Docker CI/CD Skill

Integrate Docker with CI/CD pipelines for automated image builds, security scanning, and deployments.

Purpose

Set up automated Docker workflows with GitHub Actions, GitLab CI, and other CI/CD platforms.

Parameters

GitHub Actions

Complete Workflow

name: Docker Build and Deploy

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  build:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

    steps:
      - uses: actions/checkout@v4

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Login to Registry
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=sha
            type=ref,event=branch
            type=semver,pattern={{version}}

      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          context: .
          push: ${{ github.event_name != 'pull_request' }}
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

      - name: Scan for vulnerabilities
        uses: aquasecurity/trivy-action@master
        with:
          image-ref: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:sha-${{ github.sha }}
          exit-code: '1'
          severity: 'CRITICAL,HIGH'

Multi-Arch Build

- name: Set up QEMU
  uses: docker/setup-qemu-action@v3

- name: Build multi-arch
  uses: docker/build-push-action@v5
  with:
    platforms: linux/amd64,linux/arm64
    push: true
    tags: ${{ steps.meta.outputs.tags }}

GitLab CI

# .gitlab-ci.yml
stages:
  - build
  - scan
  - deploy

variables:
  DOCKER_IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA

build:
  stage: build
  image: docker:24
  services:
    - docker:24-dind
  script:
    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
    - docker build -t $DOCKER_IMAGE .
    - docker push $DOCKER_IMAGE

scan:
  stage: scan
  image:
    name: aquasec/trivy
    entrypoint: [""]
  script:
    - trivy image --exit-code 1 --severity CRITICAL $DOCKER_IMAGE

deploy:
  stage: deploy
  script:
    - ssh deploy@server "docker pull $DOCKER_IMAGE && docker compose up -d"
  only:
    - main

Best Practices

Caching

# GitHub Actions BuildKit cache
cache-from: type=gha
cache-to: type=gha,mode=max

# GitLab cache
cache:
  key: docker-$CI_COMMIT_REF_SLUG
  paths:
    - .docker-cache

Security

# Scan before push
- name: Scan
  run: trivy image --exit-code 1 --severity CRITICAL $IMAGE

# Sign images (cosign)
- name: Sign
  run: cosign sign $IMAGE

Error Handling

Common Errors

unauthorized

rate limit

cache miss

Fallback Strategy

1. Build without cache if cache corrupted
2. Use fallback registry if primary down
3. Deploy previous version on failure

Troubleshooting

Debug Checklist

• Registry credentials valid?
• Docker daemon running?
• Build context correct?
• Dockerfile present?

Usage

Skill("docker-ci-cd")

Assets

• assets/github-actions-docker.yaml

  - GitHub Actions template

• scripts/build-and-push.sh

  - Build script

Related Skills

• docker-production
• docker-security