Docker Basics

Overview

Use this skill to ensure containerized workloads are reproducible, debuggable, and operationally safe.

Scope Boundaries

• Use this skill when the task matches the trigger condition described in description.
• Do not use this skill when the primary task falls outside this skill’s domain.

Shared References

• Runtime risk catalog:
  • references/docker-runtime-risk-catalog.md

Templates And Assets

• Runtime contract template:
  • assets/container-runtime-contract-template.md
• Runtime checklist:
  • assets/docker-runtime-checklist.md

Inputs To Gather

• Application runtime requirements and dependencies.
• Local/dev/prod run differences.
• Required network ports, volumes, and environment variables.
• Security constraints (user, capabilities, filesystem access).

Deliverables

• Container run policy (entrypoint, env, ports, volumes, user).
• Local reproducibility checklist.
• Runtime risk list (permissions, secrets, mutable state).
• Verification steps for startup and health checks.

Quick Example

• Run as non-root user.
• Mount only required volume paths.
• Fail fast if required env vars are missing.
• Expose health endpoint and readiness check.

Quality Standard

• Runtime config is minimal and explicit.
• Container behavior is reproducible across environments.
• Security posture follows least-privilege defaults.
• Health and failure signals are observable.

Workflow

1. Define container runtime contract using assets/container-runtime-contract-template.md.
2. Configure networking, storage, and environment boundaries.
3. Validate startup/health behavior.
4. Verify security constraints and secret handling using assets/docker-runtime-checklist.md.
5. Document reproducible run commands.

Failure Conditions

• Stop when required runtime dependencies are implicit.
• Stop when container requires unnecessary privileged execution.
• Escalate when runtime differences make behavior non-reproducible.