Chapter 12. Using images 12.1. Using images overview Use the following topics to discover the different Source-to-Image (S2I), database, and other container images that are available for OpenShift Container Platform users. Red Hat official container images are provided in the Red Hat Registry at registry.redhat.io . OpenShift Container Platform's supported S2I, database, and Jenkins images are provided in the openshift4 repository in the Red Hat Quay Registry. For example, quay.io/openshift-release-dev/ocp-v4.0-<address> is the name of the OpenShift Application Platform image. The xPaaS middleware images are provided in their respective product repositories on the Red Hat Registry but suffixed with a -openshift . For example, registry.redhat.io/jboss-eap-6/eap64-openshift is the name of the JBoss EAP image. All Red Hat supported images covered in this section are described in the Container images section of the Red Hat Ecosystem Catalog . For every version of each image, you can find details on its contents and usage. Browse or search for the image that interests you. Important The newer versions of container images are not compatible with earlier versions of OpenShift Container Platform. Verify and use the correct version of container images, based on your version of OpenShift Container Platform. 12.2. Configuring Jenkins images OpenShift Container Platform provides a container image for running Jenkins. This image provides a Jenkins server instance, which can be used to set up a basic flow for continuous testing, integration, and delivery. The image is based on the Red Hat Universal Base Images (UBI). OpenShift Container Platform follows the LTS release of Jenkins. OpenShift Container Platform provides an image that contains Jenkins 2.x. The OpenShift Container Platform Jenkins images are available on Quay.io or registry.redhat.io . For example: USD podman pull registry.redhat.io/openshift4/ose-jenkins:<v4.3.0> To use these images, you can either access them directly from these registries or push them into your OpenShift Container Platform container image registry. Additionally, you can create an image stream that points to the image, either in your container image registry or at the external location. Your OpenShift Container Platform resources can then reference the image stream. But for convenience, OpenShift Container Platform provides image streams in the openshift namespace for the core Jenkins image as well as the example Agent images provided for OpenShift Container Platform integration with Jenkins. 12.2.1. Configuration and customization You can manage Jenkins authentication in two ways: OpenShift Container Platform OAuth authentication provided by the OpenShift Container Platform Login plugin. Standard authentication provided by Jenkins. 12.2.1.1. OpenShift Container Platform OAuth authentication OAuth authentication is activated by configuring options on the Configure Global Security panel in the Jenkins UI, or by setting the OPENSHIFT_ENABLE_OAUTH environment variable on the Jenkins Deployment configuration to anything other than false . This activates the OpenShift Container Platform Login plugin, which retrieves the configuration information from pod data or by interacting with the OpenShift Container Platform API server. Valid credentials are controlled by the OpenShift Container Platform identity provider. Jenkins supports both browser and non-browser access. Valid users are automatically added to the Jenkins authorization matrix at log in, where OpenShift Container Platform roles dictate the specific Jenkins permissions that users have. The roles used by default are the predefined admin , edit , and view . The login plugin executes self-SAR requests against those roles in the project or namespace that Jenkins is running in. Users with the admin role have the traditional Jenkins administrative user permissions. Users with the edit or view role have progressively fewer permissions. The default OpenShift Container Platform admin , edit , and view roles and the Jenkins permissions those roles are assigned in the Jenkins instance are configurable. When running Jenkins in an OpenShift Container Platform pod, the login plugin looks for a config map named openshift-jenkins-login-plugin-config in the namespace that Jenkins is running in. If this plugin finds and can read in that config map, you can define the role to Jenkins Permission mappings. Specifically: The login plugin treats the key and value pairs in the config map as Jenkins permission to OpenShift Container Platform role mappings. The key is the Jenkins permission group short ID and the Jenkins permission short ID, with those two separated by a hyphen character. If you want to add the Overall Jenkins Administer permission to an OpenShift Container Platform role, the key should be Overall-Administer . To get a sense of which permission groups and permissions IDs are available, go to the matrix authorization page in the Jenkins console and IDs for the groups and individual permissions in the table they provide. The value of the key and value pair is the list of OpenShift Container Platform roles the permission should apply to, with each role separated by a comma. If you want to add the Overall Jenkins Administer permission to both the default admin and edit roles, as well as a new Jenkins role you have created, the value for the key Overall-Administer would be admin,edit,jenkins . Note The admin user that is pre-populated in the OpenShift Container Platform Jenkins image with administrative privileges is not given those privileges when OpenShift Container Platform OAuth is used. To grant these permissions the OpenShift Container Platform cluster administrator must explicitly define that user in the OpenShift Container Platform identity provider and assigns the admin role to the user. Jenkins users' permissions that are stored can be changed after the users are initially established. The OpenShift Container Platform Login plugin polls the OpenShift Container Platform API server for permissions and updates the permissions stored in Jenkins for each user with the permissions retrieved from OpenShift Container Platform. If the Jenkins UI is used to update permissions for a Jenkins user, the permission changes are overwritten the time the plugin polls OpenShift Container Platform. You can control how often the polling occurs with the OPENSHIFT_PERMISSIONS_POLL_INTERVAL environment variable. The default polling interval is five minutes. The easiest way to create a new Jenkins service using OAuth authentication is to use a template. 