Implementing CI/CD for Kubernetes

variables:
  KUBE_CONFIG: "${CI_PROJECT_DIR}/kubeconfig"
  KUBE_NAMESPACE: "default"

before_script:
  - mkdir -p ~/.kube
  - echo "${KUBE_CONFIG_DATA}" | base64 -d > ~/.kube/config
  - export KUBECONFIG=~/.kube/config
  - kubectl config set-context --current --namespace=$KUBE_NAMESPACE

test:
  script:
    - kubectl get nodes

stages:
  - build
  - test

build_job:
  stage: build
  image: alpine:latest
  executor: kubernetes
  kubernetes:
    namespace: production
    resources:
      requests:
        cpu: 100m
        memory: 128Mi
      limits:
        cpu: 200m
        memory: 256Mi
  script:
    - echo "Building the application..."

kubectl apply -f deployment.yaml

kubectl set image deployment/my-app web-server=nginx:1.21

kubectl rollout status deployment/my-app

deploy:
  stage: deploy
  script:
    - helm repo add stable https://charts.helm.sh/stable
    - helm upgrade --install myapp ./charts/myapp \
        --namespace production \
        --values values/prod.yaml
  environment:
    name: production

agent:
  kubernetes:
    namespace: "gitlab-agent"
    image: "gitlab/gitlab-agent:latest"
    serviceAccountName: "gitlab-agent-sa"
    resources:
      requests:
        cpu: "100m"
        memory: "128Mi"
      limits:
        cpu: "200m"
        memory: "256Mi"

stages:
  - build
  - test
  - deploy

build_job:
  stage: build
  script:
    - echo "Building application..."
  artifacts:
    paths:
      - dist/

test_job:
  stage: test
  script:
    - echo "Running tests..."
  environment:
    name: review/$CI_COMMIT_REF_NAME
    url: https://review-$CI_COMMIT_REF_NAME.$EXTERNAL_URL

deploy_job:
  stage: deploy
  script:
    - echo "Deploying to Kubernetes..."
    - kubectl apply -f k8s/deployment.yaml
  environment:
    name: review/$CI_COMMIT_REF_NAME
    url: https://review-$CI_COMMIT_REF_NAME.$EXTERNAL_URL
    on_stop: stop_review
  only:
    - branches

include:
  template: Auto-DevOps.gitlab-ci.yml

auto_devops_enabled: true
auto_devops_artifacts_expiration: 30d

deploy:
  stage: deploy
  script:
    - echo "Deploying to Kubernetes cluster"
    - kubectl set image deployment/my-app my-app=registry.gitlab.com/project/image:latest
  environment:
    name: production
    url: https://myapp.example.com

deploy:
  stage: deploy
  script:
    - echo "Deploying with Kustomize"
    - kustomize build kustomize/ | kubectl apply -f -
  environment:
    name: production

deploy:
  stage: deploy
  script:
    - |
      kubectl create namespace $NAMESPACE_NAME --dry-run=client -o yaml | kubectl apply -f -
    - |
      kubectl label namespace $NAMESPACE_NAME environment=production
  variables:
    NAMESPACE_NAME: production

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: my-app
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://gitlab.com/my-group/my-repo.git
    targetRevision: HEAD
    path: k8s/deployment.yaml
  destination:
    server: https://kubernetes.default.svc
    namespace: production
  syncPolicy:
    automated:
      prune: true
      selfHeal: true