= Docker BuildKit =

'''Build``Kit''' is the abstracted and improved version of the container image builder that is (''used to be?'') shipped with `docker(8)`.

<<TableOfContents>>

----



== Installation ==

In vertsion 23, the legacy builder for Docker images was deprecated. The deprecation message is as follows:

{{{
DEPRECATED: The legacy builder is deprecated and will be removed in a future release.
            Install the buildx component to build images with BuildKit:
            https://docs.docker.com/go/buildx/
}}}

Build``Kit (also known as '''buildx''') is now the only supported builder. Users must opt in by setting `DOCKER_BUILDKIT=1`. Removal of the legacy builder has not yet been scheduled.

Users may also need to install the `buildx` plugin separately. This error would appear as:

{{{
ERROR: BuildKit is enabled but the buildx component is missing or broken.
       Install the buildx component to build images with BuildKit:
       https://docs.docker.com/go/buildx/
}}}

On [[Linux/Arch|Arch]], install `docker-buildx`.

----



== Usage ==

{{{
docker build .
}}}



=== Contexts ===

Build``Kit supports building in an isolated context (i.e., inside a container). Try:

{{{
$ docker buildx create --name my-builder --driver docker-container --bootstrap --use
$ docker buildx ls
NAME/NODE         DRIVER/ENDPOINT                   STATUS    BUILDKIT   PLATFORMS
my-builder*       docker-container                                       
 \_ my-builder0    \_ unix:///var/run/docker.sock   running   v0.25.1    linux/amd64 (+3), linux/arm64, linux/arm (+2), linux/ppc64le, (7 more)
default           docker                                                 
 \_ default        \_ default                       running   v0.25.1    linux/amd64 (+3), linux/arm64, linux/arm (+2), linux/ppc64le, (7 more)
}}}

One important advantage to this system is building multi-platform images.

{{{
docker buildx build --platform=linux/amd64,linux/arm64 .
}}}



----
CategoryRicottone