CI/CD and GitOps in Kubernetes

Continuous Integration (CI) and Continuous Deployment (CD) are critical for modern DevOps workflows. Kubernetes (K8s) integrates well with CI/CD pipelines, allowing automated application deployments. GitOps takes this further by using Git as the single source of truth for Kubernetes infrastructure and application configurations.

This article covers:

• Helm and Kustomize for managing Kubernetes configurations.
• ArgoCD and FluxCD for GitOps-based deployments.
• Jenkins, Tekton, and GitHub Actions for automating CI/CD pipelines.

1. Helm - The Kubernetes Package Manager

Helm simplifies Kubernetes application deployment using charts (predefined YAML templates). It provides:

• Version control for Kubernetes applications.
• Reusable application configurations.
• Easy rollbacks.

Installing Helm

curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

Example: Deploying an Nginx Chart

helm repo add bitnami https://charts.bitnami.com/bitnami
helm install my-nginx bitnami/nginx

This command deploys an Nginx instance in Kubernetes.

Helm Values File (Override Defaults)

Modify default configurations using a values.yaml file:

replicaCount: 3
image:
  repository: nginx
  tag: latest
service:
  type: LoadBalancer

Then apply:

helm upgrade --install my-nginx bitnami/nginx -f values.yaml

2. Kustomize - Managing Kubernetes Configurations

Kustomize allows managing Kubernetes configurations without modifying the original YAML files. It enables:

• Overlays for different environments (dev, staging, prod).
• YAML modifications without duplication.
• Patch management.

Example: Kustomization for Different Environments

# kustomization.yaml
resources:
  - deployment.yaml
  - service.yaml

images:
  - name: my-app
    newTag: v2.0

patchesStrategicMerge:
  - deployment-patch.yaml

To apply:

kubectl apply -k .

3. GitOps - ArgoCD and FluxCD

GitOps enables declarative infrastructure management using Git repositories. ArgoCD and FluxCD are popular tools that sync Git changes to Kubernetes.

ArgoCD - Declarative Continuous Deployment

ArgoCD continuously syncs Kubernetes clusters with Git repositories.

Installing ArgoCD

kubectl create namespace argocd
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

Deploying an Application with ArgoCD

argocd app create my-app \
  --repo https://github.com/user/repo.git \
  --path k8s \
  --dest-server https://kubernetes.default.svc \
  --dest-namespace default

ArgoCD monitors the repository and applies changes automatically.

FluxCD - GitOps for Kubernetes

FluxCD is another GitOps tool that automatically deploys Kubernetes manifests from Git.

Installing FluxCD

flux bootstrap github \
  --owner=my-user \
  --repository=my-repo \
  --branch=main \
  --path=clusters/my-cluster

FluxCD watches the repository and syncs updates to the cluster.

4. CI/CD Pipelines for Kubernetes

Jenkins for Kubernetes CI/CD

Jenkins is a popular CI/CD tool with Kubernetes support.

Example: Jenkins Pipeline for Kubernetes Deployment

pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                sh 'docker build -t my-app:v1 .'
            }
        }
        stage('Push') {
            steps {
                sh 'docker push my-registry/my-app:v1'
            }
        }
        stage('Deploy') {
            steps {
                sh 'kubectl apply -f k8s/deployment.yaml'
            }
        }
    }
}

Tekton - Kubernetes-Native CI/CD

Tekton is a cloud-native CI/CD system built for Kubernetes.

Example: Tekton Pipeline

apiVersion: tekton.dev/v1beta1
kind: Pipeline
metadata:
  name: deploy-pipeline
spec:
  tasks:
    - name: build
      taskRef:
        name: build-task
    - name: deploy
      taskRef:
        name: deploy-task
      runAfter:
        - build

Tekton Pipelines run inside Kubernetes for better integration.

GitHub Actions for Kubernetes CI/CD

GitHub Actions enables CI/CD workflows using YAML files.

Example: Deploy to Kubernetes with GitHub Actions

name: Deploy to Kubernetes
on:
  push:
    branches:
      - main
jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v2
      - name: Set up kubectl
        uses: azure/setup-kubectl@v1
      - name: Apply Kubernetes manifests
        run: kubectl apply -f k8s/

5. Best Practices for Kubernetes CI/CD and GitOps

• Use Helm or Kustomize for managing configurations efficiently.
• Adopt GitOps (ArgoCD or FluxCD) for declarative deployments.
• Automate CI/CD pipelines with Jenkins, Tekton, or GitHub Actions.
• Ensure security by restricting access to secrets and Kubernetes clusters.
• Monitor deployments using Prometheus, Grafana, or Kubernetes Events.

CI/CD and GitOps streamline Kubernetes deployments by automating builds, testing, and releases.

• Use Helm or Kustomize to manage configurations.
• Adopt GitOps with ArgoCD or FluxCD for automated deployments.
• Set up CI/CD pipelines with Jenkins, Tekton, or GitHub Actions.

By following these best practices, teams can deploy faster, improve reliability, and maintain Kubernetes clusters efficiently.