Chapter 4. Configuring persistent storage 4.1. Persistent storage using AWS Elastic Block Store OpenShift Container Platform supports AWS Elastic Block Store volumes (EBS). You can provision your OpenShift Container Platform cluster with persistent storage by using Amazon EC2 . Some familiarity with Kubernetes and AWS is assumed. The Kubernetes persistent volume framework allows administrators to provision a cluster with persistent storage and gives users a way to request those resources without having any knowledge of the underlying infrastructure. AWS Elastic Block Store volumes can be provisioned dynamically. Persistent volumes are not bound to a single project or namespace; they can be shared across the OpenShift Container Platform cluster. Persistent volume claims are specific to a project or namespace and can be requested by users. You can define a KMS key to encrypt container-persistent volumes on AWS. Important OpenShift Container Platform defaults to using an in-tree (non-CSI) plugin to provision AWS EBS storage. In future OpenShift Container Platform versions, volumes provisioned using existing in-tree plugins are planned for migration to their equivalent CSI driver. CSI automatic migration should be seamless. Migration does not change how you use all existing API objects, such as persistent volumes, persistent volume claims, and storage classes. For more information about migration, see CSI automatic migration . After full migration, in-tree plugins will eventually be removed in future versions of OpenShift Container Platform. Important High-availability of storage in the infrastructure is left to the underlying storage provider. For OpenShift Container Platform, automatic migration from AWS EBS in-tree to the Container Storage Interface (CSI) driver is available as a Technology Preview (TP) feature. With migration enabled, volumes provisioned using the existing in-tree driver are automatically migrated to use the AWS EBS CSI driver. For more information, see CSI automatic migration feature . 4.1.1. Creating the EBS storage class Storage classes are used to differentiate and delineate storage levels and usages. By defining a storage class, users can obtain dynamically provisioned persistent volumes. 4.1.2. Creating the persistent volume claim Prerequisites Storage must exist in the underlying infrastructure before it can be mounted as a volume in OpenShift Container Platform. Procedure In the OpenShift Container Platform console, click Storage Persistent Volume Claims . In the persistent volume claims overview, click Create Persistent Volume Claim . Define the desired options on the page that appears. Select the storage class created previously from the drop-down menu. Enter a unique name for the storage claim. Select the access mode. This determines the read and write access for the created storage claim. Define the size of the storage claim. Click Create to create the persistent volume claim and generate a persistent volume. 4.1.3. Volume format Before OpenShift Container Platform mounts the volume and passes it to a container, it checks that it contains a file system as specified by the fsType parameter in the persistent volume definition. If the device is not formatted with the file system, all data from the device is erased and the device is automatically formatted with the given file system. This allows using unformatted AWS volumes as persistent volumes, because OpenShift Container Platform formats them before the first use. 4.1.4. Maximum number of EBS volumes on a node By default, OpenShift Container Platform supports a maximum of 39 EBS volumes attached to one node. This limit is consistent with the AWS volume limits . The volume limit depends on the instance type. Important As a cluster administrator, you must use either in-tree or Container Storage Interface (CSI) volumes and their respective storage classes, but never both volume types at the same time. The maximum attached EBS volume number is counted separately for in-tree and CSI volumes. 4.1.5. Encrypting container persistent volumes on AWS with a KMS key Defining a KMS key to encrypt container-persistent volumes on AWS is useful when you have explicit compliance and security guidelines when deploying to AWS. Prerequisites Underlying infrastructure must contain storage. You must create a customer KMS key on AWS. Procedure Create a storage class: USD cat << EOF | oc create -f - apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: <storage-class-name> 1 parameters: fsType: ext4 2 encrypted: "true" kmsKeyId: keyvalue 3 provisioner: ebs.csi.aws.com reclaimPolicy: Delete volumeBindingMode: WaitForFirstConsumer EOF 1 Specifies the name of the storage class. 2 File system that is created on provisioned volumes. 3 Specifies the full Amazon Resource Name (ARN) of the key to use when encrypting the container-persistent volume. If you do not provide any key, but the encrypted field is set to true , then the default KMS key is used. See Finding the key ID and key ARN on AWS in the AWS documentation. Create a persistent volume claim (PVC) with the storage class specifying the KMS key: USD cat << EOF | oc create -f - apiVersion: v1 kind: PersistentVolumeClaim metadata: name: mypvc spec: accessModes: - ReadWriteOnce volumeMode: Filesystem storageClassName: <storage-class-name> resources: requests: storage: 1Gi EOF Create workload containers to consume the PVC: USD cat << EOF | oc create -f - kind: Pod metadata: name: mypod spec: containers: - name: httpd image: quay.io/centos7/httpd-24-centos7 ports: - containerPort: 80 volumeMounts: - mountPath: /mnt/storage name: data volumes: - name: data persistentVolumeClaim: claimName: mypvc EOF 4.1.6. Additional resources See AWS Elastic Block Store CSI Driver Operator for information about accessing additional storage options, such as volume snapshots, that are not possible with in-tree volume plugins. 4.2. Persistent storage using Azure OpenShift Container Platform supports Microsoft Azure Disk volumes. You can provision your OpenShift Container Platform cluster with persistent storage using Azure. Some familiarity with Kubernetes and Azure is assumed. The Kubernetes persistent volume framework allows administrators to provision a cluster with persistent storage and gives users a way to request those resources without having any knowledge of the underlying infrastructure. Azure Disk volumes can be provisioned dynamically. Persistent volumes are not bound to a single project or namespace; they can be shared across the OpenShift Container Platform cluster. Persistent volume claims are specific to a project or namespace and can be requested by users. Important OpenShift Container Platform defaults to using an in-tree (non-CSI) plugin to provision Azure Disk storage. In future OpenShift Container Platform versions, volumes provisioned using existing in-tree plugins are planned for migration to their equivalent CSI driver. CSI automatic migration should be seamless. Migration does not change how you use all existing API objects, such as persistent volumes, persistent volume claims, and storage classes. For more information about migration, see CSI automatic migration . After full migration, in-tree plugins will eventually be removed in future versions of OpenShift Container Platform. Important High availability of storage in the infrastructure is left to the underlying storage provider. Additional resources Microsoft Azure Disk 4.2.1. Creating the Azure storage class Storage classes are used to differentiate and delineate storage levels and usages. By defining a storage class, users can obtain dynamically provisioned persistent volumes. Procedure In the OpenShift Container Platform console, click Storage Storage Classes . In the storage class overview, click Create Storage Class . Define the desired options on the page that appears. Enter a name to reference the storage class. Enter an optional description. Select the reclaim policy. Select kubernetes.io/azure-disk from the drop down list. Enter the storage account type. This corresponds to your Azure storage account SKU tier. Valid options are Premium_LRS , Standard_LRS , StandardSSD_LRS , and UltraSSD_LRS . Enter the kind of account. Valid options are shared , dedicated, and managed . Important Red Hat only supports the use of kind: Managed in the storage class. With Shared and Dedicated , Azure creates unmanaged disks, while OpenShift Container Platform creates a managed disk for machine OS (root) disks. But because Azure Disk does not allow the use of both managed and unmanaged disks on a node, unmanaged disks created with Shared or Dedicated cannot be attached to OpenShift Container Platform nodes. Enter additional parameters for the storage class as desired. Click Create to create the storage class. Additional resources Azure Disk Storage Class 4.2.2. Creating the persistent volume claim Prerequisites Storage must exist in the underlying infrastructure before it can be mounted as a volume in OpenShift Container Platform. Procedure In the OpenShift Container Platform console, click Storage Persistent Volume Claims . In the persistent volume claims overview, click Create Persistent Volume Claim . Define the desired options on the page that appears. Select the storage class created previously from the drop-down menu. Enter a unique name for the storage claim. Select the access mode. This determines the read and write access for the created storage claim. Define the size of the storage claim. Click Create to create the persistent volume claim and generate a persistent volume. 4.2.3. Volume format Before OpenShift Container Platform mounts the volume and passes it to a container, it checks that it contains a file system as specified by the fsType parameter in the persistent volume definition. If the device is not formatted with the file system, all data from the device is erased and the device is automatically formatted with the given file system. This allows using unformatted Azure volumes as persistent volumes, because OpenShift Container Platform formats them before the first use. 4.2.4. Machine sets that deploy machines with ultra disks using PVCs You can create a machine set running on Azure that deploys machines with ultra disks. Ultra disks are high-performance storage that are intended for use with the most demanding data workloads. Both the in-tree plugin and CSI driver support using PVCs to enable ultra disks. You can also deploy machines with ultra disks as data disks without creating a PVC. Additional resources Microsoft Azure ultra disks documentation Machine sets that deploy machines on ultra disks using CSI PVCs Machine sets that deploy machines on ultra disks as data disks 4.2.4.1. Creating machines with ultra disks by using machine sets You can deploy machines with ultra disks on Azure by editing your machine set YAML file. Prerequisites Have an existing Microsoft Azure cluster. Procedure Copy an existing Azure MachineSet custom resource (CR) and edit it by running the following command: USD oc edit machineset <machine-set-name> where <machine-set-name> is the machine set that you want to provision machines with ultra disks. Add the following lines in the positions indicated: apiVersion: machine.openshift.io/v1beta1 kind: MachineSet ... spec: ... template: ... spec: metadata: ... labels: ... disk: ultrassd 1 ... providerSpec: value: ... ultraSSDCapability: Enabled 2 ... 1 Specify a label to use to select a node that is created by this machine set. This procedure uses disk.ultrassd for this value. 2 These lines enable the use of ultra disks. Create a machine set using the updated configuration by running the following command: USD oc create -f <machine-set-name>.yaml Create a storage class that contains the following YAML definition: apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: ultra-disk-sc 1 parameters: cachingMode: None diskIopsReadWrite: "2000" 2 diskMbpsReadWrite: "320" 3 kind: managed skuname: UltraSSD_LRS provisioner: disk.csi.azure.com 4 reclaimPolicy: Delete volumeBindingMode: WaitForFirstConsumer 5 1 Specify the name of the storage class. This procedure uses ultra-disk-sc for this value. 2 Specify the number of IOPS for the storage class. 3 Specify the throughput in MBps for the storage class. 4 For Azure Kubernetes Service (AKS) version 1.21 or later, use disk.csi.azure.com . For earlier versions of AKS, use kubernetes.io/azure-disk . 5 Optional: Specify this parameter to wait for the creation of the pod that will use the disk. Create a persistent volume claim (PVC) to reference the ultra-disk-sc storage class that contains the following YAML definition: apiVersion: v1 kind: PersistentVolumeClaim metadata: name: ultra-disk 1 spec: accessModes: - ReadWriteOnce storageClassName: ultra-disk-sc 2 resources: requests: storage: 4Gi 3 1 Specify the name of the PVC. This procedure uses ultra-disk for this value. 2 This PVC references the ultra-disk-sc storage class. 3 Specify the size for the storage class. The minimum value is 4Gi . Create a pod that contains the following YAML definition: apiVersion: v1 kind: Pod metadata: name: nginx-ultra spec: nodeSelector: disk: ultrassd 1 containers: - name: nginx-ultra image: alpine:latest command: - "sleep" - "infinity" volumeMounts: - mountPath: "/mnt/azure" name: volume volumes: - name: volume persistentVolumeClaim: claimName: ultra-disk 2 1 Specify the label of the machine set that enables the use of ultra disks. This procedure uses disk.ultrassd for this value. 