time, in seconds, between consecutive runs of a job that cleans stale grants from the cache. The default value is 300. 12 (Optional) Controls whether the latest grants are fetched for a new session. When enabled, grants are retrieved from Red Hat Single Sign-On and cached for the user. The default value is false . 13 (Optional) The connect timeout in seconds when connecting to the Red Hat Single Sign-On token endpoint. The default value is 60. 14 (Optional) The read timeout in seconds when connecting to the Red Hat Single Sign-On token endpoint. The default value is 60. 15 (Optional) The maximum number of times to retry (without pausing) a failed HTTP request to the authorization server. The default value is 0 , meaning that no retries are performed. To use this option effectively, consider reducing the timeout times for the connectTimeoutSeconds and readTimeoutSeconds options. However, note that retries may prevent the current worker thread from being available to other requests, and if too many requests stall, it could make the Kafka broker unresponsive. 16 (Optional) Enable or disable OAuth metrics. The default value is false . 17 (Optional) Some authorization servers have issues with client sending Accept: application/json header. By setting includeAcceptHeader: false the header will not be sent. Default is true . Save and exit the editor, then wait for rolling updates to complete. Check the update in the logs or by watching the pod state transitions: oc logs -f USD{POD_NAME} -c kafka oc get pod -w The rolling update configures the brokers to use OAuth 2.0 authorization. Verify the configured permissions by accessing Kafka brokers as clients or users with specific roles, making sure they have the necessary access, or do not have the access they are not supposed to have. 15.5.3. Managing policies and permissions in Red Hat Single Sign-On Authorization Services This section describes the authorization models used by Red Hat Single Sign-On Authorization Services and Kafka, and defines the important concepts in each model. To grant permissions to access Kafka, you can map Red Hat Single Sign-On Authorization Services objects to Kafka resources by creating an OAuth client specification in Red Hat Single Sign-On. Kafka permissions are granted to user accounts or service accounts using Red Hat Single Sign-On Authorization Services rules. Examples are shown of the different user permissions required for common Kafka operations, such as creating and listing topics. 15.5.3.1. Kafka and Red Hat Single Sign-On authorization models overview Kafka and Red Hat Single Sign-On Authorization Services use different authorization models. Kafka authorization model Kafka's authorization model uses resource types . When a Kafka client performs an action on a broker, the broker uses the configured KeycloakAuthorizer to check the client's permissions, based on the action and resource type. Kafka uses five resource types to control access: Topic , Group , Cluster , TransactionalId , and DelegationToken . Each resource type has a set of available permissions. Topic Create Write Read Delete Describe DescribeConfigs Alter AlterConfigs Group Read Describe Delete Cluster Create Describe Alter DescribeConfigs AlterConfigs IdempotentWrite ClusterAction TransactionalId Describe Write DelegationToken Describe Red Hat Single Sign-On Authorization Services model The Red Hat Single Sign-On Authorization Services model has four concepts for defining and granting permissions: resources , authorization scopes , policies , and permissions . Resources A resource is a set of resource definitions that are used to match resources with permitted actions. A resource might be an individual topic, for example, or all topics with names starting with the same prefix. A resource definition is associated with a set of available authorization scopes, which represent a set of all actions available on the resource. Often, only a subset of these actions is actually permitted. Authorization scopes An authorization scope is a set of all the available actions on a specific resource definition. When you define a new resource, you add scopes from the set of all scopes. Policies A policy is an authorization rule that uses criteria to match against a list of accounts. Policies can match: Service accounts based on client ID or roles User accounts based on username, groups, or roles. Permissions A permission grants a subset of authorization scopes on a specific resource definition to a set of users. Additional resources Kafka authorization model 15.5.3.2. Map Red Hat Single Sign-On Authorization Services to the Kafka authorization model The Kafka authorization model is used as a basis for defining the Red Hat Single Sign-On roles and resources that will control access to Kafka. To grant Kafka permissions to user accounts or service accounts, you first create an OAuth client specification in Red Hat Single Sign-On for the Kafka broker. You then specify Red Hat Single Sign-On Authorization Services rules on the client. Typically, the client id of the OAuth client that represents the broker is kafka . The example configuration files provided with Streams for Apache Kafka use kafka as the OAuth client id. Note If you have multiple Kafka clusters, you can use a single OAuth client ( kafka ) for all of them. This gives you a single, unified space in which to define and manage authorization rules. However, you can also use different OAuth client ids (for example, my-cluster-kafka or cluster-dev-kafka ) and define authorization rules for each cluster within each client configuration. The kafka client definition must have the Authorization Enabled option enabled in the Red Hat Single Sign-On Admin Console. All permissions exist within the scope of the kafka client. If you have different Kafka clusters configured with different OAuth client IDs, they each need a separate set of permissions even though they're part of the same Red Hat Single Sign-On realm. When the Kafka client uses OAUTHBEARER authentication, the Red Hat Single Sign-On authorizer ( KeycloakAuthorizer ) uses the access token of the current session to retrieve a list of grants from the Red Hat Single Sign-On server. To retrieve the grants, the authorizer evaluates the Red Hat Single Sign-On Authorization Services policies and permissions. Authorization scopes for Kafka permissions An initial Red Hat Single Sign-On configuration usually involves uploading authorization scopes to create a list of all possible actions that can be performed on each Kafka resource type. This step is performed once only, before defining any permissions. You can add authorization scopes manually instead of uploading them. Authorization scopes must contain all the possible Kafka permissions regardless of the resource type: Create Write Read Delete Describe Alter DescribeConfig AlterConfig ClusterAction IdempotentWrite Note If you're certain you won't need a permission (for example, IdempotentWrite ), you can omit it from the list of authorization scopes. However, that permission won't be available to target on Kafka resources. Resource patterns for permissions checks Resource patterns are used for pattern matching against the targeted resources when performing permission checks. The general pattern format is RESOURCE-TYPE:PATTERN-NAME . The resource types mirror the Kafka authorization model. The pattern allows for two matching options: Exact matching (when the pattern does not end with * ) Prefix matching (when the pattern ends with * ) Example patterns for resources Additionally, the general pattern format can be prefixed by kafka-cluster: CLUSTER-NAME followed by a comma, where CLUSTER-NAME refers to the metadata.name in the Kafka custom resource. Example patterns for resources with cluster prefix When the kafka-cluster prefix is missing, it is assumed to be kafka-cluster:* . When defining a