Deploy Helm charts with Jenkins CI/CD in Red Hat OpenShift 4

Helm is a package manager for Kubernetes. Helm uses a packaging format called charts, which include all of the Kubernetes resources that are required to deploy an application, such as deployments, services, ingress, etc. Helm charts are very useful for installing applications and performing upgrades on a Kubernetes cluster.

In this article, I will show you how to deploy a Helm chart using Jenkins continuous integration and continuous delivery (CI/CD) and Red Hat OpenShift 4. Figure 1 shows a high-level view of the process.

Diagram showing how a Helm chart is deployed to Red Hat OpenShift with Jenkins CI/CD.
Deploying Helm charts with Jenkins CI/CD.
Figure 1: Deploying Helm charts with Jenkins CI/CD.

Prerequisites

You will need to install the following technologies before beginning this exercise:

Deploy Jenkins

First, install Jenkins using either a template or the Developer Catalog on OpenShift:

  1. Assuming you have OpenShift Container Platform 4 in your development environment, navigate to Developer perspective in the OpenShift web console.
  2. Select Add from the Developer Catalog and search for Jenkins, then click Instantiate Template, as shown in Figure 2.
Screenshot showing how to install Jenkins using the Developer Catalog on Red Hat OpenShift.
Figure 2: Install Jenkins using the Developer Catalog on OpenShift.

Create a Jenkins agent image with the Helm client

This is required to run the helm CLI command in containers.

To create the agent with the Helm client, we will use ose-jenkins-agent-base as the base image:

  1. Create the Dockerfile:
    FROM registry.redhat.io/openshift4/ose-jenkins-agent-base
    
    COPY helm /usr/bin/helm  ---> untar helm-linux-amd64.tar.gz(Helm 3 CLI) to get helm client. 
    RUN chmod +x /usr/bin/helm
  2. Build the image:
    podman build -t quay.io/<User-ID>/jenkins-helm-agent:v0.1 .
  3. Push the image to the repository:
    podman push quay.io/<USER-ID>/jenkins-helm-agent:v0.1

Note: You can also push the image to the OpenShift internal image registry.

Configure pod templates in Jenkins

Next, configure the pod templates for the new Helm agent:

  1. Open the Jenkins console. Click Manage Jenkins —> Manage Nodes and Clouds —> Configure Clouds.
  2. Add new pod templates for the Helm agent and enter helm in the Name and Labels fields, as shown in Figure 3.
Screenshot showing how to add new pod templates for the Helm agent; "helm" has been entered in the Name and Labels fields.
Figure 3: Configuring the Helm agent in the pod template.

Build the Jenkins pipeline stages

Build the pipeline stages:

  1. Add the repo:
    stage("add Repo") {
                        steps {
                               sh "helm repo add shailendra ${repo}"
                            }
                       }

     

  2. Deploy the chart to DEV/UAT:
    stage("Deploy to Dev") {
                            steps {
                                script{
    					openshift.withCluster(){
                                            sh "helm upgrade --install my-guestbook shailendra/guestbook --values dev/values.yaml -n dev --wait"
                                        }
                                    }
                                }
                        }

Sample Jenkinsfile:

def repo="https://shailendra14k.github.io/sample-helm-chart/"
pipeline{
		agent{
			label 'helm'
		}
		stages{
				
                stage("add Repo") {
                        steps {
                               sh "helm repo add shailendra ${repo}"
                            }
                    }
				stage("Deploy to Dev") {
                        steps {
                            script{
					openshift.withCluster(){
                                        sh "helm upgrade --install helm-app shailendra/sample-app --values dev/values.yaml -n dev --wait"
                                    }
                                }
                            }
                    }
                stage("Deploy to UAT") {
                        steps {
                            script{
					openshift.withCluster(){
                                        sh "helm upgrade --install helm-app shailendra/sample-app --values uat/values.yaml -n uat --wait"
                                    }
                                }
                            }
                    }
            }
        }

Deploy the pipeline

Now, you can deploy the pipeline:

  1. Open the Jenkins console and click New Item.
  2. Enter the name and select Pipeline.
  3. Go to the Pipeline tab.
  4. Select Pipeline script from SCM and provide the GitHub link that points to the Jenkinsfile: https://github.com/shailendra14k/sample-helm-chart.git. See Figure 4.
Screenshot showing the Pipeline tab. Select Pipeline script from SCM is selected and the GitHub link that points to the Jenkinsfile is specified.
Figure 4: Adding the GitHub link to the Jenkinsfile in the Pipeline tab.

Run and verify the pipeline

Finally, run and verify the pipeline:

  1. Run the pipeline by clicking Build Now (see Figure 5) and then verify the output.
    Screenshot of the Jenkins console described in this section.
    Figure 5: Running the pipeline.
  2. Verify application deployment on the DEV namespace:
    oc get all -n dev
    NAME                                       READY   STATUS    RESTARTS   AGE
    pod/helm-app-sample-app-7b6bd8f757-bqzq7   1/1     Running   0          92s
    
    NAME                          TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE
    service/helm-app-sample-app   ClusterIP   172.30.20.99           6379/TCP   92s
    
    NAME                                  READY   UP-TO-DATE   AVAILABLE   AGE
    deployment.apps/helm-app-sample-app   1/1     1            1           92s
    
    NAME                                             DESIRED   CURRENT   READY   AGE
    replicaset.apps/helm-app-sample-app-7b6bd8f757   1         1         1       93s
  3. Review the Helm chart status:
    helm list -A
    NAME    	NAMESPACE	REVISION	UPDATED                                	STATUS  	CHART           	APP VERSION
    helm-app    	dev      	2       	2021-02-21 19:40:41.251103914 +0000 UTC	deployed	sample-app-0.1.0	1.16.0
    helm-app    	uat      	2       	2021-02-21 19:40:47.85977876 +0000 UTC 	deployed	sample-app-0.1.0	1.16.0

Conclusion

Thanks for reading! I hope this article helps you get started with Helm CI/CD on OpenShift.