2 This pod references the ultra-disk PVC. Verification Validate that the machines are created by running the following command: USD oc get machines The machines should be in the Running state. For a machine that is running and has a node attached, validate the partition by running the following command: USD oc debug node/<node-name> -- chroot /host lsblk In this command, oc debug node/<node-name> starts a debugging shell on the node <node-name> and passes a command with -- . The passed command chroot /host provides access to the underlying host OS binaries, and lsblk shows the block devices that are attached to the host OS machine. steps To use an ultra disk from within a pod, create workload that uses the mount point. Create a YAML file similar to the following example: apiVersion: v1 kind: Pod metadata: name: ssd-benchmark1 spec: containers: - name: ssd-benchmark1 image: nginx ports: - containerPort: 80 name: "http-server" volumeMounts: - name: lun0p1 mountPath: "/tmp" volumes: - name: lun0p1 hostPath: path: /var/lib/lun0p1 type: DirectoryOrCreate nodeSelector: disktype: ultrassd 4.2.4.2. Troubleshooting resources for machine sets that enable ultra disks Use the information in this section to understand and recover from issues you might encounter. 4.2.4.2.1. Unable to mount a persistent volume claim backed by an ultra disk If there is an issue mounting a persistent volume claim backed by an ultra disk, the pod becomes stuck in the ContainerCreating state and an alert is triggered. For example, if the additionalCapabilities.ultraSSDEnabled parameter is not set on the machine that backs the node that hosts the pod, the following error message appears: StorageAccountType UltraSSD_LRS can be used only when additionalCapabilities.ultraSSDEnabled is set. To resolve this issue, describe the pod by running the following command: USD oc -n <stuck_pod_namespace> describe pod <stuck_pod_name> 4.3. Persistent storage using Azure File OpenShift Container Platform supports Microsoft Azure File volumes. You can provision your OpenShift Container Platform cluster with persistent storage using Azure. Some familiarity with Kubernetes and Azure is assumed. The Kubernetes persistent volume framework allows administrators to provision a cluster with persistent storage and gives users a way to request those resources without having any knowledge of the underlying infrastructure. You can provision Azure File volumes dynamically. Persistent volumes are not bound to a single project or namespace, and you can share them across the OpenShift Container Platform cluster. Persistent volume claims are specific to a project or namespace, and can be requested by users for use in applications. Important High availability of storage in the infrastructure is left to the underlying storage provider. Important Azure File volumes use Server Message Block. Important In future OpenShift Container Platform versions, volumes provisioned using existing in-tree plugins are planned for migration to their equivalent CSI driver. CSI automatic migration should be seamless. Migration does not change how you use all existing API objects, such as persistent volumes, persistent volume claims, and storage classes. For more information about migration, see CSI automatic migration . After full migration, in-tree plugins will eventually be removed in future versions of OpenShift Container Platform. Additional resources Azure Files 4.3.1. Create the Azure File share persistent volume claim To create the persistent volume claim, you must first define a Secret object that contains the Azure account and key. This secret is used in the PersistentVolume definition, and will be referenced by the persistent volume claim for use in applications. Prerequisites An Azure File share exists. The credentials to access this share, specifically the storage account and key, are available. Procedure Create a Secret object that contains the Azure File credentials: USD oc create secret generic <secret-name> --from-literal=azurestorageaccountname=<storage-account> \ 1 --from-literal=azurestorageaccountkey=<storage-account-key> 2 1 The Azure File storage account name. 2 The Azure File storage account key. Create a PersistentVolume object that references the Secret object you created: apiVersion: "v1" kind: "PersistentVolume" metadata: name: "pv0001" 1 spec: capacity: storage: "5Gi" 2 accessModes: - "ReadWriteOnce" storageClassName: azure-file-sc azureFile: secretName: <secret-name> 3 shareName: share-1 4 readOnly: false 1 The name of the persistent volume. 2 The size of this persistent volume. 3 The name of the secret that contains the Azure File share credentials. 4 The name of the Azure File share. Create a PersistentVolumeClaim object that maps to the persistent volume you created: apiVersion: "v1" kind: "PersistentVolumeClaim" metadata: name: "claim1" 1 spec: accessModes: - "ReadWriteOnce" resources: requests: storage: "5Gi" 2 storageClassName: azure-file-sc 3 volumeName: "pv0001" 4 1 The name of the persistent volume claim. 2 The size of this persistent volume claim. 3 The name of the storage class that is used to provision the persistent volume. Specify the storage class used in the PersistentVolume definition. 4 The name of the existing PersistentVolume object that references the Azure File share. 4.3.2. Mount the Azure File share in a pod After the persistent volume claim has been created, it can be used inside by an application. The following example demonstrates mounting this share inside of a pod. Prerequisites A persistent volume claim exists that is mapped to the underlying Azure File share. Procedure Create a pod that mounts the existing persistent volume claim: apiVersion: v1 kind: Pod metadata: name: pod-name 1 spec: containers: ... volumeMounts: - mountPath: "/data" 2 name: azure-file-share volumes: - name: azure-file-share persistentVolumeClaim: claimName: claim1 3 1 The name of the pod. 2 The path to mount the Azure File share inside the pod. Do not mount to the container root, / , or any path that is the same in the host and the container. This can corrupt your host system if the container is sufficiently privileged, such as the host /dev/pts files. It is safe to mount the host by using /host . 3 The name of the PersistentVolumeClaim object that has been previously created. 4.4. Persistent storage using Cinder OpenShift Container Platform supports OpenStack Cinder. Some familiarity with Kubernetes and OpenStack is assumed. Cinder volumes can be provisioned dynamically. Persistent volumes are not bound to a single project or namespace; they can be shared across the OpenShift Container Platform cluster. Persistent volume claims are specific to a project or namespace and can be requested by users. Important OpenShift Container Platform defaults to using an in-tree (non-CSI) plugin to provision Cinder storage. In future OpenShift Container Platform versions, volumes provisioned using existing in-tree plugins are planned for migration to their equivalent CSI driver. CSI automatic migration should be seamless. Migration does not change how you use all existing API objects, such as persistent volumes, persistent volume claims, and storage classes. For more information about migration, see CSI automatic migration . After full migration, in-tree plugins will eventually be removed in future versions of OpenShift Container Platform. Additional resources For more information about how OpenStack Block Storage provides persistent block storage management for virtual hard drives, see OpenStack Cinder . 4.4.1. Manual provisioning with Cinder Storage must exist in the underlying infrastructure before it can be mounted as a volume in OpenShift Container Platform. Prerequisites OpenShift Container Platform configured for Red Hat OpenStack Platform (RHOSP) Cinder volume ID 4.4.1.1. Creating the persistent volume You must define your persistent volume (PV) in an object definition before creating it in OpenShift Container Platform: Procedure Save your object definition to a file. cinder-persistentvolume.yaml apiVersion: "v1" kind: "PersistentVolume" metadata: name: "pv0001" 1 spec: capacity: storage: "5Gi" 2 accessModes: - "ReadWriteOnce" cinder: 3 fsType: "ext3" 4 volumeID: "f37a03aa-6212-4c62-a805-9ce139fab180" 5 1 The name of the volume that is used by persistent volume claims or pods. 2 The amount of storage allocated to this volume. 3 Indicates cinder for Red Hat OpenStack Platform (RHOSP) Cinder volumes. 4 The file system that is created when the volume is mounted for the first time. 5 The Cinder volume to use. Important Do not change the fstype parameter value after the volume is formatted and provisioned. Changing this value can result in data loss and pod failure. Create the object definition file you saved in the step. USD oc create -f cinder-persistentvolume.yaml 4.4.1.2. Persistent volume formatting You can use unformatted Cinder volumes as PVs because OpenShift Container Platform formats them before the first use. Before OpenShift Container Platform mounts the volume and passes it to a container, the system checks that it contains a file system as specified by the fsType parameter in the PV definition. If the device is not formatted with the file system, all data from the device is erased and the device is automatically formatted with the given file system. 4.4.1.3. Cinder volume security If you use Cinder PVs in your application, configure security for their deployment configurations. Prerequisites An SCC must be created that uses the appropriate fsGroup strategy. Procedure Create a service account and add it to the SCC: USD oc create serviceaccount <service_account> USD oc adm policy add-scc-to-user <new_scc> -z <service_account> -n <project> In your application's deployment configuration, provide the service account name and securityContext : apiVersion: v1 kind: ReplicationController metadata: name: frontend-1 spec: replicas: 1 1 selector: 2 name: frontend template: 3 metadata: labels: 4 name: frontend 5 spec: containers: - image: openshift/hello-openshift name: helloworld ports: - containerPort: 8080 protocol: TCP restartPolicy: Always serviceAccountName: <service_account> 6 securityContext: fsGroup: 7777 7 1 The number of copies of the pod to run. 2 The label selector of the pod to run. 3 A template for the pod that the controller creates. 4 The labels on the pod. They must include labels from the label selector. 5 The maximum name length after expanding any parameters is 63 characters. 6 Specifies the service account you created. 7 Specifies an fsGroup for the pods. 4.5. Persistent storage using Fibre Channel OpenShift Container Platform supports Fibre Channel, allowing you to provision your OpenShift Container Platform cluster with persistent storage using Fibre channel volumes. Some familiarity with Kubernetes and Fibre Channel is assumed. Important Persistent storage using Fibre Channel is not supported on ARM architecture based infrastructures. The Kubernetes persistent volume framework allows administrators to provision a cluster with persistent storage and gives users a way to request those resources without having any knowledge of the underlying infrastructure. Persistent volumes are not bound to a single project or namespace; they can be shared across the OpenShift Container Platform cluster. Persistent volume claims are specific to a project or namespace and can be requested by users. Important High availability of storage in the infrastructure is left to the underlying storage provider. Additional resources Using Fibre Channel devices 4.5.1. Provisioning To provision Fibre Channel volumes using the PersistentVolume API the following must be available: The targetWWNs (array of Fibre Channel target's World Wide Names). A valid LUN number. The filesystem type. A persistent volume and a LUN have a one-to-one mapping between them. Prerequisites Fibre Channel LUNs must exist in the underlying infrastructure. PersistentVolume object definition apiVersion: v1 kind: PersistentVolume metadata: name: pv0001 spec: capacity: storage: 1Gi accessModes: - ReadWriteOnce fc: wwids: [scsi-3600508b400105e210000900000490000] 1 targetWWNs: ['500a0981891b8dc5', '500a0981991b8dc5'] 2 lun: 2 3 fsType: ext4 1 World wide identifiers (WWIDs). Either FC wwids or a combination of FC targetWWNs and lun must be set, but not both simultaneously. The FC WWID identifier is recommended over the WWNs target because it is guaranteed to be unique for every storage device, and independent of the path that is used to access the device. The WWID identifier can be obtained by issuing a SCSI Inquiry to retrieve the Device Identification Vital Product Data ( page 0x83 ) or Unit Serial Number ( page 0x80 ). FC WWIDs are identified as /dev/disk/by-id/ to reference the data on the disk, even if the path to the device changes and even when accessing the device from different systems. 2 3 Fibre Channel WWNs are identified as /dev/disk/by-path/pci-<IDENTIFIER>-fc-0x<WWN>-lun-<LUN#> , but you do not need to provide any part of the path leading up to the WWN , including the 0x , and anything after, including the - (hyphen). Important Changing the value of the fstype parameter after the volume has been formatted and provisioned can result in data loss and pod failure. 