Agent-almanac setup-container-registry
git clone https://github.com/pjt222/agent-almanac
T=$(mktemp -d) && git clone --depth=1 https://github.com/pjt222/agent-almanac "$T" && mkdir -p ~/.claude/skills && cp -r "$T/i18n/caveman/skills/setup-container-registry" ~/.claude/skills/pjt222-agent-almanac-setup-container-registry-b71a0a && rm -rf "$T"
i18n/caveman/skills/setup-container-registry/SKILL.mdSetup Container Registry
Configure production-ready container registries with security scanning, access control, and automated CI/CD integration.
When to Use
- Setting up private container registry for organization
- Migrating from Docker Hub to self-hosted or alternative registries
- Implementing image vulnerability scanning in CI/CD pipelines
- Managing multi-architecture images (amd64, arm64) with manifests
- Enforcing image signing and provenance verification
- Configuring automatic image cleanup and retention policies
Inputs
- Required: Docker or Podman installed locally
- Required: Registry credentials (personal access tokens, service accounts)
- Optional: Self-hosted infrastructure for Harbor deployment
- Optional: Kubernetes cluster for registry integration
- Optional: Cosign/Notary for image signing
- Optional: Trivy or Clair for vulnerability scanning
Procedure
See Extended Examples for complete configuration files and templates.
Step 1: Configure GitHub Container Registry (ghcr.io)
Set up GitHub Container Registry with personal access tokens and CI/CD integration.
# Create GitHub Personal Access Token # Go to: Settings → Developer settings → Personal access tokens → Tokens (classic) # Required scopes: write:packages, read:packages, delete:packages # Login to ghcr.io echo $GITHUB_TOKEN | docker login ghcr.io -u USERNAME --password-stdin # Verify login docker info | grep -A 5 "Registry:" # Tag image for ghcr.io docker tag myapp:latest ghcr.io/USERNAME/myapp:latest docker tag myapp:latest ghcr.io/USERNAME/myapp:v1.0.0 # Push image docker push ghcr.io/USERNAME/myapp:latest docker push ghcr.io/USERNAME/myapp:v1.0.0 # Configure in GitHub Actions cat > .github/workflows/docker-build.yml <<'EOF' name: Build and Push Docker Image locale: caveman source_locale: en source_commit: 82c77053 translator: "Julius Brussee homage — caveman" translation_date: "2026-04-19" on: push: branches: [main] tags: ['v*'] env: REGISTRY: ghcr.io IMAGE_NAME: ${{ github.repository }} jobs: build-and-push: runs-on: ubuntu-latest permissions: contents: read packages: write steps: - name: Checkout code uses: actions/checkout@v4 - name: Set up Docker Buildx uses: docker/setup-buildx-action@v3 - name: Log in to GitHub Container Registry 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=ref,event=branch type=ref,event=pr type=semver,pattern={{version}} type=semver,pattern={{major}}.{{minor}} type=sha,prefix={{branch}}- - name: Build and push uses: docker/build-push-action@v5 with: context: . platforms: linux/amd64,linux/arm64 push: true tags: ${{ steps.meta.outputs.tags }} labels: ${{ steps.meta.outputs.labels }} cache-from: type=gha cache-to: type=gha,mode=max EOF # Make package public (default is private) # Go to: github.com/USERNAME?tab=packages → Select package → Package settings → Change visibility # Pull image (public packages don't require authentication) docker pull ghcr.io/USERNAME/myapp:latest
Expected: GitHub token has package permissions. Docker login succeeds. Images push to ghcr.io with proper tagging. GitHub Actions workflow builds multi-architecture images with automated tagging. Package visibility configured correctly.
On failure: For authentication errors, verify token has
write:packages scope and hasn't expired. For push failures, check repository name matches image name (case-sensitive). For workflow failures, verify permissions: packages: write is set. For public packages not accessible, wait up to 10 minutes for visibility change to propagate.
Step 2: Configure Docker Hub with Automated Builds
Set up Docker Hub repository with access tokens and vulnerability scanning.