resource, you can associate it with a list of possible authorization scopes which are relevant to the resource. Set whatever actions make sense for the targeted resource type. Though you may add any authorization scope to any resource, only the scopes supported by the resource type are considered for access control. Policies for applying access permission Policies are used to target permissions to one or more user accounts or service accounts. Targeting can refer to: Specific user or service accounts Realm roles or client roles User groups JavaScript rules to match a client IP address A policy is given a unique name and can be reused to target multiple permissions to multiple resources. Permissions to grant access Use fine-grained permissions to pull together the policies, resources, and authorization scopes that grant access to users. The name of each permission should clearly define which permissions it grants to which users. For example, Dev Team B can read from topics starting with x . Additional resources For more information about how to configure permissions through Red Hat Single Sign-On Authorization Services, see Section 15.5.4, "Trying Red Hat Single Sign-On Authorization Services" . 15.5.3.3. Example permissions required for Kafka operations The following examples demonstrate the user permissions required for performing common operations on Kafka. Create a topic To create a topic, the Create permission is required for the specific topic, or for Cluster:kafka-cluster . bin/kafka-topics.sh --create --topic my-topic \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties List topics If a user has the Describe permission on a specified topic, the topic is listed. bin/kafka-topics.sh --list \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties Display topic details To display a topic's details, Describe and DescribeConfigs permissions are required on the topic. bin/kafka-topics.sh --describe --topic my-topic \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties Produce messages to a topic To produce messages to a topic, Describe and Write permissions are required on the topic. If the topic hasn't been created yet, and topic auto-creation is enabled, the permissions to create a topic are required. bin/kafka-console-producer.sh --topic my-topic \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --producer.config=/tmp/config.properties Consume messages from a topic To consume messages from a topic, Describe and Read permissions are required on the topic. Consuming from the topic normally relies on storing the consumer offsets in a consumer group, which requires additional Describe and Read permissions on the consumer group. Two resources are needed for matching. For example: bin/kafka-console-consumer.sh --topic my-topic --group my-group-1 --from-beginning \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --consumer.config /tmp/config.properties Produce messages to a topic using an idempotent producer As well as the permissions for producing to a topic, an additional IdempotentWrite permission is required on the Cluster:kafka-cluster resource. Two resources are needed for matching. For example: bin/kafka-console-producer.sh --topic my-topic \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --producer.config=/tmp/config.properties --producer-property enable.idempotence=true --request-required-acks -1 List consumer groups When listing consumer groups, only the groups on which the user has the Describe permissions are returned. Alternatively, if the user has the Describe permission on the Cluster:kafka-cluster , all the consumer groups are returned. bin/kafka-consumer-groups.sh --list \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties Display consumer group details To display a consumer group's details, the Describe permission is required on the group and the topics associated with the group. bin/kafka-consumer-groups.sh --describe --group my-group-1 \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties Change topic configuration To change a topic's configuration, the Describe and Alter permissions are required on the topic. bin/kafka-topics.sh --alter --topic my-topic --partitions 2 \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties Display Kafka broker configuration In order to use kafka-configs.sh to get a broker's configuration, the DescribeConfigs permission is required on the Cluster:kafka-cluster . bin/kafka-configs.sh --entity-type brokers --entity-name 0 --describe --all \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties Change Kafka broker configuration To change a Kafka broker's configuration, DescribeConfigs and AlterConfigs permissions are required on Cluster:kafka-cluster . bin/kafka-configs --entity-type brokers --entity-name 0 --alter --add-config log.cleaner.threads=2 \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties Delete a topic To delete a topic, the Describe and Delete permissions are required on the topic. bin/kafka-topics.sh --delete --topic my-topic \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties Select a lead partition To run leader selection for topic partitions, the Alter permission is required on the Cluster:kafka-cluster . bin/kafka-leader-election.sh --topic my-topic --partition 0 --election-type PREFERRED / --bootstrap-server my-cluster-kafka-bootstrap:9092 --admin.config /tmp/config.properties Reassign partitions To generate a partition reassignment file, Describe permissions are required on the topics involved. bin/kafka-reassign-partitions.sh --topics-to-move-json-file /tmp/topics-to-move.json --broker-list "0,1" --generate \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config /tmp/config.properties > /tmp/partition-reassignment.json To execute the partition reassignment, Describe and Alter permissions are required on Cluster:kafka-cluster . Also, Describe permissions are required on the topics involved. bin/kafka-reassign-partitions.sh --reassignment-json-file /tmp/partition-reassignment.json --execute \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config /tmp/config.properties To verify partition reassignment, Describe , and AlterConfigs permissions are required on Cluster:kafka-cluster , and on each of the topics involved. bin/kafka-reassign-partitions.sh --reassignment-json-file /tmp/partition-reassignment.json --verify \ --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config /tmp/config.properties 15.5.4. Trying Red Hat Single Sign-On Authorization Services This example explains how to use Red Hat Single Sign-On Authorization Services with keycloak authorization. Use Red Hat Single Sign-On Authorization Services to enforce access restrictions on Kafka clients. Red Hat Single Sign-On Authorization Services use authorization scopes, policies and permissions to define and apply access control to resources. Red Hat Single Sign-On Authorization Services REST endpoints provide a list of granted permissions on resources for authenticated users. The list of grants (permissions) is fetched from the Red Hat Single Sign-On server as the first action after an authenticated session is established by the Kafka client. The list is refreshed in the background so that changes to the grants are detected. Grants are cached and enforced locally on the Kafka broker for each user session to provide fast authorization decisions. Streams for Apache Kafka provides example configuration files . These include the following example files for setting up Red Hat Single Sign-On: kafka-ephemeral-oauth-single-keycloak-authz.yaml An example Kafka custom resource configured for OAuth 2.0 token-based authorization using Red Hat Single Sign-On. You can use the custom resource to deploy a Kafka cluster that uses keycloak authorization and token-based oauth authentication. kafka-authz-realm.json An example Red Hat Single Sign-On realm configured with sample groups, users, roles