12.2.1.2. Jenkins authentication Jenkins authentication is used by default if the image is run directly, without using a template. The first time Jenkins starts, the configuration is created along with the administrator user and password. The default user credentials are admin and password . Configure the default password by setting the JENKINS_PASSWORD environment variable when using, and only when using, standard Jenkins authentication. Procedure Create a Jenkins application that uses standard Jenkins authentication: USD oc new-app -e \ JENKINS_PASSWORD=<password> \ openshift4/ose-jenkins 12.2.2. Jenkins environment variables The Jenkins server can be configured with the following environment variables: Variable Definition Example values and settings OPENSHIFT_ENABLE_OAUTH Determines whether the OpenShift Container Platform Login plugin manages authentication when logging in to Jenkins. To enable, set to true . Default: false JENKINS_PASSWORD The password for the admin user when using standard Jenkins authentication. Not applicable when OPENSHIFT_ENABLE_OAUTH is set to true . Default: password JAVA_MAX_HEAP_PARAM , CONTAINER_HEAP_PERCENT , JENKINS_MAX_HEAP_UPPER_BOUND_MB These values control the maximum heap size of the Jenkins JVM. If JAVA_MAX_HEAP_PARAM is set, its value takes precedence. Otherwise, the maximum heap size is dynamically calculated as CONTAINER_HEAP_PERCENT of the container memory limit, optionally capped at JENKINS_MAX_HEAP_UPPER_BOUND_MB MiB. By default, the maximum heap size of the Jenkins JVM is set to 50% of the container memory limit with no cap. JAVA_MAX_HEAP_PARAM example setting: -Xmx512m CONTAINER_HEAP_PERCENT default: 0.5 , or 50% JENKINS_MAX_HEAP_UPPER_BOUND_MB example setting: 512 MiB JAVA_INITIAL_HEAP_PARAM , CONTAINER_INITIAL_PERCENT These values control the initial heap size of the Jenkins JVM. If JAVA_INITIAL_HEAP_PARAM is set, its value takes precedence. Otherwise, the initial heap size is dynamically calculated as CONTAINER_INITIAL_PERCENT of the dynamically calculated maximum heap size. By default, the JVM sets the initial heap size. JAVA_INITIAL_HEAP_PARAM example setting: -Xms32m CONTAINER_INITIAL_PERCENT example setting: 0.1 , or 10% CONTAINER_CORE_LIMIT If set, specifies an integer number of cores used for sizing numbers of internal JVM threads. Example setting: 2 JAVA_TOOL_OPTIONS Specifies options to apply to all JVMs running in this container. It is not recommended to override this value. Default: -XX:+UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap -Dsun.zip.disableMemoryMapping=true JAVA_GC_OPTS Specifies Jenkins JVM garbage collection parameters. It is not recommended to override this value. Default: -XX:+UseParallelGC -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=10 -XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=90 JENKINS_JAVA_OVERRIDES Specifies additional options for the Jenkins JVM. These options are appended to all other options, including the Java options above, and may be used to override any of them if necessary. Separate each additional option with a space; if any option contains space characters, escape them with a backslash. Example settings: -Dfoo -Dbar ; -Dfoo=first\ value -Dbar=second\ value . JENKINS_OPTS Specifies arguments to Jenkins. INSTALL_PLUGINS Specifies additional Jenkins plugins to install when the container is first run or when OVERRIDE_PV_PLUGINS_WITH_IMAGE_PLUGINS is set to true . Plugins are specified as a comma-delimited list of name:version pairs. Example setting: git:3.7.0,subversion:2.10.2 . OPENSHIFT_PERMISSIONS_POLL_INTERVAL Specifies the interval in milliseconds that the OpenShift Container Platform Login plugin polls OpenShift Container Platform for the permissions that are associated with each user that is defined in Jenkins. Default: 300000 - 5 minutes OVERRIDE_PV_CONFIG_WITH_IMAGE_CONFIG When running this image with an OpenShift Container Platform persistent volume (PV) for the Jenkins configuration directory, the transfer of configuration from the image to the PV is performed only the first time the image starts because the PV is assigned when the persistent volume claim (PVC) is created. If you create a custom image that extends this image and updates configuration in the custom image after the initial startup, the configuration is not copied over unless you set this environment variable to true . Default: false OVERRIDE_PV_PLUGINS_WITH_IMAGE_PLUGINS When running this image with an OpenShift Container Platform PV for the Jenkins configuration directory, the transfer of plugins from the image to the PV is performed only the first time the image starts because the PV is assigned when the PVC is created. If you create a custom image that extends this image and updates plugins in the custom image after the initial startup, the plugins are not copied over unless you set this environment variable to true . Default: false ENABLE_FATAL_ERROR_LOG_FILE When running this image with an OpenShift Container Platform PVC for the Jenkins configuration directory, this environment variable allows the fatal