docker-slim

View documentation for the original command

$ tldr slim

docker-slim [global-options] <command> [options] [args]
Common: docker-slim build [--target <image[:tag]>] [--http-probe] [options]

--debug
    Enable debug logging

--verbose
    Verbose output

--log-level
    Set log level (debug,info,warn,error)

--target
    Target image to slim (required for build)

--http-probe
    Use HTTP probe to detect app readiness (default: auto)

--http-probe-port
    HTTP probe port (default: 8080)

--http-probe-path
    HTTP probe path (default: /)

--exec
    Custom exec command instead of HTTP probe

--cmd
    Override CMD in profiled container

--entrypoint
    Override ENTRYPOINT

--env
    Add environment variables (repeatable)

--include-path
    Always include paths (repeatable)

--exclude-path
    Exclude paths (repeatable)

--preserve-paths
    Preserve specific paths

--dry-run
    Dry run without building

--continue-after
    Continue after probe success (seconds)

DockerSlim (docker-slim) is an open-source CLI tool that automatically generates slimmer production-ready Docker images. It uses dynamic instrumentation to profile a running container: launches a modified version of the image, monitors filesystem accesses, binary executions, network interactions, and runtime behavior.

The process captures only what's actually used by the application (e.g., specific libraries, files), then creates a new minimal Dockerfile and builds a optimized image. Typical reductions: 30-90% smaller sizes, improving security (smaller attack surface) and deployment speed.

Key features: HTTP health probes for web apps, custom exec commands for others, static xray analysis, Dockerfile linting. Works with most images; best for static-ish apps. Requires Docker daemon. Main workflow: docker-slim build myapp. Supports advanced configs like env vars, path includes/excludes.

Requires Docker daemon; may miss dynamically loaded content; not for images needing full runtime env; experimental for complex apps; increases build time initially.

build: Main slimming; xray: Static image scan; lint: Dockerfile checker; profile: Container profiling.

curl -L https://downloads.docksal.io/docker-slim/channels/latest/docker-slim-linux.tar.gz | tar -xzC /usr/local/bin
Or: brew install docker-slim/tap/docker-slim

Developed by dslim-dev starting 2016; v1.36+ (2022+) adds BuildKit support, better ARM; actively maintained on GitHub with 10k+ stars; evolved from static to dynamic analysis focus.

docker(1), podman(1), buildah(1)