and clients. You can import the realm into a Red Hat Single Sign-On instance to set up fine-grained permissions to access Kafka. If you want to try the example with Red Hat Single Sign-On, use these files to perform the tasks outlined in this section in the order shown. Accessing the Red Hat Single Sign-On Admin Console Deploying a Kafka cluster with Red Hat Single Sign-On authorization Preparing TLS connectivity for a CLI Kafka client session Checking authorized access to Kafka using a CLI Kafka client session Authentication When you configure token-based oauth authentication, you specify a jwksEndpointUri as the URI for local JWT validation. When you configure keycloak authorization, you specify a tokenEndpointUri as the URI of the Red Hat Single Sign-On token endpoint. The hostname for both URIs must be the same. Targeted permissions with group or role policies In Red Hat Single Sign-On, confidential clients with service accounts enabled can authenticate to the server in their own name using a client ID and a secret. This is convenient for microservices that typically act in their own name, and not as agents of a particular user (like a web site). Service accounts can have roles assigned like regular users. They cannot, however, have groups assigned. As a consequence, if you want to target permissions to microservices using service accounts, you cannot use group policies, and should instead use role policies. Conversely, if you want to limit certain permissions only to regular user accounts where authentication with a username and password is required, you can achieve that as a side effect of using the group policies rather than the role policies. This is what is used in this example for permissions that start with ClusterManager . Performing cluster management is usually done interactively using CLI tools. It makes sense to require the user to log in before using the resulting access token to authenticate to the Kafka broker. In this case, the access token represents the specific user, rather than the client application. 15.5.4.1. Accessing the Red Hat Single Sign-On Admin Console Set up Red Hat Single Sign-On, then connect to its Admin Console and add the preconfigured realm. Use the example kafka-authz-realm.json file to import the realm. You can check the authorization rules defined for the realm in the Admin Console. The rules grant access to the resources on the Kafka cluster configured to use the example Red Hat Single Sign-On realm. Prerequisites A running OpenShift cluster. The Streams for Apache Kafka examples/security/keycloak-authorization/kafka-authz-realm.json file that contains the preconfigured realm. Procedure Install the Red Hat Single Sign-On server using the Red Hat Single Sign-On Operator as described in Server Installation and Configuration in the Red Hat Single Sign-On documentation. Wait until the Red Hat Single Sign-On instance is running. Get the external hostname to be able to access the Admin Console. NS=sso oc get ingress keycloak -n USDNS In this example, we assume the Red Hat Single Sign-On server is running in the sso namespace. Get the password for the admin user. oc get -n USDNS pod keycloak-0 -o yaml | less The password is stored as a secret, so get the configuration YAML file for the Red Hat Single Sign-On instance to identify the name of the secret ( secretKeyRef.name ). Use the name of the secret to obtain the clear text password. SECRET_NAME=credential-keycloak oc get -n USDNS secret USDSECRET_NAME -o yaml | grep PASSWORD | awk '{print USD2}' | base64 -D In this example, we assume the name of the secret is credential-keycloak . Log in to the Admin Console with the username admin and the password you obtained. Use https:// HOSTNAME to access the Kubernetes Ingress . You can now upload the example realm to Red Hat Single Sign-On using the Admin Console. Click Add Realm to import the example realm. Add the examples/security/keycloak-authorization/kafka-authz-realm.json file, and then click Create . You now have kafka-authz as your current realm in the Admin Console. The default view displays the Master realm. In the Red Hat Single Sign-On Admin Console, go to Clients > kafka > Authorization > Settings and check that Decision Strategy is set to Affirmative . An affirmative policy means that at least one policy must be satisfied for a client to access the Kafka cluster. In the Red Hat Single Sign-On Admin Console, go to Groups , Users , Roles and Clients to view the realm configuration. Groups Groups are used to create user groups and set user permissions. Groups are sets of users with a name assigned. They are used to compartmentalize users into geographical, organizational or departmental units. Groups can be linked to an LDAP identity provider. You can make a user a member of a group through a custom LDAP server admin user interface, for example, to grant permissions on Kafka resources. Users Users are used to create users. For this example, alice and bob are defined. alice is a member of the ClusterManager group and bob is a member of ClusterManager-my-cluster group. Users can be stored in an LDAP identity provider. Roles Roles mark users or clients as having certain permissions. Roles are a concept analogous to groups. They are usually used to tag users with organizational roles and have the requisite permissions. Roles cannot be stored in an LDAP identity provider. If LDAP is a requirement, you can use groups instead, and add Red Hat Single Sign-On roles to the groups so that when users are assigned a group they also get a corresponding role. Clients Clients can have specific configurations. For this example, kafka , kafka-cli , team-a-client , and team-b-client clients are configured. The kafka client is used by Kafka brokers to perform the necessary OAuth 2.0 communication for access token validation. This client also contains the authorization services resource definitions, policies, and authorization scopes used to perform authorization on the Kafka brokers. The authorization configuration is defined in the kafka client from the Authorization tab, which becomes visible when Authorization Enabled is switched on from the Settings tab. The kafka-cli client is a public client that is used by the Kafka command line tools when authenticating with username and password to obtain an access token or a refresh token. The team-a-client and team-b-client clients are confidential clients representing services with partial access to certain Kafka topics. In the Red Hat Single Sign-On Admin Console, go to Authorization > Permissions to see the granted permissions that use the resources and policies defined for the realm. For example, the kafka client has the following permissions: Dev Team A The Dev Team A realm role can write to topics that start with x_ on any cluster. This combines a resource called Topic:x_* , Describe and Write scopes, and the Dev Team A policy. The Dev Team A policy matches all users that have a realm role called Dev Team A . Dev Team B The Dev Team B realm role can read from topics that start with x_ on any cluster. This combines Topic:x_* , Group:x_* resources, Describe and Read scopes, and the Dev Team B policy. The Dev Team B policy matches all users that have a realm role called Dev Team B . Matching users and clients have the ability to read from topics, and update the consumed offsets for topics and consumer groups that have names starting with x_ . 