1. Introduction

The ER-Demo allows for provisioning from either source via CI/CD pipelines or from tagged binary images hosted in the Quay container image repository.

This document is a deep-dive into the former approach: Provisioning from source using CI/CD pipelines.

2. Jenkins Scripted vs Declarative Pipelines

Jenkins pipelines can be written in either a Scripted or Declarative approach.

The pipelines in the ER-Demo make use of the Declarative approach.

3. Jenkins Master node

4. Jenkins Worker Nodes

Reference - https://docs.openshift.com/container-platform/4.5/openshift_images/using_images/images-other-jenkins.html#images-other-jenkins-config-kubernetes_images-other-jenkins

Auto-Discovery

The Jenkins image also provides auto-discovery and auto-configuration of slave images for the Kubernetes plug-in. With the OpenShift Sync plug-in, the Jenkins image on Jenkins start-up searches within the project that it is running, or the projects specifically listed in the plug-in’s configuration for the following:

Image streams that have the label role set to jenkins-slave.

Image stream tags that have the annotation role set to jenkins-slave.

ConfigMaps that have the label role set to jenkins-slave.

When it finds an image stream with the appropriate label, or image stream tag with the appropriate annotation, it generates the corresponding Kubernetes plug-in configuration so you can assign your Jenkins jobs to run in a pod running the container image provided by the image stream.

$ oc get cm jenkins-maven-slave -o json | jq .metadata.labels.role

"jenkins-slave"

oc get cm jenkins-maven-slave -o yaml | more

oc get pvc jenkins-maven-slave-repository

Integration with Nexus

        <envVars>
            <org.csanchez.jenkins.plugins.kubernetes.model.KeyValueEnvVar>
              <key>MAVEN_MIRROR_URL</key>
              <value>http://nexus.user1-er-tools.svc:8081/content/groups/public</value>
            </org.csanchez.jenkins.plugins.kubernetes.model.KeyValueEnvVar>
        </envVars>

maven-with-nexus

#jenkins_maven_slave_configmap_image: image-registry.openshift-image-registry.svc:5000/openshift/jenkins-agent-maven:latest jenkins_maven_slave_configmap_image: quay.io/emergencyresponsedemo/jenkins_slave_upgraded_mvn:1.0