4.5.1.1. Enforcing disk quotas Use LUN partitions to enforce disk quotas and size constraints. Each LUN is mapped to a single persistent volume, and unique names must be used for persistent volumes. Enforcing quotas in this way allows the end user to request persistent storage by a specific amount, such as 10Gi, and be matched with a corresponding volume of equal or greater capacity. 4.5.1.2. Fibre Channel volume security Users request storage with a persistent volume claim. This claim only lives in the user's namespace, and can only be referenced by a pod within that same namespace. Any attempt to access a persistent volume across a namespace causes the pod to fail. Each Fibre Channel LUN must be accessible by all nodes in the cluster. 4.6. Persistent storage using FlexVolume Important FlexVolume is a deprecated feature. Deprecated functionality is still included in OpenShift Container Platform and continues to be supported; however, it will be removed in a future release of this product and is not recommended for new deployments. Out-of-tree Container Storage Interface (CSI) driver is the recommended way to write volume drivers in OpenShift Container Platform. Maintainers of FlexVolume drivers should implement a CSI driver and move users of FlexVolume to CSI. Users of FlexVolume should move their workloads to CSI driver. For the most recent list of major functionality that has been deprecated or removed within OpenShift Container Platform, refer to the Deprecated and removed features section of the OpenShift Container Platform release notes. OpenShift Container Platform supports FlexVolume, an out-of-tree plugin that uses an executable model to interface with drivers. To use storage from a back-end that does not have a built-in plugin, you can extend OpenShift Container Platform through FlexVolume drivers and provide persistent storage to applications. Pods interact with FlexVolume drivers through the flexvolume in-tree plugin. Additional resources Expanding persistent volumes 4.6.1. About FlexVolume drivers A FlexVolume driver is an executable file that resides in a well-defined directory on all nodes in the cluster. OpenShift Container Platform calls the FlexVolume driver whenever it needs to mount or unmount a volume represented by a PersistentVolume object with flexVolume as the source. Important Attach and detach operations are not supported in OpenShift Container Platform for FlexVolume. 4.6.2. FlexVolume driver example The first command-line argument of the FlexVolume driver is always an operation name. Other parameters are specific to each operation. Most of the operations take a JavaScript Object Notation (JSON) string as a parameter. This parameter is a complete JSON string, and not the name of a file with the JSON data. The FlexVolume driver contains: All flexVolume.options . Some options from flexVolume prefixed by kubernetes.io/ , such as fsType and readwrite . The content of the referenced secret, if specified, prefixed by kubernetes.io/secret/ . FlexVolume driver JSON input example { "fooServer": "192.168.0.1:1234", 1 "fooVolumeName": "bar", "kubernetes.io/fsType": "ext4", 2 "kubernetes.io/readwrite": "ro", 3 "kubernetes.io/secret/<key name>": "<key value>", 4 "kubernetes.io/secret/<another key name>": "<another key value>", } 1 All options from flexVolume.options . 2 The value of flexVolume.fsType . 3 ro / rw based on flexVolume.readOnly . 4 All keys and their values from the secret referenced by flexVolume.secretRef . OpenShift Container Platform expects JSON data on standard output of the driver. When not specified, the output describes the result of the operation. FlexVolume driver default output example { "status": "<Success/Failure/Not supported>", "message": "<Reason for success/failure>" } Exit code of the driver should be 0 for success and 1 for error. Operations should be idempotent, which means that the mounting of an already mounted volume should result in a successful operation. 4.6.3. Installing FlexVolume drivers FlexVolume drivers that are used to extend OpenShift Container Platform are executed only on the node. To implement FlexVolumes, a list of operations to call and the installation path are all that is required. Prerequisites FlexVolume drivers must implement these operations: init Initializes the driver. It is called during initialization of all nodes. Arguments: none Executed on: node Expected output: default JSON mount Mounts a volume to directory. This can include anything that is necessary to mount the volume, including finding the device and then mounting the device. Arguments: <mount-dir> <json> Executed on: node Expected output: default JSON unmount Unmounts a volume from a directory. This can include anything that is necessary to clean up the volume after unmounting. Arguments: <mount-dir> Executed on: node Expected output: default JSON mountdevice Mounts a volume's device to a directory where individual pods can then bind mount. This call-out does not pass "secrets" specified in the FlexVolume spec. If your driver requires secrets, do not implement this call-out. Arguments: <mount-dir> <json> Executed on: node Expected output: default JSON unmountdevice Unmounts a volume's device from a directory. Arguments: <mount-dir> Executed on: node Expected output: default JSON All other operations should return JSON with {"status": "Not supported"} and exit code 1 . Procedure To install the FlexVolume driver: Ensure that the executable file exists on all nodes in the cluster. Place the executable file at the volume plugin path: /etc/kubernetes/kubelet-plugins/volume/exec/<vendor>~<driver>/<driver> . For example, to install the FlexVolume driver for the storage foo , place the executable file at: /etc/kubernetes/kubelet-plugins/volume/exec/openshift.com~foo/foo . 4.6.4. Consuming storage using FlexVolume drivers Each PersistentVolume object in OpenShift Container Platform represents one storage asset in the storage back-end, such as a volume. Procedure Use the PersistentVolume object to reference the installed storage. Persistent volume object definition using FlexVolume drivers example apiVersion: v1 kind: PersistentVolume metadata: name: pv0001 1 spec: capacity: storage: 1Gi 2 accessModes: - ReadWriteOnce flexVolume: driver: openshift.com/foo 3 fsType: "ext4" 4 secretRef: foo-secret 5 readOnly: true 6 options: 7 fooServer: 192.168.0.1:1234 fooVolumeName: bar 1 The name of the volume. This is how it is identified through persistent volume claims or from pods. This name can be different from the name of the volume on back-end storage. 2 The amount of storage allocated to this volume. 3 The name of the driver. This field is mandatory. 4 The file system that is present on the volume. This field is optional. 5 The reference to a secret. Keys and values from this secret are provided to the FlexVolume driver on invocation. This field is optional. 6 The read-only flag. This field is optional. 7 The additional options for the FlexVolume driver. In addition to the flags specified by the user in the options field, the following flags are also passed to the executable: Note Secrets are passed only to mount or unmount call-outs. 4.7. Persistent storage using GCE Persistent Disk OpenShift Container Platform supports GCE Persistent Disk volumes (gcePD). You can provision your OpenShift Container Platform cluster with persistent storage using GCE. Some familiarity with Kubernetes and GCE is assumed. The Kubernetes persistent volume framework allows administrators to provision a cluster with persistent storage and gives users a way to request those resources without having any knowledge of the underlying infrastructure. GCE Persistent Disk volumes can be provisioned dynamically. Persistent volumes are not bound to a single project or namespace; they can be shared across the OpenShift Container Platform cluster. Persistent volume claims are specific to a project or namespace and can be requested by users. Important OpenShift Container Platform defaults to using an in-tree (non-CSI) plugin to provision gcePD storage. In future OpenShift Container Platform versions, volumes provisioned using existing in-tree plugins are planned for migration to their equivalent CSI driver. CSI automatic migration should be seamless. Migration does not change how you use all existing API objects, such as persistent volumes, persistent volume claims, and storage classes. For more information about migration, see CSI automatic migration . After full migration, in-tree plugins will eventually be removed in future versions of OpenShift Container Platform. Important High availability of storage in the infrastructure is left to the underlying storage provider. Additional resources GCE Persistent Disk 4.7.1. Creating the GCE storage class Storage classes are used to differentiate and delineate storage levels and usages. By defining a storage class, users can obtain dynamically provisioned persistent volumes. 4.7.2. Creating the persistent volume claim Prerequisites Storage must exist in the underlying infrastructure before it can be mounted as a volume in OpenShift Container Platform. Procedure In the OpenShift Container Platform console, click Storage Persistent Volume Claims . In the persistent volume claims overview, click Create Persistent Volume Claim . Define the desired options on the page that appears. Select the storage class created previously from the drop-down menu. Enter a unique name for the storage claim. Select the access mode. This determines the read and write access for the created storage claim. Define the size of the storage claim. Click Create to create the persistent volume claim and generate a persistent volume. 4.7.3. Volume format Before OpenShift Container Platform mounts the volume and passes it to a container, it checks that it contains a file system as specified by the fsType parameter in the persistent volume definition. If the device is not formatted with the file system, all data from the device is erased and the device is automatically formatted with the given file system. This allows using unformatted GCE volumes as persistent volumes, because OpenShift Container Platform formats them before the first use. 4.8. Persistent storage using hostPath A hostPath volume in an OpenShift Container Platform cluster mounts a file or directory from the host node's filesystem into your pod. Most pods will not need a hostPath volume, but it does offer a quick option for testing should an application require it. Important The cluster administrator must configure pods to run as privileged. This grants access to pods in the same node. 4.8.1. Overview OpenShift Container Platform supports hostPath mounting for development and testing on a single-node cluster. In a production cluster, you would not use hostPath. Instead, a cluster administrator would provision a network resource, such as a GCE Persistent Disk volume, an NFS share, or an Amazon EBS volume. Network resources support the use of storage classes to set up dynamic provisioning. A hostPath volume must be provisioned statically. Important Do not mount to the container root, / , or any path that is the same in the host and the container. This can corrupt your host system if the container is sufficiently privileged. It is safe to mount the host by using /host . The following example shows the / directory from the host being mounted into the container at /host . apiVersion: v1 kind: Pod metadata: name: test-host-mount spec: containers: - image: registry.access.redhat.com/ubi8/ubi name: test-container command: ['sh', '-c', 'sleep 3600'] volumeMounts: - mountPath: /host name: host-slash volumes: - name: host-slash hostPath: path: / type: '' 4.8.2. Statically provisioning hostPath volumes A pod that uses a hostPath volume must be referenced by manual (static) provisioning. Procedure Define the persistent volume (PV). Create a file, pv.yaml , with the PersistentVolume object definition: apiVersion: v1 kind: PersistentVolume metadata: name: task-pv-volume 1 labels: type: local spec: storageClassName: manual 2 capacity: storage: 5Gi accessModes: - ReadWriteOnce 3 persistentVolumeReclaimPolicy: Retain hostPath: path: "/mnt/data" 4 1 The name of the volume. This name is how it is identified by persistent volume claims or pods. 2 Used to bind persistent volume claim requests to this persistent volume. 3 The volume can be mounted as read-write by a single node. 4 The configuration file specifies that the volume is at /mnt/data on the cluster's node. Do not mount to the container root, / , or any path that is the same in the host and the container. This can corrupt your host system. It is safe to mount the host by using /host . Create the PV from the file: USD oc create -f pv.yaml Define the persistent volume claim (PVC). Create a file, pvc.yaml , with the PersistentVolumeClaim object definition: apiVersion: v1 kind: PersistentVolumeClaim metadata: name: task-pvc-volume spec: accessModes: - ReadWriteOnce resources: requests: storage: 1Gi storageClassName: manual Create the PVC from the file: USD oc create -f pvc.yaml 4.8.3. Mounting the hostPath share in a privileged pod After the persistent volume claim has been created, it can be used inside by an application. The following example demonstrates mounting this share inside of a pod. Prerequisites A persistent volume claim exists that is mapped to the underlying hostPath share. Procedure Create a privileged pod that mounts the existing persistent volume claim: apiVersion: v1 kind: Pod metadata: name: pod-name 1 spec: containers: ... securityContext: privileged: true 2 volumeMounts: - mountPath: /data 3 name: hostpath-privileged ... securityContext: {} volumes: - name: hostpath-privileged persistentVolumeClaim: claimName: task-pvc-volume 4 1 The name of the pod. 2 The pod must run as privileged to access the node's storage. 