error log file to persist when a fatal error occurs. The fatal error file is saved at /var/lib/jenkins/logs . Default: false NODEJS_SLAVE_IMAGE Setting this value overrides the image that is used for the default Node.js agent pod configuration. A related image stream tag named jenkins-agent-nodejs is in the project. This variable must be set before Jenkins starts the first time for it to have an effect. Default Node.js agent image in Jenkins server: image-registry.openshift-image-registry.svc:5000/openshift/jenkins-agent-nodejs:latest MAVEN_SLAVE_IMAGE Setting this value overrides the image used for the default maven agent pod configuration. A related image stream tag named jenkins-agent-maven is in the project. This variable must be set before Jenkins starts the first time for it to have an effect. Default Maven agent image in Jenkins server: image-registry.openshift-image-registry.svc:5000/openshift/jenkins-agent-maven:latest 12.2.3. Providing Jenkins cross project access If you are going to run Jenkins somewhere other than your same project, you must provide an access token to Jenkins to access your project. Procedure Identify the secret for the service account that has appropriate permissions to access the project Jenkins must access: USD oc describe serviceaccount jenkins Example output Name: default Labels: <none> Secrets: { jenkins-token-uyswp } { jenkins-dockercfg-xcr3d } Tokens: jenkins-token-izv1u jenkins-token-uyswp In this case the secret is named jenkins-token-uyswp . Retrieve the token from the secret: USD oc describe secret <secret name from above> Example output Name: jenkins-token-uyswp Labels: <none> Annotations: kubernetes.io/service-account.name=jenkins,kubernetes.io/service-account.uid=32f5b661-2a8f-11e5-9528-3c970e3bf0b7 Type: kubernetes.io/service-account-token Data ==== ca.crt: 1066 bytes token: eyJhbGc..<content cut>....wRA The token parameter contains the token value Jenkins requires to access the project. 12.2.4. Jenkins cross volume mount points The Jenkins image can be run with mounted volumes to enable persistent storage for the configuration: /var/lib/jenkins is the data directory where Jenkins stores configuration files, including job definitions. 12.2.5. Customizing the Jenkins image through source-to-image To customize the official OpenShift Container Platform Jenkins image, you can use the image as a source-to-image (S2I) builder. You can use S2I to copy your custom Jenkins jobs definitions, add additional plugins, or replace the provided config.xml file with your own, custom, configuration. To include your modifications in the Jenkins image, you must have a Git repository with the following directory structure: plugins This directory contains those binary Jenkins plugins you want to copy into Jenkins. plugins.txt This file lists the plugins you want to install using the following syntax: configuration/jobs This directory contains the Jenkins job definitions. configuration/config.xml This file contains your custom Jenkins configuration. The contents of the configuration/ directory is copied to the /var/lib/jenkins/ directory, so you can also include additional files, such as credentials.xml , there. Sample build configuration customizes the Jenkins image in OpenShift Container Platform apiVersion: build.openshift.io/v1 kind: BuildConfig metadata: name: custom-jenkins-build spec: source: 1 git: uri: https://github.com/custom/repository type: Git strategy: 2 sourceStrategy: from: kind: ImageStreamTag name: jenkins:2 namespace: openshift type: Source output: 3 to: kind: ImageStreamTag name: custom-jenkins:latest 1 The source parameter defines the source Git repository with the layout described above. 2 The strategy parameter defines the original Jenkins image to use as a source image for the build. 3 The output parameter defines the resulting, customized Jenkins image that you can use in deployment configurations instead of the official Jenkins image. 12.2.6. Configuring the Jenkins Kubernetes plugin The OpenShift Container Platform Jenkins image includes the pre-installed Kubernetes plugin that allows Jenkins agents to be dynamically provisioned on multiple container hosts using Kubernetes and OpenShift Container Platform. To use the Kubernetes plugin, OpenShift Container Platform provides images that are suitable for use as Jenkins agents including the Base, Maven, and Node.js images. Both the Maven and Node.js agent images are automatically configured as Kubernetes pod template images within the OpenShift Container Platform Jenkins image configuration for the Kubernetes plugin. That configuration includes labels for each of the images that can be applied to any of your Jenkins jobs under their Restrict where this project can be run setting. If the label is applied, jobs run under an OpenShift Container Platform pod running the respective agent image. The Jenkins image also provides auto-discovery and auto-configuration of additional agent images for the Kubernetes plugin. With the OpenShift Container Platform sync plugin, the Jenkins image on Jenkins startup searches for the following within the project that it is running or the projects specifically listed in the plugin's configuration: Image streams that have the label role set to jenkins-agent . Image stream tags that have the annotation role set to jenkins-agent . Config maps that have the label role set to jenkins-agent . When it finds an image stream with the appropriate label, or image stream tag with the appropriate annotation, it generates the corresponding Kubernetes plugin configuration so you can assign your Jenkins jobs to run in a pod that runs the container image that is provided by the image stream. The name and image references of the image stream or image stream tag are mapped to the name and image fields in the Kubernetes plugin pod template. You