The use of CI tooling is often required to gain the full benefit of continuous integration. Jenkins is a popular CI tool, with support for build and deployment to OpenShift environments through plugins and other approaches. Openshift provides a supported Jenkins image. Refer to the official OpenShift documentation for details on using this image.

This reference architecture explores two scenarios:

There are two major differences in terms of the functionality and usage of the Jenkins image, compared to the Jenkins installation outside of OpenShift:

As documented on OpenShift Pipeline Plugin project page:

If that project is also where Jenkins is running out of, and hence you are using the OpenShift Jenkins image (https://github.com/openshift/jenkins[https://github.com/openshift/jenkins]), then the bearer authorization token associated with that service account is already made available to the plugin (mounted into the container Jenkins is running in at "/run/secrets/kubernetes.io/serviceaccount/token"). So you don't need to specify it in the various build step config panels.

Here is one example of configuring the Trigger OpenShift Build step on the Jenkins image. In contrast to the standalone Jenkins configuration, the only value that needs to be configured here is the BuildConfig name.

However, there is still no new-app functionality in the Jenkins console. In order to start a new OpenShift application, either run the oc new-app directly in OpenShift before using the Jenkins image, or tigger it from the Jenkins console using Execute Shell.

Below is an example of triggering new-app from the Jenkins console:

Console output:

[workspace] $ /bin/sh -xe /tmp/hudson6043280415050924590.sh
+ oc new-app jboss-eap70-openshift:latest~. --name=presentation
--> Found image 926ec6a (11 weeks old) in image stream "openshift/jboss-eap70-openshift" under tag "latest" for "jboss-eap70-openshift:latest"

    JBoss EAP 7.0
    -------------
    Platform for building and running JavaEE applications on JBoss EAP 7.0

    Tags: builder, javaee, eap, eap7

    * A source build using binary input will be created
      * The resulting image will be pushed to image stream "presentation:latest"
      * A binary build was created, use 'start-build --from-dir' to trigger a new build
    * This image will be deployed in deployment config "presentation"
    * Ports 8080/tcp, 8443/tcp, 8778/tcp will be load balanced by service "presentation"
      * Other containers can access this service through the hostname "presentation"

--> Creating resources ...
    imagestream "presentation" created
    buildconfig "presentation" created
    deploymentconfig "presentation" created
    service "presentation" created
--> Success
    Use 'oc start-build presentation' to start a build.
    Run 'oc status' to view your app.
Finished: SUCCESS

$ oc new-app jenkins-persistent

$ oc new-app jenkins-ephemeral

The OpenShift Pipeline Plugin does not have native support for some functionalities, including the new-app and start-build features with binary source. However, there is a new Jenkins plugin with support for various CLI features. This plugin wraps the oc client component. The OpenShift Jenkins Pipeline (DSL) Plugin is not currently supported and this paper therefore places less focus on it.

This plugin provides easier integration with OpenShift; for example, an Openshift Cluster can be configured simply with URL, credentials and the default project name.

Sending custom command to OpenShift using this plugin is much easier. The oc command can be supplied after simply selecting the newly defined Openshift Cluster:

Job DSL is a very popular plugin for building Jenkins jobs. This plugin simplifies creating and managing pipelines and can define Jenkins jobs in plain text, using a Groovy-based domain specific language (DSL).

The DSL language output is a job configuration XML file (config.xml file under the job folder). DSL plugin provides high level API to work with this configuration file, and in the absence of high level API, the DSL supports configuration blocks to directly access the XML content of config.xml.

For example, we will explore using this DSL plugin to build the MSA project in an OpenShift environment.

First, install the Job DSL plugin from Manage Jenkins section of the administration web console.

After installation, create a DSL seed job that uses the Free-style project style to run the Scripts.

Seed jobs can use the DSL script directly in the console, or use a DSL script on the file system. In this example, a script from the file system is used, as it’s easier to edit, and the script can be stored in a Git repository.

Details of the MSA_DSL_seed.groovy script:

The script sets up five jobs, which are: MSA_DSL_create_all, MSA_DSL_redeploy_billing, MSA_DSL_redeploy_product, MSA_DSL_redeploy_sales and MSA_DSL_redeploy_presentation.

It uses configuration blocks to define the same customWorkspace for all five jobs, since they all apply to the same project.

    configure { project ->
        project / 'customWorkspace' << '${JENKINS_HOME}/workspace/MSA_DSL'
    }

The script then sets up all jobs to use the same repository, git://github.com/RHsyseng/MSA-EAP7-OSE.git, through the SCM API.

    scm {
        git('git://github.com/RHsyseng/MSA-EAP7-OSE.git')
    }

The following sections are similar to previous examples. The script uses the steps API to set up the build steps for each job, they will run a maven build, then will create services through a shell terminal, and finally deploy the war files through the oc client, which is installed locally next to Jenkins.