3 The path to mount the host path share inside the privileged pod. Do not mount to the container root, / , or any path that is the same in the host and the container. This can corrupt your host system if the container is sufficiently privileged, such as the host /dev/pts files. It is safe to mount the host by using /host . 4 The name of the PersistentVolumeClaim object that has been previously created. 4.9. Persistent storage using iSCSI You can provision your OpenShift Container Platform cluster with persistent storage using iSCSI . Some familiarity with Kubernetes and iSCSI is assumed. The Kubernetes persistent volume framework allows administrators to provision a cluster with persistent storage and gives users a way to request those resources without having any knowledge of the underlying infrastructure. Important High-availability of storage in the infrastructure is left to the underlying storage provider. Important When you use iSCSI on Amazon Web Services, you must update the default security policy to include TCP traffic between nodes on the iSCSI ports. By default, they are ports 860 and 3260 . Important Users must ensure that the iSCSI initiator is already configured on all OpenShift Container Platform nodes by installing the iscsi-initiator-utils package and configuring their initiator name in /etc/iscsi/initiatorname.iscsi . The iscsi-initiator-utils package is already installed on deployments that use Red Hat Enterprise Linux CoreOS (RHCOS). For more information, see Managing Storage Devices . 4.9.1. Provisioning Verify that the storage exists in the underlying infrastructure before mounting it as a volume in OpenShift Container Platform. All that is required for the iSCSI is the iSCSI target portal, a valid iSCSI Qualified Name (IQN), a valid LUN number, the filesystem type, and the PersistentVolume API. PersistentVolume object definition apiVersion: v1 kind: PersistentVolume metadata: name: iscsi-pv spec: capacity: storage: 1Gi accessModes: - ReadWriteOnce iscsi: targetPortal: 10.16.154.81:3260 iqn: iqn.2014-12.example.server:storage.target00 lun: 0 fsType: 'ext4' 4.9.2. Enforcing disk quotas Use LUN partitions to enforce disk quotas and size constraints. Each LUN is one persistent volume. Kubernetes enforces unique names for persistent volumes. Enforcing quotas in this way allows the end user to request persistent storage by a specific amount (for example, 10Gi ) and be matched with a corresponding volume of equal or greater capacity. 4.9.3. iSCSI volume security Users request storage with a PersistentVolumeClaim object. This claim only lives in the user's namespace and can only be referenced by a pod within that same namespace. Any attempt to access a persistent volume claim across a namespace causes the pod to fail. Each iSCSI LUN must be accessible by all nodes in the cluster. 4.9.3.1. Challenge Handshake Authentication Protocol (CHAP) configuration Optionally, OpenShift Container Platform can use CHAP to authenticate itself to iSCSI targets: apiVersion: v1 kind: PersistentVolume metadata: name: iscsi-pv spec: capacity: storage: 1Gi accessModes: - ReadWriteOnce iscsi: targetPortal: 10.0.0.1:3260 iqn: iqn.2016-04.test.com:storage.target00 lun: 0 fsType: ext4 chapAuthDiscovery: true 1 chapAuthSession: true 2 secretRef: name: chap-secret 3 1 Enable CHAP authentication of iSCSI discovery. 2 Enable CHAP authentication of iSCSI session. 3 Specify name of Secrets object with user name + password. This Secret object must be available in all namespaces that can use the referenced volume. 4.9.4. iSCSI multipathing For iSCSI-based storage, you can configure multiple paths by using the same IQN for more than one target portal IP address. Multipathing ensures access to the persistent volume when one or more of the components in a path fail. To specify multi-paths in the pod specification, use the portals field. For example: apiVersion: v1 kind: PersistentVolume metadata: name: iscsi-pv spec: capacity: storage: 1Gi accessModes: - ReadWriteOnce iscsi: targetPortal: 10.0.0.1:3260 portals: ['10.0.2.16:3260', '10.0.2.17:3260', '10.0.2.18:3260'] 1 iqn: iqn.2016-04.test.com:storage.target00 lun: 0 fsType: ext4 readOnly: false 1 Add additional target portals using the portals field. 4.9.5. iSCSI custom initiator IQN Configure the custom initiator iSCSI Qualified Name (IQN) if the iSCSI targets are restricted to certain IQNs, but the nodes that the iSCSI PVs are attached to are not guaranteed to have these IQNs. To specify a custom initiator IQN, use initiatorName field. apiVersion: v1 kind: PersistentVolume metadata: name: iscsi-pv spec: capacity: storage: 1Gi accessModes: - ReadWriteOnce iscsi: targetPortal: 10.0.0.1:3260 portals: ['10.0.2.16:3260', '10.0.2.17:3260', '10.0.2.18:3260'] iqn: iqn.2016-04.test.com:storage.target00 lun: 0 initiatorName: iqn.2016-04.test.com:custom.iqn 1 fsType: ext4 readOnly: false 1 Specify the name of the initiator. 4.10. Persistent storage using local volumes OpenShift Container Platform can be provisioned with persistent storage by using local volumes. Local persistent volumes allow you to access local storage devices, such as a disk or partition, by using the standard persistent volume claim interface. Local volumes can be used without manually scheduling pods to nodes because the system is aware of the volume node constraints. However, local volumes are still subject to the availability of the underlying node and are not suitable for all applications. Note Local volumes can only be used as a statically created persistent volume. 4.10.1. Installing the Local Storage Operator The Local Storage Operator is not installed in OpenShift Container Platform by default. Use the following procedure to install and configure this Operator to enable local volumes in your cluster. Prerequisites Access to the OpenShift Container Platform web console or command-line interface (CLI). Procedure Create the openshift-local-storage project: USD oc adm new-project openshift-local-storage Optional: Allow local storage creation on infrastructure nodes. You might want to use the Local Storage Operator to create volumes on infrastructure nodes in support of components such as logging and monitoring. You must adjust the default node selector so that the Local Storage Operator includes the infrastructure nodes, and not just worker nodes. To block the Local Storage Operator from inheriting the cluster-wide default selector, enter the following command: USD oc annotate namespace openshift-local-storage openshift.io/node-selector='' Optional: Allow local storage to run on the management pool of CPUs in single-node deployment. Use the Local Storage Operator in single-node deployments and allow the use of CPUs that belong to the management pool. Perform this step on single-node installations that use management workload partitioning. To allow Local Storage Operator to run on the management CPU pool, run following commands: USD oc annotate namespace openshift-local-storage workload.openshift.io/allowed='management' From the UI To install the Local Storage Operator from the web console, follow these steps: Log in to the OpenShift Container Platform web console. Navigate to Operators OperatorHub . Type Local Storage into the filter box to locate the Local Storage Operator. Click Install . On the Install Operator page, select A specific namespace on the cluster . Select openshift-local-storage from the drop-down menu. Adjust the values for Update Channel and Approval Strategy to the values that you want. Click Install . Once finished, the Local Storage Operator will be listed in the Installed Operators section of the web console. From the CLI Install the Local Storage Operator from the CLI. Create an object YAML file to define an Operator group and subscription for the Local Storage Operator, such as openshift-local-storage.yaml : Example openshift-local-storage.yaml apiVersion: operators.coreos.com/v1 kind: OperatorGroup metadata: name: local-operator-group namespace: openshift-local-storage spec: targetNamespaces: - openshift-local-storage --- apiVersion: operators.coreos.com/v1alpha1 kind: Subscription metadata: name: local-storage-operator namespace: openshift-local-storage spec: channel: stable installPlanApproval: Automatic 1 name: local-storage-operator source: redhat-operators sourceNamespace: openshift-marketplace 1 The user approval policy for an install plan. Create the Local Storage Operator object by entering the following command: USD oc apply -f openshift-local-storage.yaml At this point, the Operator Lifecycle Manager (OLM) is now aware of the Local Storage Operator. A ClusterServiceVersion (CSV) for the Operator should appear in the target namespace, and APIs provided by the Operator should be available for creation. Verify local storage installation by checking that all pods and the Local Storage Operator have been created: Check that all the required pods have been created: USD oc -n openshift-local-storage get pods Example output NAME READY STATUS RESTARTS AGE local-storage-operator-746bf599c9-vlt5t 1/1 Running 0 19m Check the ClusterServiceVersion (CSV) YAML manifest to see that the Local Storage Operator is available in the openshift-local-storage project: USD oc get csvs -n openshift-local-storage Example output NAME DISPLAY VERSION REPLACES PHASE local-storage-operator.4.2.26-202003230335 Local Storage 4.2.26-202003230335 Succeeded After all checks have passed, the Local Storage Operator is installed successfully. 4.10.2. Provisioning local volumes by using the Local Storage Operator Local volumes cannot be created by dynamic provisioning. Instead, persistent volumes can be created by the Local Storage Operator. The local volume provisioner looks for any file system or block volume devices at the paths specified in the defined resource. Prerequisites The Local Storage Operator is installed. You have a local disk that meets the following conditions: It is attached to a node. It is not mounted. It does not contain partitions. Procedure Create the local volume resource. This resource must define the nodes and paths to the local volumes. Note Do not use different storage class names for the same device. Doing so will create multiple persistent volumes (PVs). Example: Filesystem apiVersion: "local.storage.openshift.io/v1" kind: "LocalVolume" metadata: name: "local-disks" namespace: "openshift-local-storage" 1 spec: nodeSelector: 2 nodeSelectorTerms: - matchExpressions: - key: kubernetes.io/hostname operator: In values: - ip-10-0-140-183 - ip-10-0-158-139 - ip-10-0-164-33 storageClassDevices: - storageClassName: "local-sc" 3 volumeMode: Filesystem 4 fsType: xfs 5 devicePaths: 6 - /path/to/device 7 1 The namespace where the Local Storage Operator is installed. 2 Optional: A node selector containing a list of nodes where the local storage volumes are attached. This example uses the node hostnames, obtained from oc get node . If a value is not defined, then the Local Storage Operator will attempt to find matching disks on all available nodes. 3 The name of the storage class to use when creating persistent volume objects. The Local Storage Operator automatically creates the storage class if it does not exist. Be sure to use a storage class that uniquely identifies this set of local volumes. 4 The volume mode, either Filesystem or Block , that defines the type of local volumes. Note A raw block volume ( volumeMode: Block ) is not formatted with a file system. Use this mode only if any application running on the pod can use raw block devices. 5 The file system that is created when the local volume is mounted for the first time. 6 The path containing a list of local storage devices to choose from. 7 Replace this value with your actual local disks filepath to the LocalVolume resource by-id , such as /dev/disk/by-id/wwn . PVs are created for these local disks when the provisioner is deployed successfully. Note If you are running OpenShift Container Platform on IBM Z with RHEL KVM, you must assign a serial number to your VM disk. Otherwise, the VM disk can not be identified after reboot. You can use the virsh edit <VM> command to add the <serial>mydisk</serial> definition. Example: Block apiVersion: "local.storage.openshift.io/v1" kind: "LocalVolume" metadata: name: "local-disks" namespace: "openshift-local-storage" 1 spec: nodeSelector: 2 nodeSelectorTerms: - matchExpressions: - key: kubernetes.io/hostname operator: In values: - ip-10-0-136-143 - ip-10-0-140-255 - ip-10-0-144-180 storageClassDevices: - storageClassName: "localblock-sc" 3 volumeMode: Block 4 devicePaths: 5 - /path/to/device 6 1 The namespace where the Local Storage Operator is installed. 2 Optional: A node selector containing a list of nodes where the local storage volumes are attached. This example uses the node hostnames, obtained from oc get node . If a value is not defined, then the Local Storage Operator will attempt to find matching disks on all available nodes. 3 The name of the storage class to use when creating persistent volume objects. 4 The volume mode, either Filesystem or Block , that defines the type of local volumes. 