can control the label field of the Kubernetes plugin pod template by setting an annotation on the image stream or image stream tag object with the key agent-label . Otherwise, the name is used as the label. Note Do not log in to the Jenkins console and modify the pod template configuration. If you do so after the pod template is created, and the OpenShift Container Platform Sync plugin detects that the image associated with the image stream or image stream tag has changed, it replaces the pod template and overwrites those configuration changes. You cannot merge a new configuration with the existing configuration. Consider the config map approach if you have more complex configuration needs. When it finds a config map with the appropriate label, it assumes that any values in the key-value data payload of the config map contains Extensible Markup Language (XML) that is consistent with the configuration format for Jenkins and the Kubernetes plugin pod templates. A key differentiator to note when using config maps, instead of image streams or image stream tags, is that you can control all the parameters of the Kubernetes plugin pod template. Sample config map for jenkins-agent kind: ConfigMap apiVersion: v1 metadata: name: jenkins-agent labels: role: jenkins-agent data: template1: |- <org.csanchez.jenkins.plugins.kubernetes.PodTemplate> <inheritFrom></inheritFrom> <name>template1</name> <instanceCap>2147483647</instanceCap> <idleMinutes>0</idleMinutes> <label>template1</label> <serviceAccount>jenkins</serviceAccount> <nodeSelector></nodeSelector> <volumes/> <containers> <org.csanchez.jenkins.plugins.kubernetes.ContainerTemplate> <name>jnlp</name> <image>openshift/jenkins-agent-maven-35-centos7:v3.10</image> <privileged>false</privileged> <alwaysPullImage>true</alwaysPullImage> <workingDir>/tmp</workingDir> <command></command> <args>USD{computer.jnlpmac} USD{computer.name}</args> <ttyEnabled>false</ttyEnabled> <resourceRequestCpu></resourceRequestCpu> <resourceRequestMemory></resourceRequestMemory> <resourceLimitCpu></resourceLimitCpu> <resourceLimitMemory></resourceLimitMemory> <envVars/> </org.csanchez.jenkins.plugins.kubernetes.ContainerTemplate> </containers> <envVars/> <annotations/> <imagePullSecrets/> <nodeProperties/> </org.csanchez.jenkins.plugins.kubernetes.PodTemplate> Note If you log in to the Jenkins console and make further changes to the pod template configuration after the pod template is created, and the OpenShift Container Platform Sync plugin detects that the config map has changed, it will replace the pod template and overwrite those configuration changes. You cannot merge a new configuration with the existing configuration. Do not log in to the Jenkins console and modify the pod template configuration. If you do so after the pod template is created, and the OpenShift Container Platform Sync plugin detects that the image associated with the image stream or image stream tag has changed, it replaces the pod template and overwrites those configuration changes. You cannot merge a new configuration with the existing configuration. Consider the config map approach if you have more complex configuration needs. After it is installed, the OpenShift Container Platform Sync plugin monitors the API server of OpenShift Container Platform for updates to image streams, image stream tags, and config maps and adjusts the configuration of the Kubernetes plugin. The following rules apply: Removing the label or annotation from the config map, image stream, or image stream tag results in the deletion of any existing PodTemplate from the configuration of the Kubernetes plugin. If those objects are removed, the corresponding configuration is removed from the Kubernetes plugin. Either creating appropriately labeled or annotated ConfigMap , ImageStream , or ImageStreamTag objects, or the adding of labels after their initial creation, leads to creating of a PodTemplate in the Kubernetes-plugin configuration. In the case of the PodTemplate by config map form, changes to the config map data for the PodTemplate are applied to the PodTemplate settings in the Kubernetes plugin configuration and overrides any changes that were made to the PodTemplate through the Jenkins UI between changes to the config map. To use a container image as a Jenkins agent, the image must run the agent as an entrypoint. For more details about this, refer to the official Jenkins documentation . 12.2.7. Jenkins permissions If in the config map the <serviceAccount> element of the pod template XML is the OpenShift Container Platform service account used for the resulting pod, the service account credentials are mounted into the pod. The permissions are associated with the service account and control which operations against the OpenShift Container Platform master are allowed from the pod. Consider the following scenario with service accounts used for the pod, which is launched by the Kubernetes Plugin that runs in the OpenShift Container Platform Jenkins image. If you use the example template for Jenkins that is provided by OpenShift Container Platform, the jenkins service account is defined with the edit role for the project Jenkins runs in, and the master Jenkins pod has that service account mounted. The two default Maven and NodeJS pod templates that are injected into the Jenkins configuration are also set to use the same service account as the Jenkins master. Any pod templates that are automatically discovered by the OpenShift Container Platform sync plugin because their image streams or image stream tags have the required label or annotations are configured to use the Jenkins master service account as their service account. For the other ways you can provide a pod template definition into Jenkins and the Kubernetes plugin, you have to explicitly specify the service account to use. Those