Docker images को optimize करने में size कम करना (smaller, faster, more secure) और build performance बेहतर बनाना (caching के माध्यम से faster builds) शामिल है। techniques में minimal base images, multi-stage builds, layer optimization, BuildKit और careful Dockerfile design शामिल हैं।
image size कम करना
✓ MINIMAL base images:
- alpine (tiny, ~5MB) — but musl libc can cause compatibility issues for some apps
- slim variants (e.g. python:3.12-slim) — smaller than full, fewer compat issues
- DISTROLESS — only the app + runtime, NO shell/package manager (smallest, most secure)
- scratch — empty base (for static binaries, e.g. Go) → minimal image
✓ MULTI-STAGE builds — build with tools, ship only the artifact (huge size savings)
✓ Combine RUN layers + clean up IN the same layer:
RUN apt-get update && apt-get install -y x && rm -rf /var/lib/apt/lists/*
(cleanup in a SEPARATE layer doesn't shrink the image — the files are in the earlier layer)
✓ .dockerignore — keep junk out of the context/image
✓ Remove caches, temp files, dev dependencies in production images