5 The path containing a list of local storage devices to choose from. 6 Replace this value with your actual local disks filepath to the LocalVolume resource by-id , such as dev/disk/by-id/wwn . PVs are created for these local disks when the provisioner is deployed successfully. Note If you are running OpenShift Container Platform on IBM Z with RHEL KVM, you must assign a serial number to your VM disk. Otherwise, the VM disk can not be identified after reboot. You can use the virsh edit <VM> command to add the <serial>mydisk</serial> definition. Create the local volume resource in your OpenShift Container Platform cluster. Specify the file you just created: USD oc create -f <local-volume>.yaml Verify that the provisioner was created and that the corresponding daemon sets were created: USD oc get all -n openshift-local-storage Example output NAME READY STATUS RESTARTS AGE pod/diskmaker-manager-9wzms 1/1 Running 0 5m43s pod/diskmaker-manager-jgvjp 1/1 Running 0 5m43s pod/diskmaker-manager-tbdsj 1/1 Running 0 5m43s pod/local-storage-operator-7db4bd9f79-t6k87 1/1 Running 0 14m NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/local-storage-operator-metrics ClusterIP 172.30.135.36 <none> 8383/TCP,8686/TCP 14m NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE daemonset.apps/diskmaker-manager 3 3 3 3 3 <none> 5m43s NAME READY UP-TO-DATE AVAILABLE AGE deployment.apps/local-storage-operator 1/1 1 1 14m NAME DESIRED CURRENT READY AGE replicaset.apps/local-storage-operator-7db4bd9f79 1 1 1 14m Note the desired and current number of daemon set processes. A desired count of 0 indicates that the label selectors were invalid. Verify that the persistent volumes were created: USD oc get pv Example output NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE local-pv-1cec77cf 100Gi RWO Delete Available local-sc 88m local-pv-2ef7cd2a 100Gi RWO Delete Available local-sc 82m local-pv-3fa1c73 100Gi RWO Delete Available local-sc 48m Important Editing the LocalVolume object does not change the fsType or volumeMode of existing persistent volumes because doing so might result in a destructive operation. 4.10.3. Provisioning local volumes without the Local Storage Operator Local volumes cannot be created by dynamic provisioning. Instead, persistent volumes can be created by defining the persistent volume (PV) in an object definition. The local volume provisioner looks for any file system or block volume devices at the paths specified in the defined resource. Important Manual provisioning of PVs includes the risk of potential data leaks across PV reuse when PVCs are deleted. The Local Storage Operator is recommended for automating the life cycle of devices when provisioning local PVs. Prerequisites Local disks are attached to the OpenShift Container Platform nodes. Procedure Define the PV. Create a file, such as example-pv-filesystem.yaml or example-pv-block.yaml , with the PersistentVolume object definition. This resource must define the nodes and paths to the local volumes. Note Do not use different storage class names for the same device. Doing so will create multiple PVs. example-pv-filesystem.yaml apiVersion: v1 kind: PersistentVolume metadata: name: example-pv-filesystem spec: capacity: storage: 100Gi volumeMode: Filesystem 1 accessModes: - ReadWriteOnce persistentVolumeReclaimPolicy: Delete storageClassName: local-storage 2 local: path: /dev/xvdf 3 nodeAffinity: required: nodeSelectorTerms: - matchExpressions: - key: kubernetes.io/hostname operator: In values: - example-node 1 The volume mode, either Filesystem or Block , that defines the type of PVs. 2 The name of the storage class to use when creating PV resources. Use a storage class that uniquely identifies this set of PVs. 3 The path containing a list of local storage devices to choose from, or a directory. You can only specify a directory with Filesystem volumeMode . Note A raw block volume ( volumeMode: block ) is not formatted with a file system. Use this mode only if any application running on the pod can use raw block devices. example-pv-block.yaml apiVersion: v1 kind: PersistentVolume metadata: name: example-pv-block spec: capacity: storage: 100Gi volumeMode: Block 1 accessModes: - ReadWriteOnce persistentVolumeReclaimPolicy: Delete storageClassName: local-storage 2 local: path: /dev/xvdf 3 nodeAffinity: required: nodeSelectorTerms: - matchExpressions: - key: kubernetes.io/hostname operator: In values: - example-node 1 The volume mode, either Filesystem or Block , that defines the type of PVs. 2 The name of the storage class to use when creating PV resources. Be sure to use a storage class that uniquely identifies this set of PVs. 3 The path containing a list of local storage devices to choose from. Create the PV resource in your OpenShift Container Platform cluster. Specify the file you just created: USD oc create -f <example-pv>.yaml Verify that the local PV was created: USD oc get pv Example output NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE example-pv-filesystem 100Gi RWO Delete Available local-storage 3m47s example-pv1 1Gi RWO Delete Bound local-storage/pvc1 local-storage 12h example-pv2 1Gi RWO Delete Bound local-storage/pvc2 local-storage 12h example-pv3 1Gi RWO Delete Bound local-storage/pvc3 local-storage 12h 4.10.4. Creating the local volume persistent volume claim Local volumes must be statically created as a persistent volume claim (PVC) to be accessed by the pod. Prerequisites Persistent volumes have been created using the local volume provisioner. Procedure Create the PVC using the corresponding storage class: kind: PersistentVolumeClaim apiVersion: v1 metadata: name: local-pvc-name 1 spec: accessModes: - ReadWriteOnce volumeMode: Filesystem 2 resources: requests: storage: 100Gi 3 storageClassName: local-sc 4 1 Name of the PVC. 2 The type of the PVC. Defaults to Filesystem . 3 The amount of storage available to the PVC. 4 Name of the storage class required by the claim. Create the PVC in the OpenShift Container Platform cluster, specifying the file you just created: USD oc create -f <local-pvc>.yaml 4.10.5. Attach the local claim After a local volume has been mapped to a persistent volume claim it can be specified inside of a resource. Prerequisites A persistent volume claim exists in the same namespace. Procedure Include the defined claim in the resource spec. The following example declares the persistent volume claim inside a pod: apiVersion: v1 kind: Pod spec: # ... containers: volumeMounts: - name: local-disks 1 mountPath: /data 2 volumes: - name: local-disks persistentVolumeClaim: claimName: local-pvc-name 3 # ... 1 The name of the volume to mount. 2 The path inside the pod where the volume is mounted. Do not mount to the container root, / , or any path that is the same in the host and the container. This can corrupt your host system if the container is sufficiently privileged, such as the host /dev/pts files. It is safe to mount the host by using /host . 3 The name of the existing persistent volume claim to use. Create the resource in the OpenShift Container Platform cluster, specifying the file you just created: USD oc create -f <local-pod>.yaml 4.10.6. Automating discovery and provisioning for local storage devices The Local Storage Operator automates local storage discovery and provisioning. With this feature, you can simplify installation when dynamic provisioning is not available during deployment, such as with bare metal, VMware, or AWS store instances with attached devices. Important Automatic discovery and provisioning is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process. For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope . Important Automatic discovery and provisioning is fully supported when used to deploy Red Hat OpenShift Data Foundation on-premise or with platform-agnostic deployment. Use the following procedure to automatically discover local devices, and to automatically provision local volumes for selected devices. Warning Use the LocalVolumeSet object with caution. When you automatically provision persistent volumes (PVs) from local disks, the local PVs might claim all devices that match. If you are using a LocalVolumeSet object, make sure the Local Storage Operator is the only entity managing local devices on the node. Creating multiple instances of a LocalVolumeSet that target a node more than once is not supported. Prerequisites You have cluster administrator permissions. You have installed the Local Storage Operator. You have attached local disks to OpenShift Container Platform nodes. You have access to the OpenShift Container Platform web console and the oc command-line interface (CLI). Procedure To enable automatic discovery of local devices from the web console: In the Administrator perspective, navigate to Operators Installed Operators and click on the Local Volume Discovery tab. Click Create Local Volume Discovery . Select either All nodes or Select nodes , depending on whether you want to discover available disks on all or specific nodes. Note Only worker nodes are available, regardless of whether you filter using All nodes or Select nodes . Click Create . A local volume discovery instance named auto-discover-devices is displayed. To display a continuous list of available devices on a node: Log in to the OpenShift Container Platform web console. Navigate to Compute Nodes . Click the node name that you want to open. The "Node Details" page is displayed. Select the Disks tab to display the list of the selected devices. The device list updates continuously as local disks are added or removed. You can filter the devices by name, status, type, model, capacity, and mode. To automatically provision local volumes for the discovered devices from the web console: Navigate to Operators Installed Operators and select Local Storage from the list of Operators. Select Local Volume Set Create Local Volume Set . Enter a volume set name and a storage class name. Choose All nodes or Select nodes to apply filters accordingly. Note Only worker nodes are available, regardless of whether you filter using All nodes or Select nodes . Select the disk type, mode, size, and limit you want to apply to the local volume set, and click Create . A message displays after several minutes, indicating that the "Operator reconciled successfully." Alternatively, to provision local volumes for the discovered devices from the CLI: Create an object YAML file to define the local volume set, such as local-volume-set.yaml , as shown in the following example: apiVersion: local.storage.openshift.io/v1alpha1 kind: LocalVolumeSet metadata: name: example-autodetect spec: nodeSelector: nodeSelectorTerms: - matchExpressions: - key: kubernetes.io/hostname operator: In values: - worker-0 - worker-1 storageClassName: example-storageclass 1 volumeMode: Filesystem fsType: ext4 maxDeviceCount: 10 deviceInclusionSpec: deviceTypes: 2 - disk - part deviceMechanicalProperties: - NonRotational minSize: 10G maxSize: 100G models: - SAMSUNG - Crucial_CT525MX3 vendors: - ATA - ST2000LM 1 Determines the storage class that is created for persistent volumes that are provisioned from discovered devices. The Local Storage Operator automatically creates the storage class if it does not exist. Be sure to use a storage class that uniquely identifies this set of local volumes. 2 When using the local volume set feature, the Local Storage Operator does not support the use of logical volume management (LVM) devices. Create the local volume set object: USD oc apply -f local-volume-set.yaml Verify that the local persistent volumes were dynamically provisioned based on the storage class: USD oc get pv Example output NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE local-pv-1cec77cf 100Gi RWO Delete Available example-storageclass 88m local-pv-2ef7cd2a 100Gi RWO Delete Available example-storageclass 82m local-pv-3fa1c73 100Gi RWO Delete Available example-storageclass 48m Note Results are deleted after they are removed from the node. Symlinks must be manually removed. 4.10.7. Using tolerations with Local Storage Operator pods Taints can be applied to nodes to prevent them from running general workloads. To allow the Local Storage Operator to use tainted nodes, you must add tolerations to the Pod or DaemonSet definition. This allows the created resources to run on these tainted nodes. You apply tolerations to the Local Storage Operator pod through the LocalVolume resource and apply taints to a node through the node specification. A taint on a node instructs the node to repel all pods that do not tolerate the taint. Using a specific taint that is not on other pods ensures that the Local Storage Operator pod can also run on that node. Important Taints and tolerations consist of a key, value, and effect. As an argument, it is expressed as key=value:effect . An operator allows you to leave one of these parameters empty. Prerequisites The Local Storage Operator is installed. Local disks are attached to OpenShift Container Platform nodes with a taint. Tainted nodes are expected to provision local storage. Procedure To configure local volumes for scheduling on tainted nodes: Modify the YAML file that defines the Pod and add the LocalVolume spec, as shown in the following example: apiVersion: "local.storage.openshift.io/v1" kind: "LocalVolume" metadata: name: "local-disks" namespace: "openshift-local-storage" spec: tolerations: - key: localstorage 1 operator: Equal 2 value: "localstorage" 3 storageClassDevices: - storageClassName: "localblock-sc" volumeMode: Block 4 devicePaths: 5 - /dev/xvdg 1 Specify the key that you added to the node. 2 Specify the Equal operator to require the key / value parameters to match. If operator is Exists , the system checks that the key exists and ignores the value. If operator is Equal , then the key and value must match. 