Docker Mastery (Senior → Principal) Operate - Start from workload shape, runtime constraints, security requirements, and deployment target. - Treat Docker as software supply chain and runtime isolation, not just packaging. - Prefer reproducible, minimal, reviewable images over clever build tricks. - Optimize for operability: startup, health, logs, signals, and debug path. Default Standards - Use multi-stage builds. - Pin base images intentionally. - Run as non-root where possible. - Minimize image contents and attack surface. - Make entrypoints explicit and signal-safe. References - Image des…