other ways include the Jenkins console, the podTemplate pipeline DSL that is provided by the Kubernetes plugin, or labeling a config map whose data is the XML configuration for a pod template. If you do not specify a value for the service account, the default service account is used. Ensure that whatever service account is used has the necessary permissions, roles, and so on defined within OpenShift Container Platform to manipulate whatever projects you choose to manipulate from the within the pod. 12.2.8. Creating a Jenkins service from a template Templates provide parameter fields to define all the environment variables with predefined default values. OpenShift Container Platform provides templates to make creating a new Jenkins service easy. The Jenkins templates should be registered in the default openshift project by your cluster administrator during the initial cluster setup. The two available templates both define deployment configuration and a service. The templates differ in their storage strategy, which affects whether or not the Jenkins content persists across a pod restart. Note A pod might be restarted when it is moved to another node or when an update of the deployment configuration triggers a redeployment. jenkins-ephemeral uses ephemeral storage. On pod restart, all data is lost. This template is only useful for development or testing. jenkins-persistent uses a Persistent Volume (PV) store. Data survives a pod restart. To use a PV store, the cluster administrator must define a PV pool in the OpenShift Container Platform deployment. After you select which template you want, you must instantiate the template to be able to use Jenkins. Procedure Create a new Jenkins application using one of the following methods: A PV: USD oc new-app jenkins-persistent Or an emptyDir type volume where configuration does not persist across pod restarts: USD oc new-app jenkins-ephemeral 12.2.9. Using the Jenkins Kubernetes plugin In the following example, the openshift-jee-sample BuildConfig object causes a Jenkins Maven agent pod to be dynamically provisioned. The pod clones some Java source code, builds a WAR file, and causes a second BuildConfig , openshift-jee-sample-docker to run. The second BuildConfig layers the new WAR file into a container image. Sample BuildConfig that uses the Jenkins Kubernetes plugin kind: List apiVersion: v1 items: - kind: ImageStream apiVersion: image.openshift.io/v1 metadata: name: openshift-jee-sample - kind: BuildConfig apiVersion: build.openshift.io/v1 metadata: name: openshift-jee-sample-docker spec: strategy: type: Docker source: type: Docker dockerfile: |- FROM openshift/wildfly-101-centos7:latest COPY ROOT.war /wildfly/standalone/deployments/ROOT.war CMD USDSTI_SCRIPTS_PATH/run binary: asFile: ROOT.war output: to: kind: ImageStreamTag name: openshift-jee-sample:latest - kind: BuildConfig apiVersion: build.openshift.io/v1 metadata: name: openshift-jee-sample spec: strategy: type: JenkinsPipeline jenkinsPipelineStrategy: jenkinsfile: |- node("maven") { sh "git clone https://github.com/openshift/openshift-jee-sample.git ." sh "mvn -B -Popenshift package" sh "oc start-build -F openshift-jee-sample-docker --from-file=target/ROOT.war" } triggers: - type: ConfigChange It is also possible to override the specification of the dynamically created Jenkins agent pod. The following is a modification to the example, which overrides the container memory and specifies an environment variable. Sample BuildConfig that uses the Jenkins Kubernetes Plugin, specifying memory limit and environment variable kind: BuildConfig apiVersion: build.openshift.io/v1 metadata: name: openshift-jee-sample spec: strategy: type: JenkinsPipeline jenkinsPipelineStrategy: jenkinsfile: |- podTemplate(label: "mypod", 1 cloud: "openshift", 2 inheritFrom: "maven", 3 containers: [ containerTemplate(name: "jnlp", 4 image: "openshift/jenkins-agent-maven-35-centos7:v3.10", 5 resourceRequestMemory: "512Mi", 6 resourceLimitMemory: "512Mi", 7 envVars: [ envVar(key: "CONTAINER_HEAP_PERCENT", value: "0.25") 8 ]) ]) { node("mypod") { 9 sh "git clone https://github.com/openshift/openshift-jee-sample.git ." sh "mvn -B -Popenshift package" sh "oc start-build -F openshift-jee-sample-docker --from-file=target/ROOT.war" } } triggers: - type: ConfigChange 1 A new pod template called mypod is defined dynamically. The new pod template name is referenced in the node stanza. 2 The cloud value must be set to openshift . 3 The new pod template can inherit its configuration from an existing pod template. In this case, inherited from the Maven pod template that is pre-defined by OpenShift Container Platform. 4 This example overrides values in the pre-existing container, and must be specified by name. All Jenkins agent images shipped with OpenShift Container Platform use the Container name jnlp . 5 Specify the container image name again. This is a known issue. 6 A memory request of 512 Mi is specified. 7 A memory limit of 512 Mi is specified. 8 An environment variable CONTAINER_HEAP_PERCENT , with value 0.25 , is specified. 9 The node stanza references the name of the defined pod template. By default, the pod is deleted when the build completes. This behavior can be modified with the plugin or within a pipeline Jenkinsfile. 