3 Specify the value local of the tainted node. 4 The volume mode, either Filesystem or Block , defining the type of the local volumes. 5 The path containing a list of local storage devices to choose from. Optional: To create local persistent volumes on only tainted nodes, modify the YAML file and add the LocalVolume spec, as shown in the following example: spec: tolerations: - key: node-role.kubernetes.io/master operator: Exists The defined tolerations will be passed to the resulting daemon sets, allowing the diskmaker and provisioner pods to be created for nodes that contain the specified taints. 4.10.8. Local Storage Operator Metrics OpenShift Container Platform provides the following metrics for the Local Storage Operator: lso_discovery_disk_count : total number of discovered devices on each node lso_lvset_provisioned_PV_count : total number of PVs created by LocalVolumeSet objects lso_lvset_unmatched_disk_count : total number of disks that Local Storage Operator did not select for provisioning because of mismatching criteria lso_lvset_orphaned_symlink_count : number of devices with PVs that no longer match LocalVolumeSet object criteria lso_lv_orphaned_symlink_count : number of devices with PVs that no longer match LocalVolume object criteria lso_lv_provisioned_PV_count : total number of provisioned PVs for LocalVolume To use these metrics, be sure to: Enable support for monitoring when installing the Local Storage Operator. When upgrading to OpenShift Container Platform 4.9 or later, enable metric support manually by adding the operator-metering=true label to the namespace. For more information about metrics, see Managing metrics . 4.10.9. Deleting the Local Storage Operator resources 4.10.9.1. Removing a local volume or local volume set Occasionally, local volumes and local volume sets must be deleted. While removing the entry in the resource and deleting the persistent volume is typically enough, if you want to reuse the same device path or have it managed by a different storage class, then additional steps are needed. Note The following procedure outlines an example for removing a local volume. The same procedure can also be used to remove symlinks for a local volume set custom resource. Prerequisites The persistent volume must be in a Released or Available state. Warning Deleting a persistent volume that is still in use can result in data loss or corruption. Procedure Edit the previously created local volume to remove any unwanted disks. Edit the cluster resource: USD oc edit localvolume <name> -n openshift-local-storage Navigate to the lines under devicePaths , and delete any representing unwanted disks. Delete any persistent volumes created. USD oc delete pv <pv-name> Delete directory and included symlinks on the node. Warning The following step involves accessing a node as the root user. Modifying the state of the node beyond the steps in this procedure could result in cluster instability. USD oc debug node/<node-name> -- chroot /host rm -rf /mnt/local-storage/<sc-name> 1 1 The name of the storage class used to create the local volumes. 4.10.9.2. Uninstalling the Local Storage Operator To uninstall the Local Storage Operator, you must remove the Operator and all created resources in the openshift-local-storage project. Warning Uninstalling the Local Storage Operator while local storage PVs are still in use is not recommended. While the PVs will remain after the Operator's removal, there might be indeterminate behavior if the Operator is uninstalled and reinstalled without removing the PVs and local storage resources. Prerequisites Access to the OpenShift Container Platform web console. Procedure Delete any local volume resources installed in the project, such as localvolume , localvolumeset , and localvolumediscovery : USD oc delete localvolume --all --all-namespaces USD oc delete localvolumeset --all --all-namespaces USD oc delete localvolumediscovery --all --all-namespaces Uninstall the Local Storage Operator from the web console. Log in to the OpenShift Container Platform web console. Navigate to Operators Installed Operators . Type Local Storage into the filter box to locate the Local Storage Operator. Click the Options menu at the end of the Local Storage Operator. Click Uninstall Operator . Click Remove in the window that appears. The PVs created by the Local Storage Operator will remain in the cluster until deleted. After these volumes are no longer in use, delete them by running the following command: USD oc delete pv <pv-name> Delete the openshift-local-storage project: USD oc delete project openshift-local-storage 4.11. Persistent storage using NFS OpenShift Container Platform clusters can be provisioned with persistent storage using NFS. Persistent volumes (PVs) and persistent volume claims (PVCs) provide a convenient method for sharing a volume across a project. While the NFS-specific information contained in a PV definition could also be defined directly in a Pod definition, doing so does not create the volume as a distinct cluster resource, making the volume more susceptible to conflicts. Additional resources Mounting NFS shares 4.11.1. Provisioning Storage must exist in the underlying infrastructure before it can be mounted as a volume in OpenShift Container Platform. To provision NFS volumes, a list of NFS servers and export paths are all that is required. Procedure Create an object definition for the PV: apiVersion: v1 kind: PersistentVolume metadata: name: pv0001 1 spec: capacity: storage: 5Gi 2 accessModes: - ReadWriteOnce 3 nfs: 4 path: /tmp 5 server: 172.17.0.2 6 persistentVolumeReclaimPolicy: Retain 7 1 The name of the volume. This is the PV identity in various oc <command> pod commands. 2 The amount of storage allocated to this volume. 3 Though this appears to be related to controlling access to the volume, it is actually used similarly to labels and used to match a PVC to a PV. Currently, no access rules are enforced based on the accessModes . 4 The volume type being used, in this case the nfs plugin. 5 The path that is exported by the NFS server. 6 The hostname or IP address of the NFS server. 7 The reclaim policy for the PV. This defines what happens to a volume when released. Note Each NFS volume must be mountable by all schedulable nodes in the cluster. Verify that the PV was created: USD oc get pv Example output NAME LABELS CAPACITY ACCESSMODES STATUS CLAIM REASON AGE pv0001 <none> 5Gi RWO Available 31s Create a persistent volume claim that binds to the new PV: apiVersion: v1 kind: PersistentVolumeClaim metadata: name: nfs-claim1 spec: accessModes: - ReadWriteOnce 1 resources: requests: storage: 5Gi 2 volumeName: pv0001 storageClassName: "" 1 The access modes do not enforce security, but rather act as labels to match a PV to a PVC. 2 This claim looks for PVs offering 5Gi or greater capacity. Verify that the persistent volume claim was created: USD oc get pvc Example output NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE nfs-claim1 Bound pv0001 5Gi RWO 2m 4.11.2. Enforcing disk quotas You can use disk partitions to enforce disk quotas and size constraints. Each partition can be its own export. Each export is one PV. OpenShift Container Platform enforces unique names for PVs, but the uniqueness of the NFS volume's server and path is up to the administrator. Enforcing quotas in this way allows the developer to request persistent storage by a specific amount, such as 10Gi, and be matched with a corresponding volume of equal or greater capacity. 4.11.3. NFS volume security This section covers NFS volume security, including matching permissions and SELinux considerations. The user is expected to understand the basics of POSIX permissions, process UIDs, supplemental groups, and SELinux. Developers request NFS storage by referencing either a PVC by name or the NFS volume plugin directly in the volumes section of their Pod definition. The /etc/exports file on the NFS server contains the accessible NFS directories. The target NFS directory has POSIX owner and group IDs. The OpenShift Container Platform NFS plugin mounts the container's NFS directory with the same POSIX ownership and permissions found on the exported NFS directory. However, the container is not run with its effective UID equal to the owner of the NFS mount, which is the desired behavior. As an example, if the target NFS directory appears on the NFS server as: USD ls -lZ /opt/nfs -d Example output drwxrws---. nfsnobody 5555 unconfined_u:object_r:usr_t:s0 /opt/nfs USD id nfsnobody Example output uid=65534(nfsnobody) gid=65534(nfsnobody) groups=65534(nfsnobody) Then the container must match SELinux labels, and either run with a UID of 65534 , the nfsnobody owner, or with 5555 in its supplemental groups to access the directory. Note The owner ID of 65534 is used as an example. Even though NFS's root_squash maps root , uid 0 , to nfsnobody , uid 65534 , NFS exports can have arbitrary owner IDs. Owner 65534 is not required for NFS exports. 4.11.3.1. Group IDs The recommended way to handle NFS access, assuming it is not an option to change permissions on the NFS export, is to use supplemental groups. Supplemental groups in OpenShift Container Platform are used for shared storage, of which NFS is an example. In contrast, block storage such as iSCSI uses the fsGroup SCC strategy and the fsGroup value in the securityContext of the pod. Note To gain access to persistent storage, it is generally preferable to use supplemental group IDs versus user IDs. Because the group ID on the example target NFS directory is 5555 , the pod can define that group ID using supplementalGroups under the securityContext definition of the pod. For example: spec: containers: - name: ... securityContext: 1 supplementalGroups: [5555] 2 1 securityContext must be defined at the pod level, not under a specific container. 2 An array of GIDs defined for the pod. In this case, there is one element in the array. Additional GIDs would be comma-separated. Assuming there are no custom SCCs that might satisfy the pod requirements, the pod likely matches the restricted SCC. This SCC has the supplementalGroups strategy set to RunAsAny , meaning that any supplied group ID is accepted without range checking. As a result, the above pod passes admissions and is launched. However, if group ID range checking is desired, a custom SCC is the preferred solution. A custom SCC can be created such that minimum and maximum group IDs are defined, group ID range checking is enforced, and a group ID of 5555 is allowed. Note To use a custom SCC, you must first add it to the appropriate service account. For example, use the default service account in the given project unless another has been specified on the Pod specification. 4.11.3.2. User IDs User IDs can be defined in the container image or in the Pod definition. Note It is generally preferable to use supplemental group IDs to gain access to persistent storage versus using user IDs. In the example target NFS directory shown above, the container needs its UID set to 65534 , ignoring group IDs for the moment, so the following can be added to the Pod definition: spec: containers: 1 - name: ... securityContext: runAsUser: 65534 2 1 Pods contain a securityContext definition specific to each container and a pod's securityContext which applies to all containers defined in the pod. 2 65534 is the nfsnobody user. Assuming that the project is default and the SCC is restricted , the user ID of 65534 as requested by the pod is not allowed. Therefore, the pod fails for the following reasons: It requests 65534 as its user ID. All SCCs available to the pod are examined to see which SCC allows a user ID of 65534 . While all policies of the SCCs are checked, the focus here is on user ID. Because all available SCCs use MustRunAsRange for their runAsUser strategy, UID range checking is required. 65534 is not included in the SCC or project's user ID range. It is generally considered a good practice not to modify the predefined SCCs. The preferred way to fix this situation is to create a custom SCC A custom SCC can be created such that minimum and maximum user IDs are defined, UID range checking is still enforced, and the UID of 65534 is allowed. Note To use a custom SCC, you must first add it to the appropriate service account. For example, use the default service account in the given project unless another has been specified on the Pod specification. 