The full script content follows:

job('MSA_DSL_create_all') {

    configure { project ->
        project / 'customWorkspace' << '${JENKINS_HOME}/workspace/MSA_DSL'
    }

    scm {
        git('git://github.com/RHsyseng/MSA-EAP7-OSE.git')
    }

    steps {
        maven('-e clean package')

        shell('oc new-app -e MYSQL_USER=product -e MYSQL_PASSWORD=password -e MYSQL_DATABASE=product -e MYSQL_ROOT_PASSWORD=passwd mysql --name=product-db')
        shell('oc new-app -e MYSQL_USER=sales -e MYSQL_PASSWORD=password -e MYSQL_DATABASE=sales -e MYSQL_ROOT_PASSWORD=passwd mysql --name=sales-db')
        shell('mkdir -p /tmp/nocontent')
        shell('sleep 60')

        shell('oc new-app jboss-eap70-openshift:latest~/tmp/nocontent --name=billing-service')
        shell('oc start-build billing-service --from-file=Billing/target/billing.war')

        shell('mkdir Product/target/deploy')
        shell('cp Product/target/product.war Product/target/deploy')
        shell('cp -r Product/configuration Product/target/deploy')
        shell('oc new-app -e MYSQL_USER=product -e MYSQL_PASSWORD=password jboss-eap70-openshift:latest~/tmp/nocontent --name=product-service')
        shell('oc start-build product-service --from-dir=Product/target/deploy')

        shell('mkdir Sales/target/deploy')
        shell('cp Sales/target/sales.war Sales/target/deploy')
        shell('cp -r Sales/configuration Sales/target/deploy')
        shell('oc new-app -e MYSQL_USER=sales -e MYSQL_PASSWORD=password jboss-eap70-openshift:latest~/tmp/nocontent --name=sales-service')
        shell('oc start-build sales-service --from-dir=Sales/target/deploy')

        shell('oc new-app jboss-eap70-openshift:latest~/tmp/nocontent --name=presentation')
        shell('oc start-build presentation --from-file=Presentation/target/ROOT.war')

        shell('oc expose service presentation --hostname=msa.example.com')

    }
}

job('MSA_DSL_redeploy_billing') {
    configure { project ->
        project / 'customWorkspace' << '${JENKINS_HOME}/workspace/MSA_DSL'
    }


    scm {
        git('git://github.com/RHsyseng/MSA-EAP7-OSE.git')
    }

    steps {
        maven('-e clean package')
        shell('oc start-build billing-service --from-file=Billing/target/billing.war')
    }
}


job('MSA_DSL_redeploy_product') {
    configure { project ->
        project / 'customWorkspace' << '${JENKINS_HOME}/workspace/MSA_DSL'
    }


    scm {
        git('git://github.com/RHsyseng/MSA-EAP7-OSE.git')
    }

    steps {
        maven('-e clean package')
        shell('mkdir Product/target/deploy')
        shell('cp Product/target/product.war Product/target/deploy')
        shell('cp -r Product/configuration Product/target/deploy')
        shell('oc start-build product-service --from-dir=Product/target/deploy')

    }
}


job('MSA_DSL_redeploy_sales') {
    configure { project ->
        project / 'customWorkspace' << '${JENKINS_HOME}/workspace/MSA_DSL'
    }


    scm {
        git('git://github.com/RHsyseng/MSA-EAP7-OSE.git')
    }

    steps {
        maven('-e clean package')
        shell('mkdir Sales/target/deploy')
        shell('cp Sales/target/sales.war Sales/target/deploy')
        shell('cp -r Sales/configuration Sales/target/deploy')
        shell('oc start-build sales-service --from-dir=Sales/target/deploy')
    }
}

job('MSA_DSL_redeploy_presentation') {
    configure { project ->
        project / 'customWorkspace' << '${JENKINS_HOME}/workspace/MSA_DSL'
    }


    scm {
        git('git://github.com/RHsyseng/MSA-EAP7-OSE.git')
    }

    steps {
        maven('-e clean package')
        shell('oc start-build presentation --from-file=Presentation/target/ROOT.war')
    }
}

Building the MSA_seed project will generate these sub-projects:

Inside each sub-project, the SCM, Maven and build steps are already defined. They are ready to be executed.

As demonstrated through these example, the Job DSL plugin is a powerful and user friendly plugin that can be used with oc client for deployment on OpenShift. It uses Groovy-based scripts to create new jobs, can invoke other plugins through their API, and to perform any other required function that’s not defined in the existing API, it can use configuration blocks to achieve the same effect. The resulting scripts can be checked into a source code repository, and easily reused in different environments.