12.2.10. Jenkins memory requirements When deployed by the provided Jenkins Ephemeral or Jenkins Persistent templates, the default memory limit is 1 Gi . By default, all other process that run in the Jenkins container cannot use more than a total of 512 MiB of memory. If they require more memory, the container halts. It is therefore highly recommended that pipelines run external commands in an agent container wherever possible. And if Project quotas allow for it, see recommendations from the Jenkins documentation on what a Jenkins master should have from a memory perspective. Those recommendations proscribe to allocate even more memory for the Jenkins master. It is recommended to specify memory request and limit values on agent containers created by the Jenkins Kubernetes plugin. Admin users can set default values on a per-agent image basis through the Jenkins configuration. The memory request and limit parameters can also be overridden on a per-container basis. You can increase the amount of memory available to Jenkins by overriding the MEMORY_LIMIT parameter when instantiating the Jenkins Ephemeral or Jenkins Persistent template. 12.2.11. Additional resources See Base image options for more information on the Red Hat Universal Base Images (UBI). 12.3. Jenkins agent OpenShift Container Platform provides three images that are suitable for use as Jenkins agents: the Base , Maven , and Node.js images. The first is a base image for Jenkins agents: It pulls in both the required tools, headless Java, the Jenkins JNLP client, and the useful ones including git , tar , zip , and nss among others. It establishes the JNLP agent as the entrypoint. It includes the oc client tooling for invoking command line operations from within Jenkins jobs. It provides Dockerfiles for both Red Hat Enterprise Linux (RHEL) and localdev images. Two more images that extend the base image are also provided: Maven v3.5 image Node.js v10 image and Node.js v12 image The Maven and Node.js Jenkins agent images provide Dockerfiles for the Universal Base Image (UBI) that you can reference when building new agent images. Also note the contrib and contrib/bin subdirectories. They allow for the insertion of configuration files and executable scripts for your image. Important Use and extend an appropriate agent image version for the your of OpenShift Container Platform. If the oc client version that is embedded in the agent image is not compatible with the OpenShift Container Platform version, unexpected behavior can result. 12.3.1. Jenkins agent images The OpenShift Container Platform Jenkins agent images are available on Quay.io or registry.redhat.io . Jenkins images are available through the Red Hat Registry: USD docker pull registry.redhat.io/openshift4/ose-jenkins:<v4.5.0> USD docker pull registry.redhat.io/openshift4/jenkins-agent-nodejs-10-rhel7:<v4.5.0> USD docker pull registry.redhat.io/openshift4/jenkins-agent-nodejs-12-rhel7:<v4.5.0> USD docker pull registry.redhat.io/openshift4/ose-jenkins-agent-maven:<v4.5.0> USD docker pull registry.redhat.io/openshift4/ose-jenkins-agent-base:<v4.5.0> To use these images, you can either access them directly from Quay.io or registry.redhat.io or push them into your OpenShift Container Platform container image registry. 12.3.2. Jenkins agent environment variables Each Jenkins agent container can be configured with the following environment variables. Variable Definition Example values and settings JAVA_MAX_HEAP_PARAM , CONTAINER_HEAP_PERCENT , JENKINS_MAX_HEAP_UPPER_BOUND_MB These values control the maximum heap size of the Jenkins JVM. If JAVA_MAX_HEAP_PARAM is set, its value takes precedence. Otherwise, the maximum heap size is dynamically calculated as CONTAINER_HEAP_PERCENT of the container memory limit, optionally capped at JENKINS_MAX_HEAP_UPPER_BOUND_MB MiB. By default, the maximum heap size of the Jenkins JVM is set to 50% of the container memory limit with no cap. JAVA_MAX_HEAP_PARAM example setting: -Xmx512m CONTAINER_HEAP_PERCENT default: 0.5 , or 50% JENKINS_MAX_HEAP_UPPER_BOUND_MB example setting: 512 MiB JAVA_INITIAL_HEAP_PARAM , CONTAINER_INITIAL_PERCENT These values control the initial heap size of the Jenkins JVM. If JAVA_INITIAL_HEAP_PARAM is set, its value takes precedence. Otherwise, the initial heap size is dynamically calculated as CONTAINER_INITIAL_PERCENT of the dynamically calculated maximum heap size. By default, the JVM sets the initial heap size. JAVA_INITIAL_HEAP_PARAM example setting: -Xms32m CONTAINER_INITIAL_PERCENT example setting: 0.1 , or 10% CONTAINER_CORE_LIMIT If set, specifies an integer number of cores used for sizing numbers of internal JVM threads. Example setting: 2 JAVA_TOOL_OPTIONS Specifies options to apply to all JVMs running in this container. It is not recommended to override this value. Default: -XX:+UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap -Dsun.zip.disableMemoryMapping=true JAVA_GC_OPTS Specifies Jenkins JVM garbage collection parameters. It is not recommended to override this value. Default: -XX:+UseParallelGC -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=10 -XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=90 JENKINS_JAVA_OVERRIDES Specifies additional options for the Jenkins JVM. These options are appended to all other options, including the Java options above, and can be used to override any of them, if necessary. Separate each additional option with a space and if any option contains space characters, escape them with a backslash. Example settings: -Dfoo -Dbar ; -Dfoo=first\ value -Dbar=second\ value USE_JAVA_VERSION Specifies the version of Java version to use to run the agent in its container. The container base image has two versions of java installed: java-11 and java-1.8.0 . If you extend the container base image, you can specify any alternative version of java using its associated suffix. The default value is java-11 . Example setting: java-1.8.0 12.3.3. Jenkins agent memory requirements A JVM is used in all Jenkins agents to host the Jenkins JNLP agent as well as to run any Java applications such as javac , Maven, or Gradle. By default, the Jenkins JNLP agent JVM uses 50% of the container memory limit for its heap. This value can be modified by the CONTAINER_HEAP_PERCENT environment variable. It can also be capped at an upper limit or overridden entirely. By default, any other processes run in the Jenkins agent container, such as shell scripts or oc commands run from pipelines, cannot use more than the remaining 50% memory limit without provoking an OOM kill. By default, each further JVM process that runs in a Jenkins agent container uses up to 25% of the container memory limit for its heap. It might be necessary to tune this limit for many build workloads. 