4.11.3.3. SELinux Red Hat Enterprise Linux (RHEL) and Red Hat Enterprise Linux CoreOS (RHCOS) systems are configured to use SELinux on remote NFS servers by default. For non-RHEL and non-RHCOS systems, SELinux does not allow writing from a pod to a remote NFS server. The NFS volume mounts correctly but it is read-only. You will need to enable the correct SELinux permissions by using the following procedure. Prerequisites The container-selinux package must be installed. This package provides the virt_use_nfs SELinux boolean. Procedure Enable the virt_use_nfs boolean using the following command. The -P option makes this boolean persistent across reboots. # setsebool -P virt_use_nfs 1 4.11.3.4. Export settings To enable arbitrary container users to read and write the volume, each exported volume on the NFS server should conform to the following conditions: Every export must be exported using the following format: /<example_fs> *(rw,root_squash) The firewall must be configured to allow traffic to the mount point. For NFSv4, configure the default port 2049 ( nfs ). NFSv4 # iptables -I INPUT 1 -p tcp --dport 2049 -j ACCEPT For NFSv3, there are three ports to configure: 2049 ( nfs ), 20048 ( mountd ), and 111 ( portmapper ). NFSv3 # iptables -I INPUT 1 -p tcp --dport 2049 -j ACCEPT # iptables -I INPUT 1 -p tcp --dport 20048 -j ACCEPT # iptables -I INPUT 1 -p tcp --dport 111 -j ACCEPT The NFS export and directory must be set up so that they are accessible by the target pods. Either set the export to be owned by the container's primary UID, or supply the pod group access using supplementalGroups , as shown in the group IDs above. 4.11.4. Reclaiming resources NFS implements the OpenShift Container Platform Recyclable plugin interface. Automatic processes handle reclamation tasks based on policies set on each persistent volume. By default, PVs are set to Retain . Once claim to a PVC is deleted, and the PV is released, the PV object should not be reused. Instead, a new PV should be created with the same basic volume details as the original. For example, the administrator creates a PV named nfs1 : apiVersion: v1 kind: PersistentVolume metadata: name: nfs1 spec: capacity: storage: 1Mi accessModes: - ReadWriteMany nfs: server: 192.168.1.1 path: "/" The user creates PVC1 , which binds to nfs1 . The user then deletes PVC1 , releasing claim to nfs1 . This results in nfs1 being Released . If the administrator wants to make the same NFS share available, they should create a new PV with the same NFS server details, but a different PV name: apiVersion: v1 kind: PersistentVolume metadata: name: nfs2 spec: capacity: storage: 1Mi accessModes: - ReadWriteMany nfs: server: 192.168.1.1 path: "/" Deleting the original PV and re-creating it with the same name is discouraged. Attempting to manually change the status of a PV from Released to Available causes errors and potential data loss. 4.11.5. Additional configuration and troubleshooting Depending on what version of NFS is being used and how it is configured, there may be additional configuration steps needed for proper export and security mapping. The following are some that may apply: NFSv4 mount incorrectly shows all files with ownership of nobody:nobody Could be attributed to the ID mapping settings, found in /etc/idmapd.conf on your NFS. See this Red Hat Solution . Disabling ID mapping on NFSv4 On both the NFS client and server, run: # echo 'Y' > /sys/module/nfsd/parameters/nfs4_disable_idmapping 4.12. Red Hat OpenShift Data Foundation Red Hat OpenShift Data Foundation is a provider of agnostic persistent storage for OpenShift Container Platform supporting file, block, and object storage, either in-house or in hybrid clouds. As a Red Hat storage solution, Red Hat OpenShift Data Foundation is completely integrated with OpenShift Container Platform for deployment, management, and monitoring. Red Hat OpenShift Data Foundation provides its own documentation library. The complete set of Red Hat OpenShift Data Foundation documentation is available at https://access.redhat.com/documentation/en-us/red_hat_openshift_data_foundation . Important OpenShift Data Foundation on top of Red Hat Hyperconverged Infrastructure (RHHI) for Virtualization, which uses hyperconverged nodes that host virtual machines installed with OpenShift Container Platform, is not a supported configuration. For more information about supported platforms, see the Red Hat OpenShift Data Foundation Supportability and Interoperability Guide . 4.13. Persistent storage using VMware vSphere volumes OpenShift Container Platform allows use of VMware vSphere's Virtual Machine Disk (VMDK) volumes. You can provision your OpenShift Container Platform cluster with persistent storage using VMware vSphere. Some familiarity with Kubernetes and VMware vSphere is assumed. VMware vSphere volumes can be provisioned dynamically. OpenShift Container Platform creates the disk in vSphere and attaches this disk to the correct image. Note OpenShift Container Platform provisions new volumes as independent persistent disks that can freely attach and detach the volume on any node in the cluster. Consequently, you cannot back up volumes that use snapshots, or restore volumes from snapshots. See Snapshot Limitations for more information. The Kubernetes persistent volume framework allows administrators to provision a cluster with persistent storage and gives users a way to request those resources without having any knowledge of the underlying infrastructure. Persistent volumes are not bound to a single project or namespace; they can be shared across the OpenShift Container Platform cluster. Persistent volume claims are specific to a project or namespace and can be requested by users. Important OpenShift Container Platform defaults to using an in-tree (non-CSI) plugin to provision vSphere storage. In future OpenShift Container Platform versions, volumes provisioned using existing in-tree plugins are planned for migration to their equivalent CSI driver. CSI automatic migration should be seamless. Migration does not change how you use all existing API objects, such as persistent volumes, persistent volume claims, and storage classes. For more information about migration, see CSI automatic migration . After full migration, in-tree plugins will eventually be removed in future versions of OpenShift Container Platform. Additional resources VMware vSphere 4.13.1. Dynamically provisioning VMware vSphere volumes Dynamically provisioning VMware vSphere volumes is the recommended method. 4.13.2. Prerequisites An OpenShift Container Platform cluster installed on a VMware vSphere version that meets the requirements for the components that you use. See Installing a cluster on vSphere for information about vSphere version support. You can use either of the following procedures to dynamically provision these volumes using the default storage class. 4.13.2.1. Dynamically provisioning VMware vSphere volumes using the UI OpenShift Container Platform installs a default storage class, named thin , that uses the thin disk format for provisioning volumes. Prerequisites Storage must exist in the underlying infrastructure before it can be mounted as a volume in OpenShift Container Platform. Procedure In the OpenShift Container Platform console, click Storage Persistent Volume Claims . In the persistent volume claims overview, click Create Persistent Volume Claim . Define the required options on the resulting page. Select the thin storage class. Enter a unique name for the storage claim. Select the access mode to determine the read and write access for the created storage claim. Define the size of the storage claim. Click Create to create the persistent volume claim and generate a persistent volume. 4.13.2.2. Dynamically provisioning VMware vSphere volumes using the CLI OpenShift Container Platform installs a default StorageClass, named thin , that uses the thin disk format for provisioning volumes. Prerequisites Storage must exist in the underlying infrastructure before it can be mounted as a volume in OpenShift Container Platform. Procedure (CLI) You can define a VMware vSphere PersistentVolumeClaim by creating a file, pvc.yaml , with the following contents: kind: PersistentVolumeClaim apiVersion: v1 metadata: name: pvc 1 spec: accessModes: - ReadWriteOnce 2 resources: requests: storage: 1Gi 3 1 A unique name that represents the persistent volume claim. 2 The access mode of the persistent volume claim. With ReadWriteOnce , the volume can be mounted with read and write permissions by a single node. 3 The size of the persistent volume claim. Enter the following command to create the PersistentVolumeClaim object from the file: USD oc create -f pvc.yaml 4.13.3. Statically provisioning VMware vSphere volumes To statically provision VMware vSphere volumes you must create the virtual machine disks for reference by the persistent volume framework. Prerequisites Storage must exist in the underlying infrastructure before it can be mounted as a volume in OpenShift Container Platform. Procedure Create the virtual machine disks. Virtual machine disks (VMDKs) must be created manually before statically provisioning VMware vSphere volumes. Use either of the following methods: Create using vmkfstools . Access ESX through Secure Shell (SSH) and then use following command to create a VMDK volume: USD vmkfstools -c <size> /vmfs/volumes/<datastore-name>/volumes/<disk-name>.vmdk Create using vmware-diskmanager : USD shell vmware-vdiskmanager -c -t 0 -s <size> -a lsilogic <disk-name>.vmdk Create a persistent volume that references the VMDKs. Create a file, pv1.yaml , with the PersistentVolume object definition: apiVersion: v1 kind: PersistentVolume metadata: name: pv1 1 spec: capacity: storage: 1Gi 2 accessModes: - ReadWriteOnce persistentVolumeReclaimPolicy: Retain vsphereVolume: 3 volumePath: "[datastore1] volumes/myDisk" 4 fsType: ext4 5 1 The name of the volume. This name is how it is identified by persistent volume claims or pods. 2 The amount of storage allocated to this volume. 3 The volume type used, with vsphereVolume for vSphere volumes. The label is used to mount a vSphere VMDK volume into pods. The contents of a volume are preserved when it is unmounted. The volume type supports VMFS and VSAN datastore. 4 The existing VMDK volume to use. If you used vmkfstools , you must enclose the datastore name in square brackets, [] , in the volume definition, as shown previously. 5 The file system type to mount. For example, ext4, xfs, or other file systems. Important Changing the value of the fsType parameter after the volume is formatted and provisioned can result in data loss and pod failure. Create the PersistentVolume object from the file: USD oc create -f pv1.yaml Create a persistent volume claim that maps to the persistent volume you created in the step. Create a file, pvc1.yaml , with the PersistentVolumeClaim object definition: apiVersion: v1 kind: PersistentVolumeClaim metadata: name: pvc1 1 spec: accessModes: - ReadWriteOnce 2 resources: requests: storage: "1Gi" 3 volumeName: pv1 4 1 A unique name that represents the persistent volume claim. 2 The access mode of the persistent volume claim. With ReadWriteOnce, the volume can be mounted with read and write permissions by a single node. 3 The size of the persistent volume claim. 4 The name of the existing persistent volume. Create the PersistentVolumeClaim object from the file: USD oc create -f pvc1.yaml 4.13.3.1. Formatting VMware vSphere volumes Before OpenShift Container Platform mounts the volume and passes it to a container, it checks that the volume contains a file system that is specified by the fsType parameter value in the PersistentVolume (PV) definition. If the device is not formatted with the file system, all data from the device is erased, and the device is automatically formatted with the specified file system. Because OpenShift Container Platform formats them before the first use, you can use unformatted vSphere volumes as PVs.

Commands:
cat << EOF | oc create -f - apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: <storage-class-name> 1 parameters: fsType: ext4 2 encrypted: "true" kmsKeyId: keyvalue 3 provisioner: ebs.csi.aws.com reclaimPolicy: Delete volumeBindingMode: WaitForFirstConsumer EOF
cat << EOF | oc create -f - apiVersion: v1 kind: PersistentVolumeClaim metadata: name: mypvc spec: accessModes: - ReadWriteOnce volumeMode: Filesystem storageClassName: <storage-class-name> resources: requests: storage: 1Gi EOF
cat << EOF | oc create -f - kind: Pod metadata: name: mypod spec: containers: - name: httpd image: quay.io/centos7/httpd-24-centos7 ports: - containerPort: 80 volumeMounts: - mountPath: /mnt/storage name: data volumes: - name: data persistentVolumeClaim: claimName: mypvc EOF
oc edit machineset <machine-set-name>
apiVersion: machine.openshift.io/v1beta1 kind: MachineSet spec: template: spec: metadata: labels: disk: ultrassd 1 providerSpec: value: ultraSSDCapability: Enabled 2
oc create -f <machine-set-name>.yaml
apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: ultra-disk-sc 1 parameters: cachingMode: None diskIopsReadWrite: "2000" 2 diskMbpsReadWrite: "320" 3 kind: managed skuname: UltraSSD_LRS provisioner: disk.csi.azure.com 4 reclaimPolicy: Delete volumeBindingMode: WaitForFirstConsumer 5
apiVersion: v1 kind: PersistentVolumeClaim metadata: name: ultra-disk 1 spec: accessModes: - ReadWriteOnce storageClassName: ultra-disk-sc 2 resources: requests: storage: 4Gi 3
apiVersion: v1 kind: Pod metadata: name: nginx-ultra spec: nodeSelector: disk: ultrassd 1 containers: - name: nginx-ultra image: alpine:latest command: - "sleep" - "infinity" volumeMounts: - mountPath: "/mnt/azure" name: volume volumes: - name: volume persistentVolumeClaim: claimName: ultra-disk 2
oc get machines
oc debug node/<node-name> -- chroot /host lsblk
apiVersion: v1 kind: Pod metadata: name: ssd-benchmark1 spec: containers: - name: ssd-benchmark1 image: nginx ports: - containerPort: 80 name: "http-server" volumeMounts: - name: lun0p1 mountPath: "/tmp" volumes: - name: lun0p1 hostPath: path: /var/lib/lun0p1 type: DirectoryOrCreate nodeSelector: disktype: ultrassd
StorageAccountType UltraSSD_LRS can be used only when additionalCapabilities.ultraSSDEnabled is set.
