docker commit: Create an Image from a Container

Snapshot a container into a new image - handy for debugging, not for builds.

docker commit creates a new image from a container current state. This page covers the flags and why reproducible builds should use a Dockerfile instead.

What it does

docker commit captures the writable layer of a container (changes since it started) as a new image layer, optionally setting config like CMD. Unlike a Dockerfile build, the result is opaque and not reproducible.

Common usage

Terminal

docker commit mycontainer myimage:debug
docker commit -m "added patch" -a "me" mycontainer myimage:patched
docker commit --change "CMD [\"node\",\"server.js\"]" mycontainer myapp:snap

Common errors in CI

commit is fine for capturing a broken container to inspect later, but in CI prefer a Dockerfile: a committed image cannot be rebuilt from source, has no cache benefits, and hides what changed. If the new image "does nothing", you likely did not carry CMD over - set it with --change at commit time.

Related guides

docker build: Usage, Options & Common CI ErrorsHow docker build works: building an image from a Dockerfile, tagging, build args, target stages, and the buil… docker export: Export a Container FilesystemHow docker export works: flattening a container filesystem to a tar, how it differs from docker save, and CI… docker import: Create an Image from a TarballHow docker import works: building a single-layer image from a filesystem tar, setting CMD on import, and the… docker inspect: Low-Level Container & Image DetailHow docker inspect works: dumping JSON metadata for containers, images, volumes, and networks, with --format…