12.3.4. Jenkins agent Gradle builds Hosting Gradle builds in the Jenkins agent on OpenShift Container Platform presents additional complications because in addition to the Jenkins JNLP agent and Gradle JVMs, Gradle spawns a third JVM to run tests if they are specified. The following settings are suggested as a starting point for running Gradle builds in a memory constrained Jenkins agent on OpenShift Container Platform. You can modify these settings as required. Ensure the long-lived Gradle daemon is disabled by adding org.gradle.daemon=false to the gradle.properties file. Disable parallel build execution by ensuring org.gradle.parallel=true is not set in the gradle.properties file and that --parallel is not set as a command line argument. To prevent Java compilations running out-of-process, set java { options.fork = false } in the build.gradle file. Disable multiple additional test processes by ensuring test { maxParallelForks = 1 } is set in the build.gradle file. Override the Gradle JVM memory parameters by the GRADLE_OPTS , JAVA_OPTS or JAVA_TOOL_OPTIONS environment variables. Set the maximum heap size and JVM arguments for any Gradle test JVM by defining the maxHeapSize and jvmArgs settings in build.gradle , or through the -Dorg.gradle.jvmargs command line argument. 12.3.5. Jenkins agent pod retention Jenkins agent pods, are deleted by default after the build completes or is stopped. This behavior can be changed by the Kubernetes plugin pod retention setting. Pod retention can be set for all Jenkins builds, with overrides for each pod template. The following behaviors are supported: Always keeps the build pod regardless of build result. Default uses the plugin value, which is the pod template only. Never always deletes the pod. On Failure keeps the pod if it fails during the build. You can override pod retention in the pipeline Jenkinsfile: podTemplate(label: "mypod", cloud: "openshift", inheritFrom: "maven", podRetention: onFailure(), 1 containers: [ ... ]) { node("mypod") { ... } } 1 Allowed values for podRetention are never() , onFailure() , always() , and default() . Warning Pods that are kept might continue to run and count against resource quotas. 12.4. Source-to-image You can use the Red Hat Software Collections images as a foundation for applications that rely on specific runtime environments such as Node.js, Perl, or Python. You can use the Red Hat Java Source-to-Image for OpenShift documentation as a reference for runtime environments that use Java. Special versions of some of these runtime base images are referred to as Source-to-Image (S2I) images. With S2I images, you can insert your code into a base image environment that is ready to run that code. S2I images include: .NET Java Go Node.js Perl PHP Python Ruby S2I images are available for you to use directly from the OpenShift Container Platform web console by following procedure: Log in to the OpenShift Container Platform web console using your login credentials. The default view for the OpenShift Container Platform web console is the Administrator perspective. Use the perspective switcher to switch to the Developer perspective. In the +Add view, select an existing project from the list or use the Project drop-down list to create a new project. Choose All services under the tile Developer Catalog . Select the Type Builder Images then can see the available S2I images. S2I images are also available though the Configuring the Cluster Samples Operator . 12.4.1. Source-to-image build process overview Source-to-image (S2I) produces ready-to-run images by injecting source code into a container that prepares that source code to be run. It performs the following steps: Runs the FROM <builder image> command Copies the source code to a defined location in the builder image Runs the assemble script in the builder image Sets the run script in the builder image as the default command Buildah then creates the container image. 12.4.2. Additional resources For instructions on using the Cluster Samples Operator, see the Configuring the Cluster Samples Operator . For more information on S2I builds, see the builds strategy documentation on S2I builds . For troubleshooting assistance for the S2I process, see Troubleshooting the Source-to-Image process . For an overview of creating images with S2I, see Creating images from source code with source-to-image . For an overview of testing S2I images, see About testing S2I images . 12.5. Customizing source-to-image images Source-to-image (S2I) builder images include assemble and run scripts, but the default behavior of those scripts is not suitable for all users. You can customize the behavior of an S2I builder that includes default scripts. 12.5.1. Invoking scripts embedded in an image Builder images provide their own version of the source-to-image (S2I) scripts that cover the most common use-cases. If these scripts do not fulfill your needs, S2I provides a way of overriding them by adding custom ones in the .s2i/bin directory. However, by doing this, you are completely replacing the standard scripts. In some cases, replacing the scripts is acceptable, but, in other scenarios, you can run a few commands before or after the scripts while retaining the logic of the script provided in the image. To reuse the standard scripts, you can create a wrapper script that runs custom logic and delegates further work to the default scripts in the image. Procedure Look at the value of the io.openshift.s2i.scripts-url label to determine the location of the scripts inside of the builder image: USD podman inspect --format='{{ index .Config.Labels "io.openshift.s2i.scripts-url" }}' wildfly/wildfly-centos7 Example output image:///usr/libexec/s2i You inspected the wildfly/wildfly-centos7 builder image and found out that the scripts are in the /usr/libexec/s2i directory. Create a script that includes an invocation of one of the standard scripts wrapped in other commands: .s2i/bin/assemble script #!