oc -n <stuck_pod_namespace> describe pod <stuck_pod_name>
oc create secret generic <secret-name> --from-literal=azurestorageaccountname=<storage-account> \ 1 --from-literal=azurestorageaccountkey=<storage-account-key> 2
apiVersion: "v1" kind: "PersistentVolume" metadata: name: "pv0001" 1 spec: capacity: storage: "5Gi" 2 accessModes: - "ReadWriteOnce" storageClassName: azure-file-sc azureFile: secretName: <secret-name> 3 shareName: share-1 4 readOnly: false
apiVersion: "v1" kind: "PersistentVolumeClaim" metadata: name: "claim1" 1 spec: accessModes: - "ReadWriteOnce" resources: requests: storage: "5Gi" 2 storageClassName: azure-file-sc 3 volumeName: "pv0001" 4
apiVersion: v1 kind: Pod metadata: name: pod-name 1 spec: containers: volumeMounts: - mountPath: "/data" 2 name: azure-file-share volumes: - name: azure-file-share persistentVolumeClaim: claimName: claim1 3
apiVersion: "v1" kind: "PersistentVolume" metadata: name: "pv0001" 1 spec: capacity: storage: "5Gi" 2 accessModes: - "ReadWriteOnce" cinder: 3 fsType: "ext3" 4 volumeID: "f37a03aa-6212-4c62-a805-9ce139fab180" 5
oc create -f cinder-persistentvolume.yaml
oc create serviceaccount <service_account>
oc adm policy add-scc-to-user <new_scc> -z <service_account> -n <project>
apiVersion: v1 kind: ReplicationController metadata: name: frontend-1 spec: replicas: 1 1 selector: 2 name: frontend template: 3 metadata: labels: 4 name: frontend 5 spec: containers: - image: openshift/hello-openshift name: helloworld ports: - containerPort: 8080 protocol: TCP restartPolicy: Always serviceAccountName: <service_account> 6 securityContext: fsGroup: 7777 7
apiVersion: v1 kind: PersistentVolume metadata: name: pv0001 spec: capacity: storage: 1Gi accessModes: - ReadWriteOnce fc: wwids: [scsi-3600508b400105e210000900000490000] 1 targetWWNs: ['500a0981891b8dc5', '500a0981991b8dc5'] 2 lun: 2 3 fsType: ext4
{ "fooServer": "192.168.0.1:1234", 1 "fooVolumeName": "bar", "kubernetes.io/fsType": "ext4", 2 "kubernetes.io/readwrite": "ro", 3 "kubernetes.io/secret/<key name>": "<key value>", 4 "kubernetes.io/secret/<another key name>": "<another key value>", }
status: <Success/Failure/Not supported>
message: <Reason for success/failure>
apiVersion: v1 kind: PersistentVolume metadata: name: pv0001 1 spec: capacity: storage: 1Gi 2 accessModes: - ReadWriteOnce flexVolume: driver: openshift.com/foo 3 fsType: "ext4" 4 secretRef: foo-secret 5 readOnly: true 6 options: 7 fooServer: 192.168.0.1:1234 fooVolumeName: bar
"fsType":"<FS type>", "readwrite":"<rw>", "secret/key1":"<secret1>" "secret/keyN":"<secretN>"
apiVersion: v1 kind: Pod metadata: name: test-host-mount spec: containers: - image: registry.access.redhat.com/ubi8/ubi name: test-container command: ['sh', '-c', 'sleep 3600'] volumeMounts: - mountPath: /host name: host-slash volumes: - name: host-slash hostPath: path: / type: ''
apiVersion: v1 kind: PersistentVolume metadata: name: task-pv-volume 1 labels: type: local spec: storageClassName: manual 2 capacity: storage: 5Gi accessModes: - ReadWriteOnce 3 persistentVolumeReclaimPolicy: Retain hostPath: path: "/mnt/data" 4
oc create -f pv.yaml
apiVersion: v1 kind: PersistentVolumeClaim metadata: name: task-pvc-volume spec: accessModes: - ReadWriteOnce resources: requests: storage: 1Gi storageClassName: manual
oc create -f pvc.yaml
apiVersion: v1 kind: Pod metadata: name: pod-name 1 spec: containers: securityContext: privileged: true 2 volumeMounts: - mountPath: /data 3 name: hostpath-privileged securityContext: {} volumes: - name: hostpath-privileged persistentVolumeClaim: claimName: task-pvc-volume 4
apiVersion: v1 kind: PersistentVolume metadata: name: iscsi-pv spec: capacity: storage: 1Gi accessModes: - ReadWriteOnce iscsi: targetPortal: 10.16.154.81:3260 iqn: iqn.2014-12.example.server:storage.target00 lun: 0 fsType: 'ext4'
apiVersion: v1 kind: PersistentVolume metadata: name: iscsi-pv spec: capacity: storage: 1Gi accessModes: - ReadWriteOnce iscsi: targetPortal: 10.0.0.1:3260 iqn: iqn.2016-04.test.com:storage.target00 lun: 0 fsType: ext4 chapAuthDiscovery: true 1 chapAuthSession: true 2 secretRef: name: chap-secret 3
apiVersion: v1 kind: PersistentVolume metadata: name: iscsi-pv spec: capacity: storage: 1Gi accessModes: - ReadWriteOnce iscsi: targetPortal: 10.0.0.1:3260 portals: ['10.0.2.16:3260', '10.0.2.17:3260', '10.0.2.18:3260'] 1 iqn: iqn.2016-04.test.com:storage.target00 lun: 0 fsType: ext4 readOnly: false
apiVersion: v1 kind: PersistentVolume metadata: name: iscsi-pv spec: capacity: storage: 1Gi accessModes: - ReadWriteOnce iscsi: targetPortal: 10.0.0.1:3260 portals: ['10.0.2.16:3260', '10.0.2.17:3260', '10.0.2.18:3260'] iqn: iqn.2016-04.test.com:storage.target00 lun: 0 initiatorName: iqn.2016-04.test.com:custom.iqn 1 fsType: ext4 readOnly: false
oc adm new-project openshift-local-storage
oc annotate namespace openshift-local-storage openshift.io/node-selector=''
oc annotate namespace openshift-local-storage workload.openshift.io/allowed='management'
apiVersion: operators.coreos.com/v1 kind: OperatorGroup metadata: name: local-operator-group namespace: openshift-local-storage spec: targetNamespaces: - openshift-local-storage --- apiVersion: operators.coreos.com/v1alpha1 kind: Subscription metadata: name: local-storage-operator namespace: openshift-local-storage spec: channel: stable installPlanApproval: Automatic 1 name: local-storage-operator source: redhat-operators sourceNamespace: openshift-marketplace
oc apply -f openshift-local-storage.yaml
oc -n openshift-local-storage get pods
NAME READY STATUS RESTARTS AGE local-storage-operator-746bf599c9-vlt5t 1/1 Running 0 19m
oc get csvs -n openshift-local-storage
NAME DISPLAY VERSION REPLACES PHASE local-storage-operator.4.2.26-202003230335 Local Storage 4.2.26-202003230335 Succeeded
apiVersion: "local.storage.openshift.io/v1" kind: "LocalVolume" metadata: name: "local-disks" namespace: "openshift-local-storage" 1 spec: nodeSelector: 2 nodeSelectorTerms: - matchExpressions: - key: kubernetes.io/hostname operator: In values: - ip-10-0-140-183 - ip-10-0-158-139 - ip-10-0-164-33 storageClassDevices: - storageClassName: "local-sc" 3 volumeMode: Filesystem 4 fsType: xfs 5 devicePaths: 6 - /path/to/device 7
apiVersion: "local.storage.openshift.io/v1" kind: "LocalVolume" metadata: name: "local-disks" namespace: "openshift-local-storage" 1 spec: nodeSelector: 2 nodeSelectorTerms: - matchExpressions: - key: kubernetes.io/hostname operator: In values: - ip-10-0-136-143 - ip-10-0-140-255 - ip-10-0-144-180 storageClassDevices: - storageClassName: "localblock-sc" 3 volumeMode: Block 4 devicePaths: 5 - /path/to/device 6
oc create -f <local-volume>.yaml
oc get all -n openshift-local-storage
NAME READY STATUS RESTARTS AGE pod/diskmaker-manager-9wzms 1/1 Running 0 5m43s pod/diskmaker-manager-jgvjp 1/1 Running 0 5m43s pod/diskmaker-manager-tbdsj 1/1 Running 0 5m43s pod/local-storage-operator-7db4bd9f79-t6k87 1/1 Running 0 14m NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/local-storage-operator-metrics ClusterIP 172.30.135.36 <none> 8383/TCP,8686/TCP 14m NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE daemonset.apps/diskmaker-manager 3 3 3 3 3 <none> 5m43s NAME READY UP-TO-DATE AVAILABLE AGE deployment.apps/local-storage-operator 1/1 1 1 14m NAME DESIRED CURRENT READY AGE replicaset.apps/local-storage-operator-7db4bd9f79 1 1 1 14m
oc get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE local-pv-1cec77cf 100Gi RWO Delete Available local-sc 88m local-pv-2ef7cd2a 100Gi RWO Delete Available local-sc 82m local-pv-3fa1c73 100Gi RWO Delete Available local-sc 48m
apiVersion: v1 kind: PersistentVolume metadata: name: example-pv-filesystem spec: capacity: storage: 100Gi volumeMode: Filesystem 1 accessModes: - ReadWriteOnce persistentVolumeReclaimPolicy: Delete storageClassName: local-storage 2 local: path: /dev/xvdf 3 nodeAffinity: required: nodeSelectorTerms: - matchExpressions: - key: kubernetes.io/hostname operator: In values: - example-node
apiVersion: v1 kind: PersistentVolume metadata: name: example-pv-block spec: capacity: storage: 100Gi volumeMode: Block 1 accessModes: - ReadWriteOnce persistentVolumeReclaimPolicy: Delete storageClassName: local-storage 2 local: path: /dev/xvdf 3 nodeAffinity: required: nodeSelectorTerms: - matchExpressions: - key: kubernetes.io/hostname operator: In values: - example-node
oc create -f <example-pv>.yaml
oc get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE example-pv-filesystem 100Gi RWO Delete Available local-storage 3m47s example-pv1 1Gi RWO Delete Bound local-storage/pvc1 local-storage 12h example-pv2 1Gi RWO Delete Bound local-storage/pvc2 local-storage 12h example-pv3 1Gi RWO Delete Bound local-storage/pvc3 local-storage 12h
kind: PersistentVolumeClaim apiVersion: v1 metadata: name: local-pvc-name 1 spec: accessModes: - ReadWriteOnce volumeMode: Filesystem 2 resources: requests: storage: 100Gi 3 storageClassName: local-sc 4
oc create -f <local-pvc>.yaml
apiVersion: v1 kind: Pod spec: containers: volumeMounts: - name: local-disks 1 mountPath: /data 2 volumes: - name: local-disks persistentVolumeClaim: claimName: local-pvc-name 3
oc create -f <local-pod>.yaml
apiVersion: local.storage.openshift.io/v1alpha1 kind: LocalVolumeSet metadata: name: example-autodetect spec: nodeSelector: nodeSelectorTerms: - matchExpressions: - key: kubernetes.io/hostname operator: In values: - worker-0 - worker-1 storageClassName: example-storageclass 1 volumeMode: Filesystem fsType: ext4 maxDeviceCount: 10 deviceInclusionSpec: deviceTypes: 2 - disk - part deviceMechanicalProperties: - NonRotational minSize: 10G maxSize: 100G models: - SAMSUNG - Crucial_CT525MX3 vendors: - ATA - ST2000LM
oc apply -f local-volume-set.yaml
oc get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE local-pv-1cec77cf 100Gi RWO Delete Available example-storageclass 88m local-pv-2ef7cd2a 100Gi RWO Delete Available example-storageclass 82m local-pv-3fa1c73 100Gi RWO Delete Available example-storageclass 48m
apiVersion: "local.storage.openshift.io/v1" kind: "LocalVolume" metadata: name: "local-disks" namespace: "openshift-local-storage" spec: tolerations: - key: localstorage 1 operator: Equal 2 value: "localstorage" 3 storageClassDevices: - storageClassName: "localblock-sc" volumeMode: Block 4 devicePaths: 5 - /dev/xvdg
spec: tolerations: - key: node-role.kubernetes.io/master operator: Exists
oc edit localvolume <name> -n openshift-local-storage
oc delete pv <pv-name>
oc debug node/<node-name> -- chroot /host rm -rf /mnt/local-storage/<sc-name> 1
oc delete localvolume --all --all-namespaces oc delete localvolumeset --all --all-namespaces oc delete localvolumediscovery --all --all-namespaces
oc delete pv <pv-name>
oc delete project openshift-local-storage
apiVersion: v1 kind: PersistentVolume metadata: name: pv0001 1 spec: capacity: storage: 5Gi 2 accessModes: - ReadWriteOnce 3 nfs: 4 path: /tmp 5 server: 172.17.0.2 6 persistentVolumeReclaimPolicy: Retain 7
oc get pv
NAME LABELS CAPACITY ACCESSMODES STATUS CLAIM REASON AGE pv0001 <none> 5Gi RWO Available 31s
apiVersion: v1 kind: PersistentVolumeClaim metadata: name: nfs-claim1 spec: accessModes: - ReadWriteOnce 1 resources: requests: storage: 5Gi 2 volumeName: pv0001 storageClassName: ""
oc get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE nfs-claim1 Bound pv0001 5Gi RWO 2m
ls -lZ /opt/nfs -d
drwxrws---. nfsnobody 5555 unconfined_u:object_r:usr_t:s0 /opt/nfs
id nfsnobody
uid=65534(nfsnobody) gid=65534(nfsnobody) groups=65534(nfsnobody)
spec: containers: - name: securityContext: 1 supplementalGroups: [5555] 2
spec: containers: 1 - name: securityContext: runAsUser: 65534 2
setsebool -P virt_use_nfs 1
/<example_fs> *(rw,root_squash)
iptables -I INPUT 1 -p tcp --dport 2049 -j ACCEPT
iptables -I INPUT 1 -p tcp --dport 2049 -j ACCEPT
iptables -I INPUT 1 -p tcp --dport 20048 -j ACCEPT
iptables -I INPUT 1 -p tcp --dport 111 -j ACCEPT
apiVersion: v1 kind: PersistentVolume metadata: name: nfs1 spec: capacity: storage: 1Mi accessModes: - ReadWriteMany nfs: server: 192.168.1.1 path: "/"
apiVersion: v1 kind: PersistentVolume metadata: name: nfs2 spec: capacity: storage: 1Mi accessModes: - ReadWriteMany nfs: server: 192.168.1.1 path: "/"
echo 'Y' > /sys/module/nfsd/parameters/nfs4_disable_idmapping
kind: PersistentVolumeClaim apiVersion: v1 metadata: name: pvc 1 spec: accessModes: - ReadWriteOnce 2 resources: requests: storage: 1Gi 3
oc create -f pvc.yaml
vmkfstools -c <size> /vmfs/volumes/<datastore-name>/volumes/<disk-name>.vmdk
shell vmware-vdiskmanager -c -t 0 -s <size> -a lsilogic <disk-name>.vmdk
apiVersion: v1 kind: PersistentVolume metadata: name: pv1 1 spec: capacity: storage: 1Gi 2 accessModes: - ReadWriteOnce persistentVolumeReclaimPolicy: Retain vsphereVolume: 3 volumePath: "[datastore1] volumes/myDisk" 4 fsType: ext4 5
oc create -f pv1.yaml
apiVersion: v1 kind: PersistentVolumeClaim metadata: name: pvc1 1 spec: accessModes: - ReadWriteOnce 2 resources: requests: storage: "1Gi" 3 volumeName: pv1 4
oc create -f pvc1.yaml