15.5.4.2. Deploying a Kafka cluster with Red Hat Single Sign-On authorization Deploy a Kafka cluster configured to connect to the Red Hat Single Sign-On server. Use the example kafka-ephemeral-oauth-single-keycloak-authz.yaml file to deploy the Kafka cluster as a Kafka custom resource. The example deploys a single-node Kafka cluster with keycloak authorization and oauth authentication. Prerequisites The Red Hat Single Sign-On authorization server is deployed to your OpenShift cluster and loaded with the example realm. The Cluster Operator is deployed to your OpenShift cluster. The Streams for Apache Kafka examples/security/keycloak-authorization/kafka-ephemeral-oauth-single-keycloak-authz.yaml custom resource. Procedure Use the hostname of the Red Hat Single Sign-On instance you deployed to prepare a truststore certificate for Kafka brokers to communicate with the Red Hat Single Sign-On server. SSO_HOST= SSO-HOSTNAME SSO_HOST_PORT=USDSSO_HOST:443 STOREPASS=storepass echo "Q" | openssl s_client -showcerts -connect USDSSO_HOST_PORT 2>/dev/null | awk ' /BEGIN CERTIFICATE/,/END CERTIFICATE/ { print USD0 } ' > /tmp/sso.pem The certificate is required as Kubernetes Ingress is used to make a secure (HTTPS) connection. Usually there is not one single certificate, but a certificate chain. You only have to provide the top-most issuer CA, which is listed last in the /tmp/sso.pem file. You can extract it manually or using the following commands: Example command to extract the top CA certificate in a certificate chain split -p "-----BEGIN CERTIFICATE-----" sso.pem sso- for f in USD(ls sso-*); do mv USDf USDf.pem; done cp USD(ls sso-* | sort -r | head -n 1) sso-ca.crt Note A trusted CA certificate is normally obtained from a trusted source, and not by using the openssl command. Deploy the certificate to OpenShift as a secret. oc create secret generic oauth-server-cert --from-file=/tmp/sso-ca.crt -n USDNS Set the hostname as an environment variable SSO_HOST= SSO-HOSTNAME Create and deploy the example Kafka cluster. cat examples/security/keycloak-authorization/kafka-ephemeral-oauth-single-keycloak-authz.yaml | sed -E 's#\USD{SSO_HOST}'"#USDSSO_HOST#" | oc create -n USDNS -f - 15.5.4.3. Preparing TLS connectivity for a CLI Kafka client session Create a new pod for an interactive CLI session. Set up a truststore with a Red Hat Single Sign-On certificate for TLS connectivity. The truststore is to connect to Red Hat Single Sign-On and the Kafka broker. Prerequisites The Red Hat Single Sign-On authorization server is deployed to your OpenShift cluster and loaded with the example realm. In the Red Hat Single Sign-On Admin Console, check the roles assigned to the clients are displayed in Clients > Service Account Roles . The Kafka cluster configured to connect with Red Hat Single Sign-On is deployed to your OpenShift cluster. Procedure Run a new interactive pod container using the Streams for Apache Kafka image to connect to a running Kafka broker. NS=sso oc run -ti --restart=Never --image=registry.redhat.io/amq-streams/kafka-37-rhel9:2.7.0 kafka-cli -n USDNS -- /bin/sh Note If oc times out waiting on the image download, subsequent attempts may result in an AlreadyExists error. Attach to the pod container. oc attach -ti kafka-cli -n USDNS Use the hostname of the Red Hat Single Sign-On instance to prepare a certificate for client connection using TLS. SSO_HOST= SSO-HOSTNAME SSO_HOST_PORT=USDSSO_HOST:443 STOREPASS=storepass echo "Q" | openssl s_client -showcerts -connect USDSSO_HOST_PORT 2>/dev/null | awk ' /BEGIN CERTIFICATE/,/END CERTIFICATE/ { print USD0 } ' > /tmp/sso.pem Usually there is not one single certificate, but a certificate chain. You only have to provide the top-most issuer CA, which is listed last in the /tmp/sso.pem file. You can extract it manually or using the following command: Example command to extract the top CA certificate in a certificate chain split -p "-----BEGIN CERTIFICATE-----" sso.pem sso- for f in USD(ls sso-*); do mv USDf USDf.pem; done cp USD(ls sso-* | sort -r | head -n 1) sso-ca.crt Note A trusted CA certificate is normally obtained from a trusted source, and not by using the openssl command. Create a truststore for TLS connection to the Kafka brokers. keytool -keystore /tmp/truststore.p12 -storetype pkcs12 -alias sso -storepass USDSTOREPASS -import -file /tmp/sso-ca.crt -noprompt Use the Kafka bootstrap address as the hostname of the Kafka broker and the tls listener port (9093) to prepare a certificate for the Kafka broker. KAFKA_HOST_PORT=my-cluster-kafka-bootstrap:9093 STOREPASS=storepass echo "Q" | openssl s_client -showcerts -connect USDKAFKA_HOST_PORT 2>/dev/null | awk ' /BEGIN CERTIFICATE/,/END CERTIFICATE/ { print USD0 } ' > /tmp/my-cluster-kafka.pem The obtained .pem file is usually not one single certificate, but a certificate chain. You only have to provide the top-most issuer CA, which is listed last in the /tmp/my-cluster-kafka.pem file. You can extract it manually or using the following command: Example command to extract the top CA certificate in a certificate chain split -p "-----BEGIN CERTIFICATE-----" /tmp/my-cluster-kafka.pem kafka- for f in USD(ls kafka-*); do mv USDf USDf.pem; done cp USD(ls kafka-* | sort -r | head -n 1) my-cluster-kafka-ca.crt Note A trusted CA certificate is normally obtained from a trusted source, and not by using the openssl command. For this example we assume the client is running in a pod in the same namespace where the Kafka cluster was deployed. If the client is accessing the Kafka cluster from outside the OpenShift cluster, you would have to first determine the bootstrap address. In that case you can also get the cluster certificate directly from the OpenShift secret, and there is no need for openssl . For more information, see Chapter 14, Setting up client access to a Kafka cluster . Add the certificate for the Kafka broker to the truststore. keytool -keystore /tmp/truststore.p12 -storetype pkcs12 -alias my-cluster-kafka -storepass USDSTOREPASS -import -file /tmp/my-cluster-kafka-ca.crt -noprompt Keep the session open to check authorized access. 15.5.4.4. Checking authorized access to Kafka using a CLI Kafka client session Check the authorization rules applied through the Red Hat Single Sign-On realm using an interactive CLI session. Apply the checks using Kafka's example producer and consumer clients to create topics with user and service accounts that have different levels of access. Use the team-a-client and team-b-client clients to check the authorization rules. Use the alice admin user to perform additional administrative tasks on Kafka. The Streams for Apache Kafka image used in this example contains Kafka producer and consumer binaries. Prerequisites ZooKeeper and Kafka are running in the OpenShift cluster to be able to send and receive messages. The interactive CLI Kafka client session is started. Apache Kafka download . Setting up client and admin user configuration Prepare a Kafka configuration file with authentication properties for the team-a-client client. SSO_HOST= SSO-HOSTNAME cat > /tmp/team-a-client.properties << EOF security.protocol=SASL_SSL ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.mechanism=OAUTHBEARER sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required \ oauth.client.id="team-a-client" \ oauth.client.secret="team-a-client-secret" \ oauth.ssl.truststore.location="/tmp/truststore.p12" \ oauth.ssl.truststore.password="USDSTOREPASS" \ oauth.ssl.truststore.type="PKCS12" \ oauth.token.endpoint.uri="https://USDSSO_HOST/auth/realms/kafka-authz/protocol/openid-connect/token" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler EOF The SASL OAUTHBEARER mechanism is used. This mechanism requires a client ID and client secret, which means the client first connects to the Red Hat Single Sign-On server to obtain an access token. The client then connects to the Kafka broker and uses the access token to authenticate. Prepare a Kafka configuration file with authentication properties for the team-b-client client. cat > /tmp/team-b-client.properties << EOF security.protocol=SASL_SSL ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.mechanism=OAUTHBEARER sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required \ oauth.client.id="team-b-client" \ oauth.client.secret="team-b-client-secret" \ oauth.ssl.truststore.location="/tmp/truststore.p12" \ oauth.ssl.truststore.password="USDSTOREPASS" \ oauth.ssl.truststore.type="PKCS12" \ oauth.token.endpoint.uri="https://USDSSO_HOST/auth/realms/kafka-authz/protocol/openid-connect/token" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler EOF Authenticate admin user alice by using curl and performing a password grant authentication to obtain a refresh token. USERNAME=alice PASSWORD=alice-password GRANT_RESPONSE=USD(curl -X POST "https://USDSSO_HOST/auth/realms/kafka-authz/protocol/openid-connect/token" -H 'Content-Type: application/x-www-form-urlencoded' -d "grant_type=password&username=USDUSERNAME&password=USDPASSWORD&client_id=kafka-cli&scope=offline_access" -s -k) REFRESH_TOKEN=USD(echo USDGRANT_RESPONSE | awk -F "refresh_token\":\"" '{printf USD2}' | awk -F "\"" '{printf USD1}') The refresh token is an offline token that is long-lived and does not expire. Prepare a Kafka configuration file with authentication properties for the admin user alice . cat > /tmp/alice.properties << EOF security.protocol=SASL_SSL ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.mechanism=OAUTHBEARER sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required \ oauth.refresh.token="USDREFRESH_TOKEN" \ oauth.client.id="kafka-cli" \ oauth.ssl.truststore.location="/tmp/truststore.p12" \ oauth.ssl.truststore.password="USDSTOREPASS" \ oauth.ssl.truststore.type="PKCS12" \ oauth.token.endpoint.uri="https://USDSSO_HOST/auth/realms/kafka-authz/protocol/openid-connect/token" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler EOF The kafka-cli public client is used for the oauth.client.id in the sasl.jaas.config . Since it's a public client it does not require a secret. The client authenticates with the refresh token that was authenticated in the step. The refresh token requests an access token behind the scenes, which is then sent to the Kafka broker for authentication. Producing messages with authorized access Use the team-a-client configuration to check that you can produce messages to topics that start with a_ or x_ . Write to topic my-topic . bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic my-topic \ --producer.config=/tmp/team-a-client.properties First message This request returns a Not authorized to access topics: [my-topic] error. team-a-client has a Dev Team A role that gives it permission to perform any supported actions on topics that start with a_ , but can only write to topics that start with x_ . The topic named my-topic matches neither of those rules. Write to topic a_messages . bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic a_messages \ --producer.config /tmp/team-a-client.properties First message Second message Messages are produced to Kafka successfully. Press CTRL+C to exit the CLI application. Check the Kafka container log for a debug log of Authorization GRANTED for the request. oc logs my-cluster-kafka-0 -f -n USDNS Consuming messages with authorized access Use the team-a-client configuration to consume messages from topic a_messages . Fetch messages from topic a_messages . bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic a_messages \ --from-beginning --consumer.config /tmp/team-a-client.properties The request returns an error because the Dev Team A role for team-a-client only has access to consumer groups that have names starting with a_ . Update the team-a-client properties to specify the custom consumer group it is permitted to use. bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic a_messages \ --from-beginning --consumer.config /tmp/team-a-client.properties --group a_consumer_group_1 The consumer receives all the messages from the a_messages topic. Administering Kafka with authorized access The team-a-client is an account without any cluster-level access, but it can be used with some administrative operations. List topics. bin/kafka-topics.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/team-a-client.properties --list The a_messages topic is returned. List consumer groups. bin/kafka-consumer-groups.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/team-a-client.properties --list The a_consumer_group_1 consumer group is returned. Fetch details on the cluster configuration. bin/kafka-configs.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/team-a-client.properties \ --entity-type brokers --describe --entity-default The request returns an error because the operation requires cluster level permissions that team-a-client does not have. Using clients with different permissions Use the team-b-client configuration to produce messages to topics that start with b_ . Write to topic a_messages . bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic a_messages \ --producer.config /tmp/team-b-client.properties Message 1 This request returns a Not authorized to access topics: [a_messages] error. Write to topic b_messages . bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic b_messages \ --producer.config /tmp/team-b-client.properties Message 1 Message 2 Message 3 Messages are produced to Kafka successfully. Write to topic x_messages . bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages \ --producer.config /tmp/team-b-client.properties Message 1 A Not authorized to access topics: [x_messages] error is returned, The team-b-client can only read from topic x_messages . Write to topic x_messages using team-a-client . bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages \ --producer.config /tmp/team-a-client.properties Message 1 This request returns a Not authorized to access topics: [x_messages] error. The team-a-client can write to the x_messages topic, but it does not have a permission to create a topic if it does not yet exist. Before team-a-client can write to the x_messages topic, an admin power user must create it with the correct configuration, such as the number of partitions and replicas. Managing Kafka with an authorized admin user Use admin user alice to manage Kafka. alice has full access to manage everything on any Kafka cluster. Create the x_messages topic as alice . bin/kafka-topics.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/alice.properties \ --topic x_messages --create --replication-factor 1 --partitions 1 The topic is created successfully. List all topics as alice . bin/kafka-topics.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/alice.properties --list bin/kafka-topics.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/team-a-client.properties --list bin/kafka-topics.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/team-b-client.properties --list Admin user alice can list all the topics, whereas team-a-client and team-b-client can only list the topics they have access to. The Dev Team A and Dev Team B roles both have Describe permission on topics that start with x_ , but they cannot see the other team's topics because they do not have Describe permissions on them. Use the team-a-client to produce messages to the x_messages topic: bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages \ --producer.config /tmp/team-a-client.properties Message 1 Message 2 Message 3 As alice created the x_messages topic, messages are produced to Kafka successfully. Use the team-b-client to produce messages to the x_messages topic. bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages \ --producer.config /tmp/team-b-client.properties Message 4 Message 5 This request returns a Not authorized to access topics: [x_messages] error. Use the team-b-client to consume messages from the x_messages topic: bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages \ --from-beginning --consumer.config /tmp/team-b-client.properties --group x_consumer_group_b The consumer receives all the messages from the x_messages topic. Use the team-a-client to consume messages from the x_messages topic. bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages \ --from-beginning --consumer.config /tmp/team-a-client.properties --group x_consumer_group_a This request returns a Not authorized to access topics: [x_messages] error. Use the team-a-client to consume messages from a consumer group that begins with a_ . bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages \ --from-beginning --consumer.config /tmp/team-a-client.properties --group a_consumer_group_a This request returns a Not authorized to access topics: [x_messages] error. Dev Team A has no Read access on topics that start with a x_ . Use alice to produce messages to the x_messages topic. bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages \ --from-beginning --consumer.config /tmp/alice.properties Messages are produced to Kafka successfully. alice can read from or write to any topic. Use alice to read the cluster configuration. bin/kafka-configs.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/alice.properties \ --entity-type brokers --describe --entity-default The cluster configuration for this example is empty. Additional resources Server Installation and Configuration Map Red Hat Single Sign-On Authorization Services to the Kafka authorization model

