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A Sample OpenShift Pipeline

This example demonstrates how to implement a full end-to-end Jenkins Pipeline for a Java application in OpenShift Container Platform. This sample demonstrates the following capabilities:

  • Deploying an integrated Jenkins server inside of OpenShift
  • Running both custom and oob Jenkins slaves as pods in OpenShift
  • "One Click" instantiation of a Jenkins Pipeline using OpenShift's Jenkins Pipeline Strategy feature
  • Promotion of an application's container image within an OpenShift Cluster (using oc tag)
  • Promotion of an application's container image to a separate OpenShift Cluster (using skopeo)

Quickstart

Requirements

  1. OpenShift Applier git clone git@github.com:redhat-cop/casl-ansible.git git checkout v3.6.1
  2. Ansible sudo dnf install ansible

Installation

Run the following commands to instantiate this example.

ansible-playbook -i inventory/hosts ../casl-ansible/playbooks/openshift-cluster-seed.yml --connection=local

The above command will create all the necessary projects and OpenShift objects as well as a Jenkins instance that will build, promote and deploy the application. Run the following commands to instantiate this example.

Architecture

OpenShift Templates

The components of this pipeline are divided into two templates.

The first template, files/builds/template.yml is what we are calling the "Build" template. It contains:

  • A jenkinsPipelineStrategy BuildConfig
  • An s2i BuildConfig
  • An ImageStream for the s2i build config to push to

The build template contains a default source code repo for a java application compatible with this pipelines architecture (https://github.com/etsauer/ticket-monster).

The second template, files/deployment/template.yml is the "Deploy" template. It contains:

  • A tomcat8 DeploymentConfig
  • A Service definition
  • A Route

The idea behind the split between the templates is that I can deploy the build template only once (to my dev project) and that the pipeline will promote my image through all of the various stages of my application's lifecycle. The deployment template gets deployed once to each of the stages of the application lifecycle (once per OpenShift project).

Pipeline Script

This project includes a sample pipeline.groovy Jenkins Pipeline script that could be included with a Java project in order to implement a basic CI/CD pipeline for that project, under the following assumptions:

  • The project is built with Maven
  • The pipeline.groovy script is placed in the same directory as the pom.xml file in the git source.
  • The OpenShift projects that represent the Application's lifecycle stages are of the naming format: <app-name>-dev, <app-name>-stage, <app-name>-prod.

For convenience, this pipeline script is already included in the following git repository, based on the JBoss Developers Ticket Monster app.

https://github.com/etsauer/ticket-monster

Bill of Materials

  • One or Two OpenShift Container Platform Clusters
    • OpenShift 3.5+ is required.
  • Access to GitHub

Implementation Instructions

1. Create Lifecycle Stages

For the purposes of this demo, we are going to create three stages for our application to be promoted through.

  • basic-tomcat-build
  • basic-tomcat-dev
  • basic-tomcat-stage
  • basic-tomcat-prod

In the spirit of Infrastructure as Code we have a YAML file that defines the ProjectRequests for us. This is as an alternative to running oc new-project, but will yeild the same result.

2. Stand up Jenkins master in build

For this step, the OpenShift default template set provides exactly what we need to get jenkins up and running. Jenkins will be running in the build project and promote and deploy to the basic-tomcat-dev project.

4. Instantiate Pipeline

A deploy template is provided at deploy/basic-tomcat-template.yml that defines all of the resources required to run our Tomcat application. It includes:

  • A Service
  • A Route
  • An ImageStream
  • A DeploymentConfig
  • A RoleBinding to allow Jenkins to deploy in each namespace.

This template should be instantiated once in each of the namespaces that our app will be deployed to. For this purpose, we have created a param file to be fed to oc process to customize the template for each environment.

A build template is provided at files/builds/template.yml that defines all the resources required to build our java app. It includes:

  • A BuildConfig that defines a JenkinsPipelineStrategy build, which will be used to define out pipeline.
  • A BuildConfig that defines a Source build with Binary input. This will build our image.

At this point you should be able to go to the Web Console and follow the pipeline by clicking in your myapp-dev project, and going to Builds -> Pipelines. At several points you will be prompted for input on the pipeline. You can interact with it by clicking on the input required link, which takes you to Jenkins, where you can click the Proceed button. By the time you get through the end of the pipeline you should be able to visit the Route for your app deployed to the myapp-prod project to confirm that your image has been promoted through all stages.

Cleanup

Cleaning up this example is as simple as deleting the projects we created at the beginning.

oc delete project basic-tomcat-build basic-tomcat-dev basic-tomcat-prod basic-tomcat-stage