| name | ops-docker |
| description | Docker and Docker Compose containerization. Trigger when the user wants to dockerize an application or create containers. |
| allowed-tools | ["Read","Write","Edit","Bash","Glob","Grep"] |
| context | fork |
| disable-model-invocation | true |
Docker Containerization (pointer)
Dockerfile syntax, Compose schema and image-publish flows drift on each release and are canonical at:
Foundation discipline (keep across releases)
- Multi-stage builds: always separate build deps from runtime image. The "node:20 with full npm" image weighs 1GB+; the runtime layer should be ~100MB. Build stage produces artifacts, runtime stage copies them in.
- Non-root user:
RUN addgroup -S app && adduser -S app -G app && USER app — never run app code as root inside the container, even if "it's just a sandbox".
- .dockerignore mandatory: forgotten
.git/ or node_modules/ in the build context bloats images by hundreds of MB and leaks secrets. The .dockerignore rules mirror your .gitignore plus build artifacts.
- HEALTHCHECK at the Dockerfile level: not just at the orchestrator level. Lets Docker/Compose detect unhealthy containers before the orchestrator does.
- Pin base image major+minor (
node:20-alpine, not node:latest or bare node:20): floating tags break reproducibility; SHA pinning is overkill for most apps but worth it for security-critical builds.
- Secret management: never
COPY .env or hardcode credentials in ENV. Use BuildKit secrets (--mount=type=secret) or runtime-injected env vars from the orchestrator.
See also
/ops:ops-deploy — deployment checklist consumes the built image/ops:ops-database — Compose patterns for DB services (depends_on: { condition: service_healthy })qa-security — image scanning gate (Snyk/Trivy) before pushops-ci — Hadolint + image scan as CI steps