Commands:
apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka metadata: name: my-cluster namespace: myproject spec: kafka: # listeners: - name: plain port: 9092 type: internal tls: true authentication: type: scram-sha-512 - name: tls port: 9093 type: internal tls: true authentication: type: tls - name: external3 port: 9094 type: loadbalancer tls: true authentication: type: tls
apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka metadata: name: my-cluster namespace: myproject spec: kafka: # authorization: type: simple superUsers: - CN=client_1 - user_2 - CN=client_3 - CN=client_4,OU=my_ou,O=my_org,L=my_location,ST=my_state,C=US - CN=client_5,OU=my_ou,O=my_org,C=GB - CN=client_6,O=my_org #
apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster
apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: authentication: type: tls #
apiVersion: v1 kind: Secret metadata: name: my-user labels: strimzi.io/kind: KafkaUser strimzi.io/cluster: my-cluster type: Opaque data: ca.crt: <public_key> # Public key of the clients CA user.crt: <user_certificate> # Public key of the user user.key: <user_private_key> # Private key of the user user.p12: <store> # PKCS #12 store for user certificates and keys user.password: <password_for_store> # Protects the PKCS #12 store
bootstrap.servers= <kafka_cluster_name> -kafka-bootstrap:9093 1 security.protocol=SSL 2 ssl.truststore.location=/tmp/ca.p12 3 ssl.truststore.password= <truststore_password> 4 ssl.keystore.location=/tmp/user.p12 5 ssl.keystore.password= <keystore_password> 6
apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: authentication: type: tls-external #
apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: authentication: type: scram-sha-512 #
apiVersion: v1 kind: Secret metadata: name: my-user labels: strimzi.io/kind: KafkaUser strimzi.io/cluster: my-cluster type: Opaque data: password: Z2VuZXJhdGVkcGFzc3dvcmQ= 1 sasl.jaas.config: b3JnLmFwYWNoZS5rYWZrYS5jb21tb24uc2VjdXJpdHkuc2NyYW0uU2NyYW1Mb2dpbk1vZHVsZSByZXF1aXJlZCB1c2VybmFtZT0ibXktdXNlciIgcGFzc3dvcmQ9ImdlbmVyYXRlZHBhc3N3b3JkIjsK 2
echo "Z2VuZXJhdGVkcGFzc3dvcmQ=" | base64 --decode
apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: authentication: type: scram-sha-512 password: valueFrom: secretKeyRef: name: my-secret 1 key: my-password 2 #
apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: # quotas: producerByteRate: 1048576 1 consumerByteRate: 2097152 2 requestPercentage: 55 3 controllerMutationRate: 10 4
apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka spec: kafka: # authorization: 1 type: simple superUsers: 2 - CN=client_1 - user_2 - CN=client_3 listeners: - name: tls port: 9093 type: internal tls: true authentication: type: tls 3 # zookeeper: #
apply -f <kafka_configuration_file>
apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaUser metadata: name: my-user labels: strimzi.io/cluster: my-cluster spec: authentication: 1 type: tls authorization: type: simple 2 acls: - resource: type: topic name: my-topic patternType: literal operations: - Describe - Read - resource: type: group name: my-group patternType: literal operations: - Read
apply -f <user_config_file>
apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka spec: kafka: # listeners: - name: tls port: 9093 type: internal tls: true authentication: type: tls networkPolicyPeers: - podSelector: matchLabels: app: kafka-client # zookeeper: #
apply -f your-file
create secret generic my-secret --from-file= my-listener-key.key --from-file= my-listener-certificate.crt
listeners: - name: plain port: 9092 type: internal tls: false - name: external3 port: 9094 type: loadbalancer tls: true configuration: brokerCertChainAndKey: secretName: my-secret certificate: my-listener-certificate.crt key: my-listener-key.key
listeners: - name: plain port: 9092 type: internal tls: false - name: tls port: 9093 type: internal tls: true configuration: brokerCertChainAndKey: secretName: my-secret certificate: my-listener-certificate.crt key: my-listener-key.key
apply -f kafka.yaml
//Kafka brokers *. <cluster-name> -kafka-brokers *. <cluster-name> -kafka-brokers. <namespace> .svc // Bootstrap service <cluster-name> -kafka-bootstrap <cluster-name> -kafka-bootstrap. <namespace> .svc
// Kafka brokers <cluster-name> -kafka-0. <cluster-name> -kafka-brokers <cluster-name> -kafka-0. <cluster-name> -kafka-brokers. <namespace> .svc <cluster-name> -kafka-1. <cluster-name> -kafka-brokers <cluster-name> -kafka-1. <cluster-name> -kafka-brokers. <namespace> .svc // Bootstrap service <cluster-name> -kafka-bootstrap <cluster-name> -kafka-bootstrap. <namespace> .svc
// Kafka brokers <cluster-name> -kafka- <listener-name> -0 <cluster-name> -kafka- <listener-name> -0. <namespace> .svc <cluster-name> -kafka- <listener-name> -1 <cluster-name> -kafka- <listener-name> -1. <namespace> .svc // Bootstrap service <cluster-name> -kafka- <listener-name> -bootstrap <cluster-name> -kafka- <listener-name> -bootstrap. <namespace> .svc
authentication: type: oauth # enableOauthBearer: true
authentication: type: oauth # enablePlain: true tokenEndpointUri: https:// OAUTH-SERVER-ADDRESS /auth/realms/external/protocol/openid-connect/token
apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka spec: kafka: # listeners: - name: tls port: 9093 type: internal tls: true authentication: type: oauth #
listeners: - name: external3 port: 9094 type: loadbalancer tls: true authentication: type: oauth #
apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka spec: kafka: # listeners: - name: tls port: 9093 type: internal tls: true authentication: type: oauth validIssuerUri: <https://<auth_server_address>/auth/realms/tls> jwksEndpointUri: <https://<auth_server_address>/auth/realms/tls/protocol/openid-connect/certs> userNameClaim: preferred_username maxSecondsWithoutReauthentication: 3600 tlsTrustedCertificates: - secretName: oauth-server-cert certificate: ca.crt #
apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka spec: kafka: listeners: - name: tls port: 9093 type: internal tls: true authentication: type: oauth clientId: kafka-broker clientSecret: secretName: my-cluster-oauth key: clientSecret validIssuerUri: <https://<auth_server_-_address>/auth/realms/tls> introspectionEndpointUri: <https://<auth_server_address>/auth/realms/tls/protocol/openid-connect/token/introspect> userNameClaim: preferred_username maxSecondsWithoutReauthentication: 3600 tlsTrustedCertificates: - secretName: oauth-server-cert certificate: ca.crt
edit kafka my-cluster