# Create Docker Hub access token # Go to: hub.docker.com → Account Settings → Security → New Access Token # Login to Docker Hub echo $DOCKERHUB_TOKEN | docker login -u USERNAME --password-stdin # Create repository # Go to: hub.docker.com → Repositories → Create Repository # Select: public or private, enable vulnerability scanning (Pro/Team plan) # Tag for Docker Hub docker tag myapp:latest USERNAME/myapp:latest docker tag myapp:latest USERNAME/myapp:v1.0.0 # Push to Docker Hub docker push USERNAME/myapp:latest docker push USERNAME/myapp:v1.0.0 # Configure automated builds (legacy feature, deprecated) # Modern approach: Use GitHub Actions with Docker Hub cat > .github/workflows/dockerhub.yml <<'EOF' name: Docker Hub Push locale: caveman source_locale: en source_commit: 82c77053 translator: "Julius Brussee homage — caveman" translation_date: "2026-04-19" on: push: branches: [main] tags: ['v*'] jobs: build: runs-on: ubuntu-latest steps: - uses: actions/checkout@v4 - name: Set up QEMU uses: docker/setup-qemu-action@v3 - name: Set up Docker Buildx uses: docker/setup-buildx-action@v3 - name: Login to Docker Hub uses: docker/login-action@v3 with: username: ${{ secrets.DOCKERHUB_USERNAME }} password: ${{ secrets.DOCKERHUB_TOKEN }} - name: Build and push uses: docker/build-push-action@v5 with: context: . platforms: linux/amd64,linux/arm64,linux/arm/v7 push: true tags: | ${{ secrets.DOCKERHUB_USERNAME }}/myapp:latest ${{ secrets.DOCKERHUB_USERNAME }}/myapp:${{ github.ref_name }} build-args: | BUILD_DATE=$(date -u +'%Y-%m-%dT%H:%M:%SZ') VCS_REF=${{ github.sha }} - name: Update Docker Hub description uses: peter-evans/dockerhub-description@v3 with: username: ${{ secrets.DOCKERHUB_USERNAME }} password: ${{ secrets.DOCKERHUB_TOKEN }} repository: ${{ secrets.DOCKERHUB_USERNAME }}/myapp readme-filepath: ./README.md EOF # View vulnerability scan results # Go to: hub.docker.com → Repository → Tags → View scan results # Configure webhook for automated triggers # Go to: Repository → Webhooks → Add webhook WEBHOOK_URL="https://example.com/webhook" curl -X POST https://hub.docker.com/api/content/v1/repositories/USERNAME/myapp/webhooks \ -H "Authorization: Bearer $DOCKERHUB_TOKEN" \ -H "Content-Type: application/json" \ -d "{\"name\":\"CI Trigger\",\"webhook_url\":\"$WEBHOOK_URL\"}"
Expected: Docker Hub access token created with read/write permissions. Images push successfully with multi-architecture support. Vulnerability scans run automatically (if enabled). README syncs from GitHub. Webhooks trigger on image push.
On failure: For rate limit errors, upgrade to Pro plan or implement pull-through cache. For scan failures, verify plan includes scanning (not available on free tier). For multi-arch build failures, ensure QEMU installed with
docker run --privileged --rm tonistiigi/binfmt --install all. For webhook failures, verify endpoint is publicly accessible and returns 200 OK.
Step 3: Deploy Harbor Self-Hosted Registry
Install Harbor with Helm for enterprise registry with RBAC and replication.
# Add Harbor Helm repository helm repo add harbor https://helm.gopharbor.io helm repo update # Create namespace kubectl create namespace harbor # Create values file cat > harbor-values.yaml <<EOF expose: type: ingress tls: enabled: true certSource: secret secret: secretName: harbor-tls ingress: hosts: core: harbor.example.com className: nginx annotations: cert-manager.io/cluster-issuer: letsencrypt-prod externalURL: https://harbor.example.com persistence: enabled: true persistentVolumeClaim: registry: size: 200Gi storageClass: gp3 database: size: 10Gi storageClass: gp3 harborAdminPassword: "ChangeMe123!" database: type: internal # Use external: postgres for production redis: type: internal # Use external: redis for production trivy: enabled: true skipUpdate: false notary: enabled: true # Image signing chartmuseum: enabled: true # Helm chart storage EOF # Install Harbor helm install harbor harbor/harbor \ --namespace harbor \ --values harbor-values.yaml \ --timeout 10m # Wait for pods to be ready kubectl get pods -n harbor -w # Get admin password kubectl get secret -n harbor harbor-core -o jsonpath='{.data.HARBOR_ADMIN_PASSWORD}' | base64 -d # Access Harbor UI echo "Harbor UI: https://harbor.example.com" echo "Username: admin" # Login via Docker CLI docker login harbor.example.com # Username: admin # Password: (from above) # Create project via API curl -u "admin:$HARBOR_PASSWORD" -X POST \ https://harbor.example.com/api/v2.0/projects \ -H "Content-Type: application/json" \ -d '{ "project_name": "myapp", "public": false, "metadata": { "auto_scan": "true", "severity": "high", "enable_content_trust": "true" } }' # Tag and push to Harbor docker tag myapp:latest harbor.example.com/myapp/app:latest docker push harbor.example.com/myapp/app:latest # Configure robot account for CI/CD # UI: Administration → Robot Accounts → New Robot Account # Permissions: Pull, Push to specific projects # Use robot account in CI/CD docker login harbor.example.com -u 'robot$myapp-ci' -p "$ROBOT_TOKEN"
Expected: Harbor deploys to Kubernetes with PostgreSQL and Redis. Ingress configured with TLS. Admin UI accessible. Projects created with vulnerability scanning enabled. Robot accounts provide CI/CD authentication. Trivy scans images on push.
