cicd-expert

CI/CD Expert

Expert guidance for Continuous Integration and Continuous Deployment, including GitHub Actions, Jenkins, GitLab CI, deployment strategies, and automation best practices.

Core Concepts

CI/CD Fundamentals

• Continuous Integration (CI)
• Continuous Delivery vs Deployment
• Build automation
• Test automation
• Artifact management
• Deployment strategies (blue-green, canary, rolling)

Pipeline Design

• Pipeline stages and jobs
• Parallel execution
• Dependencies and artifacts
• Caching strategies
• Matrix builds
• Conditional execution

Security

• Secret management
• Dependency scanning
• SAST/DAST
• Container scanning
• Supply chain security
• SBOM generation

GitLab CI

# .gitlab-ci.yml
stages:
  - build
  - test
  - security
  - deploy

variables:
  DOCKER_DRIVER: overlay2
  DOCKER_TLS_CERTDIR: '/certs'
  IMAGE_TAG: $CI_REGISTRY_IMAGE:$CI_COMMIT_SHORT_SHA

default:
  image: node:20-alpine
  cache:
    key: ${CI_COMMIT_REF_SLUG}
    paths:
      - node_modules/
      - .npm/

build:
  stage: build
  script:
    - npm ci --cache .npm --prefer-offline
    - npm run build
  artifacts:
    paths:
      - dist/
    expire_in: 1 week

test:unit:
  stage: test
  needs: [build]
  script:
    - npm ci --cache .npm --prefer-offline
    - npm run test:unit -- --coverage
  coverage: '/All files[^|]*\|[^|]*\s+([\d\.]+)/'
  artifacts:
    reports:
      junit: test-results/unit/*.xml
      coverage_report:
        coverage_format: cobertura
        path: coverage/cobertura-coverage.xml

test:integration:
  stage: test
  needs: [build]
  services:
    - postgres:15
    - redis:7
  variables:
    POSTGRES_DB: testdb
    POSTGRES_USER: testuser
    POSTGRES_PASSWORD: testpass
  script:
    - npm ci --cache .npm --prefer-offline
    - npm run test:integration
  artifacts:
    reports:
      junit: test-results/integration/*.xml

security:sast:
  stage: security
  image: returntocorp/semgrep
  script:
    - semgrep --config=auto --json --output=sast-report.json .
  artifacts:
    reports:
      sast: sast-report.json

security:dependency:
  stage: security
  script:
    - npm audit --audit-level=high
  allow_failure: true

docker:build:
  stage: build
  image: docker:24
  services:
    - docker:24-dind
  before_script:
    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
  script:
    - docker build -t $IMAGE_TAG .
    - docker push $IMAGE_TAG
  only:
    - main
    - tags

deploy:staging:
  stage: deploy
  image: bitnami/kubectl:latest
  environment:
    name: staging
    url: https://staging.example.com
  script:
    - kubectl config use-context $KUBE_CONTEXT_STAGING
    - kubectl set image deployment/web-app web-app=$IMAGE_TAG -n staging
    - kubectl rollout status deployment/web-app -n staging --timeout=5m
  only:
    - main

deploy:production:
  stage: deploy
  image: bitnami/kubectl:latest
  environment:
    name: production
    url: https://example.com
  script:
    - kubectl config use-context $KUBE_CONTEXT_PRODUCTION
    - kubectl set image deployment/web-app web-app=$IMAGE_TAG -n production
    - kubectl rollout status deployment/web-app -n production --timeout=5m
  when: manual
  only:
    - tags

Deployment Strategies

Blue-Green Deployment

# GitHub Actions
- name: Blue-Green Deployment
  run: |
    # Deploy to green environment
    kubectl apply -f k8s/green/
    kubectl rollout status deployment/app-green -n production

    # Run smoke tests
    npm run test:smoke -- --env=green

    # Switch traffic to green
    kubectl patch service app -n production -p '{"spec":{"selector":{"version":"green"}}}'

    # Keep blue for rollback
    echo "Blue environment kept for rollback"

Canary Deployment

# Deploy canary (10% traffic)
- name: Deploy Canary
  run: |
    kubectl apply -f k8s/canary/
    kubectl set image deployment/app-canary app=$IMAGE_TAG -n production

    # Monitor metrics
    sleep 300

    # Check error rate
    ERROR_RATE=$(curl -s "$PROMETHEUS_URL/api/v1/query?query=error_rate" | jq -r '.data.result[0].value[1]')

    if (( $(echo "$ERROR_RATE < 0.01" | bc -l) )); then
      # Promote canary to stable
      kubectl set image deployment/app-stable app=$IMAGE_TAG -n production
      kubectl scale deployment/app-canary --replicas=0 -n production
    else
      # Rollback canary
      kubectl scale deployment/app-canary --replicas=0 -n production
      exit 1
    fi

Rolling Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: app
spec:
  replicas: 10
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 2 # Max 2 pods above desired count
      maxUnavailable: 1 # Max 1 pod unavailable during update
  template:
    spec:
      containers:
        - name: app
          image: myapp:v2
          readinessProbe:
            httpGet:
              path: /health
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 5

Best Practices

Pipeline Design

• Keep pipelines fast (< 10 minutes for CI)
• Fail fast on errors
• Run tests in parallel
• Cache dependencies
• Use matrix builds for multiple versions
• Separate CI and CD pipelines
• Make pipelines idempotent

Security

• Scan dependencies for vulnerabilities
• Scan container images
• Use least privilege for credentials
• Rotate secrets regularly
• Sign commits and artifacts
• Use private registries
• Implement SBOM generation

Artifact Management

• Use semantic versioning
• Tag images with git SHA
• Store artifacts in registries
• Implement retention policies
• Generate build manifests
• Track provenance

Monitoring & Observability

• Track build success rate
• Monitor pipeline duration
• Alert on failures
• Log all deployments
• Track deployment frequency
• Measure lead time and MTTR

Anti-Patterns to Avoid

❌ No automated tests: Deployments without tests are risky ❌ Manual deployments: Automate all deployments ❌ Shared credentials: Use role-based access ❌ No rollback strategy: Always have a rollback plan ❌ Long-running pipelines: Keep pipelines fast ❌ Environment drift: Use IaC for all environments ❌ No monitoring: Track deployment health ❌ Direct production access: Deploy through pipelines only

Reference Documentation

Detailed material lives alongside this skill and is read on demand:

• GitHub Actions — Workflow Basics, Docker Build and Push, Deployment Workflow, Reusable Workflows, Composite Actions
• Jenkins — Declarative Pipeline, Shared Library

Resources

• GitHub Actions: https://docs.github.com/en/actions
• Jenkins: https://www.jenkins.io/doc/
• GitLab CI: https://docs.gitlab.com/ee/ci/
• Argo CD: https://argo-cd.readthedocs.io/
• Tekton: https://tekton.dev/docs/