# - name: external3 port: 9094 type: loadbalancer tls: true authentication: type: oauth 1 validIssuerUri: https://<auth_server_address>/auth/realms/external 2 jwksEndpointUri: https://<auth_server_address>/auth/realms/external/protocol/openid-connect/certs 3 userNameClaim: preferred_username 4 maxSecondsWithoutReauthentication: 3600 5 tlsTrustedCertificates: 6 - secretName: oauth-server-cert certificate: ca.crt disableTlsHostnameVerification: true 7 jwksExpirySeconds: 360 8 jwksRefreshSeconds: 300 9 jwksMinRefreshPauseSeconds: 1 10
- name: external3 port: 9094 type: loadbalancer tls: true authentication: type: oauth validIssuerUri: https://<auth_server_address>/auth/realms/external introspectionEndpointUri: https://<auth_server_address>/auth/realms/external/protocol/openid-connect/token/introspect 1 clientId: kafka-broker 2 clientSecret: 3 secretName: my-cluster-oauth key: clientSecret userNameClaim: preferred_username 4 maxSecondsWithoutReauthentication: 3600 5
authentication: type: oauth # checkIssuer: false 1 checkAudience: true 2 fallbackUserNameClaim: client_id 3 fallbackUserNamePrefix: client-account- 4 validTokenType: bearer 5 userInfoEndpointUri: https://<auth_server_address>/auth/realms/external/protocol/openid-connect/userinfo 6 enableOauthBearer: false 7 enablePlain: true 8 tokenEndpointUri: https://<auth_server_address>/auth/realms/external/protocol/openid-connect/token 9 customClaimCheck: "@.custom == 'custom-value'" 10 clientAudience: audience 11 clientScope: scope 12 connectTimeoutSeconds: 60 13 readTimeoutSeconds: 60 14 httpRetries: 2 15 httpRetryPauseMs: 300 16 groupsClaim: "USD.groups" 17 groupsClaimDelimiter: "," 18 includeAcceptHeader: false 19
logs -f USD{POD_NAME} -c USD{CONTAINER_NAME} get pod -w
<dependency> <groupId>io.strimzi</groupId> <artifactId>kafka-oauth-client</artifactId> <version>0.15.0.redhat-00007</version> </dependency>
security.protocol=SASL_SSL 1 sasl.mechanism=OAUTHBEARER 2 ssl.truststore.location=/tmp/truststore.p12 3 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required oauth.token.endpoint.uri="<token_endpoint_url>" \ 4 oauth.client.id="<client_id>" \ 5 oauth.client.secret="<client_secret>" \ 6 oauth.ssl.truststore.location="/tmp/oauth-truststore.p12" \ 7 oauth.ssl.truststore.password="USDSTOREPASS" \ 8 oauth.ssl.truststore.type="PKCS12" \ 9 oauth.scope="<scope>" \ 10 oauth.audience="<audience>" ; 11 sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler
security.protocol=SASL_SSL sasl.mechanism=OAUTHBEARER ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required oauth.token.endpoint.uri="<token_endpoint_url>" oauth.client.id="<client_id>" \ 1 oauth.client.secret="<client_secret>" \ 2 oauth.password.grant.username="<username>" \ 3 oauth.password.grant.password="<password>" \ 4 oauth.ssl.truststore.location="/tmp/oauth-truststore.p12" oauth.ssl.truststore.password="USDSTOREPASS" oauth.ssl.truststore.type="PKCS12" oauth.scope="<scope>" oauth.audience="<audience>" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler
security.protocol=SASL_SSL sasl.mechanism=OAUTHBEARER ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required oauth.token.endpoint.uri="<token_endpoint_url>" oauth.access.token="<access_token>" \ 1 oauth.ssl.truststore.location="/tmp/oauth-truststore.p12" oauth.ssl.truststore.password="USDSTOREPASS" oauth.ssl.truststore.type="PKCS12" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler
security.protocol=SASL_SSL sasl.mechanism=OAUTHBEARER ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required oauth.token.endpoint.uri="<token_endpoint_url>" oauth.client.id="<client_id>" \ 1 oauth.client.secret="<client_secret>" \ 2 oauth.refresh.token="<refresh_token>" \ 3 oauth.ssl.truststore.location="/tmp/oauth-truststore.p12" oauth.ssl.truststore.password="USDSTOREPASS" oauth.ssl.truststore.type="PKCS12" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler
Properties props = new Properties(); try (FileReader reader = new FileReader("client.properties", StandardCharsets.UTF_8)) { props.load(reader); }
apiVersion: kafka.strimzi.io/v1beta2 kind: Secret metadata: name: my-bridge-oauth type: Opaque data: clientSecret: MGQ1OTRmMzYtZTllZS00MDY2LWI5OGEtMTM5MzM2NjdlZjQw 1
apiVersion: kafka.strimzi.io/v1beta2 kind: KafkaBridge metadata: name: my-bridge spec: # authentication: type: oauth 1 tokenEndpointUri: https://<auth-server-address>/auth/realms/master/protocol/openid-connect/token 2 clientId: kafka-bridge clientSecret: secretName: my-bridge-oauth key: clientSecret tlsTrustedCertificates: 3 - secretName: oauth-server-cert certificate: tls.crt
spec: # authentication: # disableTlsHostnameVerification: true 1 checkAccessTokenType: false 2 accessTokenIsJwt: false 3 scope: any 4 audience: kafka 5 connectTimeoutSeconds: 60 6 readTimeoutSeconds: 60 7 httpRetries: 2 8 httpRetryPauseMs: 300 9 includeAcceptHeader: false 10
apply -f your-file
logs -f USD{POD_NAME} -c USD{CONTAINER_NAME} get pod -w
edit kafka my-cluster
apiVersion: kafka.strimzi.io/v1beta2 kind: Kafka metadata: name: my-cluster spec: kafka: # authorization: type: keycloak 1 tokenEndpointUri: < https://<auth-server-address>/auth/realms/external/protocol/openid-connect/token > 2 clientId: kafka 3 delegateToKafkaAcls: false 4 disableTlsHostnameVerification: false 5 superUsers: 6 - CN=fred - sam - CN=edward tlsTrustedCertificates: 7 - secretName: oauth-server-cert certificate: ca.crt grantsRefreshPeriodSeconds: 60 8 grantsRefreshPoolSize: 5 9 grantsMaxIdleSeconds: 300 10 grantsGcPeriodSeconds: 300 11 grantsAlwaysLatest: false 12 connectTimeoutSeconds: 60 13 readTimeoutSeconds: 60 14 httpRetries: 2 15 enableMetrics: false 16 includeAcceptHeader: false 17 #
logs -f USD{POD_NAME} -c kafka get pod -w
Topic:my-topic Topic:orders-* Group:orders-* Cluster:*
kafka-cluster:my-cluster,Topic:* kafka-cluster:*,Group:b_*
bin/kafka-topics.sh --create --topic my-topic --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties
bin/kafka-topics.sh --list --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties
bin/kafka-topics.sh --describe --topic my-topic --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties
bin/kafka-console-producer.sh --topic my-topic --bootstrap-server my-cluster-kafka-bootstrap:9092 --producer.config=/tmp/config.properties
Topic:my-topic Group:my-group-*
bin/kafka-console-consumer.sh --topic my-topic --group my-group-1 --from-beginning --bootstrap-server my-cluster-kafka-bootstrap:9092 --consumer.config /tmp/config.properties
Topic:my-topic Cluster:kafka-cluster
bin/kafka-console-producer.sh --topic my-topic --bootstrap-server my-cluster-kafka-bootstrap:9092 --producer.config=/tmp/config.properties --producer-property enable.idempotence=true --request-required-acks -1
bin/kafka-consumer-groups.sh --list --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties
bin/kafka-consumer-groups.sh --describe --group my-group-1 --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties
bin/kafka-topics.sh --alter --topic my-topic --partitions 2 --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties
bin/kafka-configs.sh --entity-type brokers --entity-name 0 --describe --all --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties
bin/kafka-configs --entity-type brokers --entity-name 0 --alter --add-config log.cleaner.threads=2 --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties
bin/kafka-topics.sh --delete --topic my-topic --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config=/tmp/config.properties
bin/kafka-leader-election.sh --topic my-topic --partition 0 --election-type PREFERRED / --bootstrap-server my-cluster-kafka-bootstrap:9092 --admin.config /tmp/config.properties
bin/kafka-reassign-partitions.sh --topics-to-move-json-file /tmp/topics-to-move.json --broker-list "0,1" --generate --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config /tmp/config.properties > /tmp/partition-reassignment.json
bin/kafka-reassign-partitions.sh --reassignment-json-file /tmp/partition-reassignment.json --execute --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config /tmp/config.properties
