ArgoCD need work with Jenkins or other cicd tool - unix1998/technical_notes GitHub Wiki

Here's how the complete CI/CD pipeline would look:

Complete CI/CD Pipeline:

1. Continuous Integration (CI) Process:

   • Code Changes and Commit:

     • You make changes to your Java code and commit them to the GitHub repository.

   • CI Tool (e.g., Jenkins, GitLab CI, GitHub Actions):

     • The CI tool detects the code changes and starts the build process.
     • The application is built (e.g., using Maven or Gradle for a Java Spring Boot application).
     • The built artifact (e.g., a JAR or WAR file) is used to create a Docker image.
     • The Docker image is tagged (often using a unique identifier such as the Git commit SHA or a version number).
     • The Docker image is pushed to a container registry (e.g., Docker Hub, AWS ECR, Google Container Registry).

2. Continuous Delivery (CD) Process:

   • Argo CD Setup:

     • Argo CD is configured with a Git repository that contains Kubernetes manifests or Helm charts defining your application's deployment configuration.
     • These manifests specify the Docker image to use for the application.

   • GitOps Workflow with Argo CD:

     • The CI tool updates the Kubernetes manifest or Helm chart with the new Docker image tag after the image is pushed to the registry.
     • This updated manifest is committed to the Git repository.

   • Argo CD Auto-Sync:

     • Argo CD, configured to monitor the Git repository, detects the changes to the manifest.
     • Argo CD automatically syncs the cluster state with the desired state defined in the updated manifest.
     • The application in the Kubernetes cluster is redeployed using the new Docker image.

Detailed Step-by-Step Process:

1. Install Argo CD on OpenShift/Kubernetes:

   • Follow the official installation guide to install Argo CD on your cluster.

2. Set Up CI Tool (e.g., Jenkins):

   • Jenkins Pipeline Example:

     pipeline {
       agent any
       stages {
         stage('Checkout') {
           steps {
             git 'https://github.com/my-org/my-java-app-repo'
           }
         }
         stage('Build') {
           steps {
             sh 'mvn clean package'
           }
         }
         stage('Build Docker Image') {
           steps {
             script {
               def commitHash = sh(script: 'git rev-parse --short HEAD', returnStdout: true).trim()
               docker.build("myregistry/myapp:${commitHash}")
             }
           }
         }
         stage('Push Docker Image') {
           steps {
             script {
               docker.withRegistry('https://myregistry', 'registry-credentials') {
                 def commitHash = sh(script: 'git rev-parse --short HEAD', returnStdout: true).trim()
                 docker.image("myregistry/myapp:${commitHash}").push()
               }
             }
           }
         }
         stage('Update Kubernetes Manifests') {
           steps {
             script {
               def commitHash = sh(script: 'git rev-parse --short HEAD', returnStdout: true).trim()
               sh "sed -i 's|image: myregistry/myapp:.*|image: myregistry/myapp:${commitHash}|' k8s-manifests/deployment.yaml"
               sh 'git add k8s-manifests/deployment.yaml'
               sh 'git commit -m "Update deployment with image myregistry/myapp:${commitHash}"'
               sh 'git push'
             }
           }
         }
       }
     }
     

3. Create Argo CD Application:

   • Use the Argo CD UI or CLI to create an application specifying the Git repository and the path where your Kubernetes manifests are stored.

   apiVersion: argoproj.io/v1alpha1
   kind: Application
   metadata:
     name: my-java-app
     namespace: argocd
   spec:
     project: default
     source:
       repoURL: 'https://github.com/my-org/my-java-app-repo'
       targetRevision: HEAD
       path: 'k8s-manifests'
     destination:
       server: 'https://kubernetes.default.svc'
       namespace: my-app-namespace
     syncPolicy:
       automated:
         prune: true
         selfHeal: true
   

4. Enable Auto-Sync in Argo CD:

   • Ensure that the syncPolicy in your Argo CD Application manifest is set to automated with prune and selfHeal enabled to ensure automatic synchronization and self-healing.

Summary:

• Jenkins (or another CI tool) handles the build, test, and Docker image creation.
• Argo CD manages the deployment of the application in the Kubernetes/OpenShift cluster by monitoring the Git repository for changes to the Kubernetes manifests.
• When the Java code changes and is committed to GitHub, Jenkins builds a new Docker image and pushes it to the registry. Jenkins then updates the Kubernetes manifest with the new image tag and commits this change to the Git repository.
• Argo CD detects this change and redeploys the application using the new Docker image.

In this way, Jenkins and Argo CD work together to achieve a complete CI/CD pipeline.