/bin/bash echo "Before assembling" /usr/libexec/s2i/assemble rc=USD? if [ USDrc -eq 0 ]; then echo "After successful assembling" else echo "After failed assembling" fi exit USDrc This example shows a custom assemble script that prints the message, runs the standard assemble script from the image, and prints another message depending on the exit code of the assemble script. Important When wrapping the run script, you must use exec for invoking it to ensure signals are handled properly. The use of exec also precludes the ability to run additional commands after invoking the default image run script. .s2i/bin/run script #!/bin/bash echo "Before running application" exec /usr/libexec/s2i/run

Commands:
podman pull registry.redhat.io/openshift4/ose-jenkins:<v4.3.0>
oc new-app -e JENKINS_PASSWORD=<password> openshift4/ose-jenkins
oc describe serviceaccount jenkins
Name: default Labels: <none> Secrets: { jenkins-token-uyswp } { jenkins-dockercfg-xcr3d } Tokens: jenkins-token-izv1u jenkins-token-uyswp
oc describe secret <secret name from above>
Name: jenkins-token-uyswp Labels: <none> Annotations: kubernetes.io/service-account.name=jenkins,kubernetes.io/service-account.uid=32f5b661-2a8f-11e5-9528-3c970e3bf0b7 Type: kubernetes.io/service-account-token Data ==== ca.crt: 1066 bytes token: eyJhbGc..<content cut>....wRA
pluginId:pluginVersion
apiVersion: build.openshift.io/v1 kind: BuildConfig metadata: name: custom-jenkins-build spec: source: 1 git: uri: https://github.com/custom/repository type: Git strategy: 2 sourceStrategy: from: kind: ImageStreamTag name: jenkins:2 namespace: openshift type: Source output: 3 to: kind: ImageStreamTag name: custom-jenkins:latest
kind: ConfigMap apiVersion: v1 metadata: name: jenkins-agent labels: role: jenkins-agent data: template1: |- <org.csanchez.jenkins.plugins.kubernetes.PodTemplate> <inheritFrom></inheritFrom> <name>template1</name> <instanceCap>2147483647</instanceCap> <idleMinutes>0</idleMinutes> <label>template1</label> <serviceAccount>jenkins</serviceAccount> <nodeSelector></nodeSelector> <volumes/> <containers> <org.csanchez.jenkins.plugins.kubernetes.ContainerTemplate> <name>jnlp</name> <image>openshift/jenkins-agent-maven-35-centos7:v3.10</image> <privileged>false</privileged> <alwaysPullImage>true</alwaysPullImage> <workingDir>/tmp</workingDir> <command></command> <args>USD{computer.jnlpmac} USD{computer.name}</args> <ttyEnabled>false</ttyEnabled> <resourceRequestCpu></resourceRequestCpu> <resourceRequestMemory></resourceRequestMemory> <resourceLimitCpu></resourceLimitCpu> <resourceLimitMemory></resourceLimitMemory> <envVars/> </org.csanchez.jenkins.plugins.kubernetes.ContainerTemplate> </containers> <envVars/> <annotations/> <imagePullSecrets/> <nodeProperties/> </org.csanchez.jenkins.plugins.kubernetes.PodTemplate>
oc new-app jenkins-persistent
oc new-app jenkins-ephemeral
kind: List apiVersion: v1 items: - kind: ImageStream apiVersion: image.openshift.io/v1 metadata: name: openshift-jee-sample - kind: BuildConfig apiVersion: build.openshift.io/v1 metadata: name: openshift-jee-sample-docker spec: strategy: type: Docker source: type: Docker dockerfile: |- FROM openshift/wildfly-101-centos7:latest COPY ROOT.war /wildfly/standalone/deployments/ROOT.war CMD USDSTI_SCRIPTS_PATH/run binary: asFile: ROOT.war output: to: kind: ImageStreamTag name: openshift-jee-sample:latest - kind: BuildConfig apiVersion: build.openshift.io/v1 metadata: name: openshift-jee-sample spec: strategy: type: JenkinsPipeline jenkinsPipelineStrategy: jenkinsfile: |- node("maven") { sh "git clone https://github.com/openshift/openshift-jee-sample.git ." sh "mvn -B -Popenshift package" sh "oc start-build -F openshift-jee-sample-docker --from-file=target/ROOT.war" } triggers: - type: ConfigChange
kind: BuildConfig apiVersion: build.openshift.io/v1 metadata: name: openshift-jee-sample spec: strategy: type: JenkinsPipeline jenkinsPipelineStrategy: jenkinsfile: |- podTemplate(label: "mypod", 1 cloud: "openshift", 2 inheritFrom: "maven", 3 containers: [ containerTemplate(name: "jnlp", 4 image: "openshift/jenkins-agent-maven-35-centos7:v3.10", 5 resourceRequestMemory: "512Mi", 6 resourceLimitMemory: "512Mi", 7 envVars: [ envVar(key: "CONTAINER_HEAP_PERCENT", value: "0.25") 8 ]) ]) { node("mypod") { 9 sh "git clone https://github.com/openshift/openshift-jee-sample.git ." sh "mvn -B -Popenshift package" sh "oc start-build -F openshift-jee-sample-docker --from-file=target/ROOT.war" } } triggers: - type: ConfigChange
docker pull registry.redhat.io/openshift4/ose-jenkins:<v4.5.0>
docker pull registry.redhat.io/openshift4/jenkins-agent-nodejs-10-rhel7:<v4.5.0>
docker pull registry.redhat.io/openshift4/jenkins-agent-nodejs-12-rhel7:<v4.5.0>
docker pull registry.redhat.io/openshift4/ose-jenkins-agent-maven:<v4.5.0>
docker pull registry.redhat.io/openshift4/ose-jenkins-agent-base:<v4.5.0>
podTemplate(label: "mypod", cloud: "openshift", inheritFrom: "maven", podRetention: onFailure(), 1 containers: [ ]) { node("mypod") { } }
podman inspect --format='{{ index .Config.Labels "io.openshift.s2i.scripts-url" }}' wildfly/wildfly-centos7
image:///usr/libexec/s2i
#!/bin/bash echo "Before assembling" /usr/libexec/s2i/assemble rc=USD? if [ USDrc -eq 0 ]; then echo "After successful assembling" else echo "After failed assembling" fi exit USDrc
#!/bin/bash echo "Before running application" exec /usr/libexec/s2i/run