On failure: For database connection errors, check PostgreSQL pod logs with
kubectl logs -n harbor harbor-database-0. For Ingress issues, verify DNS points to LoadBalancer and cert-manager issued certificate. For Trivy failures, check if vulnerability database downloaded successfully. For storage issues, verify PVCs bound with kubectl get pvc -n harbor.
Step 4: Implement Image Tagging Strategy and Retention Policies
Configure semantic versioning, immutable tags, and automatic cleanup.
# Tagging best practices # 1. Semantic versioning docker tag myapp:latest harbor.example.com/myapp/app:v1.2.3 docker tag myapp:latest harbor.example.com/myapp/app:v1.2 docker tag myapp:latest harbor.example.com/myapp/app:v1 docker tag myapp:latest harbor.example.com/myapp/app:latest # ... (see EXAMPLES.md for complete configuration)
Expected: Images tagged with semantic versions, commit SHAs, and environment labels. Retention policies automatically clean old images based on age, pull activity, or count limits. Production tags (v* pattern) retained longer than development branches. Untagged images deleted to save storage.
On failure: For retention not triggering, verify cron schedule syntax and Harbor timezone settings. For accidental deletion of production images, implement immutable tags with Harbor tag immutability rules. For storage still growing, check artifact retention includes Helm charts and other OCI artifacts. For policy conflicts, ensure retention rules use
or algorithm and don't contradict each other.
Step 5: Configure Kubernetes Image Pull Secrets
Set up registry authentication for Kubernetes clusters.
# Create Docker registry secret kubectl create secret docker-registry ghcr-secret \ --docker-server=ghcr.io \ --docker-username=USERNAME \ --docker-password=$GITHUB_TOKEN \ --docker-email=user@example.com \ # ... (see EXAMPLES.md for complete configuration)
Expected: Image pull secrets created in target namespaces. Pods successfully pull images from private registries. Service accounts include imagePullSecrets. No ImagePullBackOff errors.
On failure: For authentication errors, verify credentials with
docker login manually. For secret not found, check namespace matches Pod namespace. For still failing, decode secret and verify JSON structure with kubectl get secret ghcr-secret -o jsonpath='{.data.\.dockerconfigjson}' | base64 -d | jq. For token expiration, rotate credentials and update secrets.
Step 6: Enable Vulnerability Scanning and Image Signing
Integrate Trivy scanning and Cosign for image provenance.
# Install Trivy CLI wget https://github.com/aquasecurity/trivy/releases/latest/download/trivy_0.47.0_Linux-64bit.tar.gz tar zxvf trivy_0.47.0_Linux-64bit.tar.gz sudo mv trivy /usr/local/bin/ # Scan local image # ... (see EXAMPLES.md for complete configuration)
Expected: Trivy scans detect vulnerabilities with severity ratings. SARIF results upload to GitHub Security tab. Critical vulnerabilities fail CI/CD builds. Cosign signs images with keypair or keyless (Fulcio). Verification succeeds for signed images. Kyverno blocks unsigned images in Kubernetes.
On failure: For Trivy database download failures, run
trivy image --download-db-only. For false positives, create .trivyignore file with CVE IDs and justifications. For Cosign signature failures, verify image digest hasn't changed (signatures apply to specific digest, not tags). For Kyverno policy failures, check image reference pattern matches actual image names. For keyless signing, verify OIDC token has sufficient permissions.
Validation
- Registry accessible via Docker CLI login
- Images push and pull successfully with proper authentication
- Multi-architecture images build and manifest created
- Vulnerability scanning runs automatically on image push
- Retention policies clean old images on schedule
- Kubernetes clusters can pull images via imagePullSecrets
- Image signatures verified before deployment
- Webhook notifications trigger on image updates
- Registry UI shows scan results and artifact metadata
Common Pitfalls
-
Public images by default: GitHub packages are private by default, Docker Hub public. Verify visibility settings match security requirements.
-
Token expiration: Personal access tokens expire, breaking CI/CD. Use non-expiring tokens for automation or implement rotation.
-
Untagged image accumulation: Build process creates untagged images consuming storage. Enable automatic cleanup of untagged artifacts.
-
Missing multi-arch support: Builds only amd64, fails on ARM instances. Use
withdocker buildx
flag for cross-platform builds.--platform -
No rate limit protection: Free Docker Hub accounts limited to 100 pulls/6h. Implement pull-through cache or upgrade plan.
-
Mutable tags:
tag overwritten breaks reproducibility. Use immutable tags (commit SHA, semantic version) for production.latest -
Insecure registry communication: Self-hosted registry without TLS. Always use HTTPS with valid certificates.
-
No access control: Single credential shared across teams. Implement RBAC with project-specific robot accounts.
Related Skills
- Building container images for registrycreate-r-dockerfile
- Efficient image builds for registry pushoptimize-docker-build-cache
- Automated registry push in CI/CDbuild-ci-cd-pipeline
- Pulling images from registrydeploy-to-kubernetes
- Image promotion between registriesimplement-gitops-workflow