bin/kafka-reassign-partitions.sh --reassignment-json-file /tmp/partition-reassignment.json --verify --bootstrap-server my-cluster-kafka-bootstrap:9092 --command-config /tmp/config.properties
NS=sso get ingress keycloak -n USDNS
get -n USDNS pod keycloak-0 -o yaml | less
SECRET_NAME=credential-keycloak get -n USDNS secret USDSECRET_NAME -o yaml | grep PASSWORD | awk '{print USD2}' | base64 -D
Dev Team A can write to topics that start with x_ on any cluster Dev Team B can read from topics that start with x_ on any cluster Dev Team B can update consumer group offsets that start with x_ on any cluster ClusterManager of my-cluster Group has full access to cluster config on my-cluster ClusterManager of my-cluster Group has full access to consumer groups on my-cluster ClusterManager of my-cluster Group has full access to topics on my-cluster
SSO_HOST= SSO-HOSTNAME SSO_HOST_PORT=USDSSO_HOST:443 STOREPASS=storepass echo "Q" | openssl s_client -showcerts -connect USDSSO_HOST_PORT 2>/dev/null | awk ' /BEGIN CERTIFICATE/,/END CERTIFICATE/ { print USD0 } ' > /tmp/sso.pem
split -p "-----BEGIN CERTIFICATE-----" sso.pem sso- for f in USD(ls sso-*); do mv USDf USDf.pem; done cp USD(ls sso-* | sort -r | head -n 1) sso-ca.crt
create secret generic oauth-server-cert --from-file=/tmp/sso-ca.crt -n USDNS
SSO_HOST= SSO-HOSTNAME
cat examples/security/keycloak-authorization/kafka-ephemeral-oauth-single-keycloak-authz.yaml | sed -E 's#\USD{SSO_HOST}'"#USDSSO_HOST#" | oc create -n USDNS -f -
NS=sso run -ti --restart=Never --image=registry.redhat.io/amq-streams/kafka-37-rhel9:2.7.0 kafka-cli -n USDNS -- /bin/sh
attach -ti kafka-cli -n USDNS
SSO_HOST= SSO-HOSTNAME SSO_HOST_PORT=USDSSO_HOST:443 STOREPASS=storepass echo "Q" | openssl s_client -showcerts -connect USDSSO_HOST_PORT 2>/dev/null | awk ' /BEGIN CERTIFICATE/,/END CERTIFICATE/ { print USD0 } ' > /tmp/sso.pem
split -p "-----BEGIN CERTIFICATE-----" sso.pem sso- for f in USD(ls sso-*); do mv USDf USDf.pem; done cp USD(ls sso-* | sort -r | head -n 1) sso-ca.crt
keytool -keystore /tmp/truststore.p12 -storetype pkcs12 -alias sso -storepass USDSTOREPASS -import -file /tmp/sso-ca.crt -noprompt
KAFKA_HOST_PORT=my-cluster-kafka-bootstrap:9093 STOREPASS=storepass echo "Q" | openssl s_client -showcerts -connect USDKAFKA_HOST_PORT 2>/dev/null | awk ' /BEGIN CERTIFICATE/,/END CERTIFICATE/ { print USD0 } ' > /tmp/my-cluster-kafka.pem
split -p "-----BEGIN CERTIFICATE-----" /tmp/my-cluster-kafka.pem kafka- for f in USD(ls kafka-*); do mv USDf USDf.pem; done cp USD(ls kafka-* | sort -r | head -n 1) my-cluster-kafka-ca.crt
keytool -keystore /tmp/truststore.p12 -storetype pkcs12 -alias my-cluster-kafka -storepass USDSTOREPASS -import -file /tmp/my-cluster-kafka-ca.crt -noprompt
SSO_HOST= SSO-HOSTNAME cat > /tmp/team-a-client.properties << EOF security.protocol=SASL_SSL ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.mechanism=OAUTHBEARER sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required oauth.client.id="team-a-client" oauth.client.secret="team-a-client-secret" oauth.ssl.truststore.location="/tmp/truststore.p12" oauth.ssl.truststore.password="USDSTOREPASS" oauth.ssl.truststore.type="PKCS12" oauth.token.endpoint.uri="https://USDSSO_HOST/auth/realms/kafka-authz/protocol/openid-connect/token" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler EOF
cat > /tmp/team-b-client.properties << EOF security.protocol=SASL_SSL ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.mechanism=OAUTHBEARER sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required oauth.client.id="team-b-client" oauth.client.secret="team-b-client-secret" oauth.ssl.truststore.location="/tmp/truststore.p12" oauth.ssl.truststore.password="USDSTOREPASS" oauth.ssl.truststore.type="PKCS12" oauth.token.endpoint.uri="https://USDSSO_HOST/auth/realms/kafka-authz/protocol/openid-connect/token" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler EOF
USERNAME=alice PASSWORD=alice-password GRANT_RESPONSE=USD(curl -X POST "https://USDSSO_HOST/auth/realms/kafka-authz/protocol/openid-connect/token" -H 'Content-Type: application/x-www-form-urlencoded' -d "grant_type=password&username=USDUSERNAME&password=USDPASSWORD&client_id=kafka-cli&scope=offline_access" -s -k) REFRESH_TOKEN=USD(echo USDGRANT_RESPONSE | awk -F "refresh_token\":\"" '{printf USD2}' | awk -F "\"" '{printf USD1}')
cat > /tmp/alice.properties << EOF security.protocol=SASL_SSL ssl.truststore.location=/tmp/truststore.p12 ssl.truststore.password=USDSTOREPASS ssl.truststore.type=PKCS12 sasl.mechanism=OAUTHBEARER sasl.jaas.config=org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required oauth.refresh.token="USDREFRESH_TOKEN" oauth.client.id="kafka-cli" oauth.ssl.truststore.location="/tmp/truststore.p12" oauth.ssl.truststore.password="USDSTOREPASS" oauth.ssl.truststore.type="PKCS12" oauth.token.endpoint.uri="https://USDSSO_HOST/auth/realms/kafka-authz/protocol/openid-connect/token" ; sasl.login.callback.handler.class=io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler EOF
bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic my-topic --producer.config=/tmp/team-a-client.properties First message
bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic a_messages --producer.config /tmp/team-a-client.properties First message Second message
logs my-cluster-kafka-0 -f -n USDNS
bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic a_messages --from-beginning --consumer.config /tmp/team-a-client.properties
bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic a_messages --from-beginning --consumer.config /tmp/team-a-client.properties --group a_consumer_group_1
bin/kafka-topics.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/team-a-client.properties --list
bin/kafka-consumer-groups.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/team-a-client.properties --list
bin/kafka-configs.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/team-a-client.properties --entity-type brokers --describe --entity-default
bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic a_messages --producer.config /tmp/team-b-client.properties Message 1
bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic b_messages --producer.config /tmp/team-b-client.properties Message 1 Message 2 Message 3
bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages --producer.config /tmp/team-b-client.properties Message 1
bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages --producer.config /tmp/team-a-client.properties Message 1
bin/kafka-topics.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/alice.properties --topic x_messages --create --replication-factor 1 --partitions 1
bin/kafka-topics.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/alice.properties --list bin/kafka-topics.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/team-a-client.properties --list bin/kafka-topics.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/team-b-client.properties --list
bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages --producer.config /tmp/team-a-client.properties Message 1 Message 2 Message 3
bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages --producer.config /tmp/team-b-client.properties Message 4 Message 5
bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages --from-beginning --consumer.config /tmp/team-b-client.properties --group x_consumer_group_b
bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages --from-beginning --consumer.config /tmp/team-a-client.properties --group x_consumer_group_a
bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages --from-beginning --consumer.config /tmp/team-a-client.properties --group a_consumer_group_a
bin/kafka-console-consumer.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --topic x_messages --from-beginning --consumer.config /tmp/alice.properties
bin/kafka-configs.sh --bootstrap-server my-cluster-kafka-bootstrap:9093 --command-config /tmp/alice.properties --entity-type brokers --describe --entity-default