There are at least three different ways to pursue Jenkins integration with OpenShift Enterprise version 2.
1. Use OpenShift’s built-in Jenkins capability. You can push source code to the OpenShift gear directly and allow an embedded Jenkins client to handle compilation and deployment of the code. For more details on this, see the Continuous Integration section on the OpenShift Developer Portal.
2. Binary deployment via OpenShift API and Git push. Create a script job in Jenkins that uses the OpenShift REST API or CLI to create the gear, then use the Git URL of the created gear returned by the REST call to push a binary deployment.
3. Jenkins OpenShift Deployer Plugin. The community open source Jenkins OpenShift Deployer plugin allows a Jenkins job to create OpenShift containers and deploy applications to it. The Jenkins job is configured through the Jenkins UI rather than through a custom script.
Most enterprises will want to run Jenkins in a centralized server/cluster external to the PaaS containers that host the applications. OpenShift itself could be the hosting environment for that Jenkins cluster, but it would likely run in a separate OpenShift Enterprise environment and feed releases to the DEV, TEST, and PROD OpenShift Enterprise environments that host and autoscale the applications.
That means either handling your own integration between Jenkins and OpenShift Enterprise use the OpenShift REST API and Git API or using a third-party tool like the open source community Jenkins OpenShift Deployer.
The OpenShift Deployer worked well for the use case I’ve deen demo’ing. It’s simply a matter of configuring the connection and SSH keys for the OpenShift environments that Jenkins will communicate with and then tying that OpenShift broker into a build’s deployment job. Here is a screenshot of the configuration of OpenShift servers in the Manage Jenkins > Configure System screen:
As you can see, the plugin allows you to test your credentials against the broker for the OpenShift Enterprise environment you’re configuration and even upload the Jenkins server’s public SSH key to the broker. The plugin will log in with your credentials and upload the SSH key so that Jenkins can automatically drive deployments to your OpenShift environment with no human intervention.
With that in place, you can configure a build job to deploy to OpenShift. Here is the snippet from the build job (in this case the one that corresponds to the Acceptance stage of our deployment pipeline) that deploys the application on OpenShift:
The Deployment Type is GIT, which signifies to the plugin that this is not a deployable zipped as a .tar.gz archive. The actual deployment package is listed in the current directory, which is where the package was moved to by an earlier step. In a real enterprise environment, this would contain a URL to the location of the package in an artifact repository like Nexus.
With Jenkins/OpenShift integration, you have two powerful tools of automation in a deployment pipeline working hand-in-hand.