availability confusion

[tcurdt]

I am trying to get buildx builds working in gitlab. From the documentation it sounds like this should already be available but I see the following:

stages:
  - build

build:
  stage: build
  image: docker:latest
  services:
  - docker:dind
  script:
  - docker version
  - DOCKER_CLI_EXPERIMENTAL=enabled docker buildx --help

Using docker image sha256:3052dea93a5a9ecba2e2c33d4ee11f0d5813f767dff6763e06ddfd4d2ad836c4 for docker:dind with digest docker@sha256:5f7534177e58946bfffd730e57c4999fc50b231d2b3ee4dc92dcb84f5f43582a ...
...
Using docker image sha256:ebd66f099af1dc76feb71dacb013f9feef9f3fa8033979b91061bdd94649d2fe for docker:latest with digest docker@sha256:7913d273f368a0c80cee682e45fc66ff8cd3900ac956afa6e0f68c2b0bbc0a02 ...
Preparing environment
...
Using docker image sha256:ebd66f099af1dc76feb71dacb013f9feef9f3fa8033979b91061bdd94649d2fe for docker:latest with digest docker@sha256:7913d273f368a0c80cee682e45fc66ff8cd3900ac956afa6e0f68c2b0bbc0a02 ...
...
$ docker version
Client: Docker Engine - Community
 Version:           20.10.3
 API version:       1.41
 Go version:        go1.13.15
 Git commit:        48d30b5
 Built:             Fri Jan 29 14:28:23 2021
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true
Server: Docker Engine - Community
 Engine:
  Version:          20.10.3
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.13.15
  Git commit:       46229ca
  Built:            Fri Jan 29 14:31:57 2021
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          v1.4.3
  GitCommit:        269548fa27e0089a8b8278fc4fc781d7f65a939b
 runc:
  Version:          1.0.0-rc92
  GitCommit:        ff819c7e9184c13b7c2607fe6c30ae19403a7aff
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0
$ DOCKER_CLI_EXPERIMENTAL=enabled docker buildx --help
Usage:  docker [OPTIONS] COMMAND
A self-sufficient runtime for containers
Options:
      --config string      Location of client config files (default
                           "/root/.docker")
  -c, --context string     Name of the context to use to connect to the
                           daemon (overrides DOCKER_HOST env var and
                           default context set with "docker context use")
  -D, --debug              Enable debug mode
  -H, --host list          Daemon socket(s) to connect to
  -l, --log-level string   Set the logging level
                           ("debug"|"info"|"warn"|"error"|"fatal")
                           (default "info")
      --tls                Use TLS; implied by --tlsverify
      --tlscacert string   Trust certs signed only by this CA (default
                           "/root/.docker/ca.pem")
      --tlscert string     Path to TLS certificate file (default
                           "/root/.docker/cert.pem")
      --tlskey string      Path to TLS key file (default
                           "/root/.docker/key.pem")
      --tlsverify          Use TLS and verify the remote
  -v, --version            Print version information and quit
Management Commands:
  builder     Manage builds
  config      Manage Docker configs
  container   Manage containers
  context     Manage contexts
  image       Manage images
  manifest    Manage Docker image manifests and manifest lists
  network     Manage networks
  node        Manage Swarm nodes
  plugin      Manage plugins
  secret      Manage Docker secrets
  service     Manage services
  stack       Manage Docker stacks
  swarm       Manage Swarm
  system      Manage Docker
  trust       Manage trust on Docker images
  volume      Manage volumes
Commands:
  attach      Attach local standard input, output, and error streams to a running container
  build       Build an image from a Dockerfile
  commit      Create a new image from a container's changes
  cp          Copy files/folders between a container and the local filesystem
  create      Create a new container
  diff        Inspect changes to files or directories on a container's filesystem
  events      Get real time events from the server
  exec        Run a command in a running container
  export      Export a container's filesystem as a tar archive
  history     Show the history of an image
  images      List images
  import      Import the contents from a tarball to create a filesystem image
  info        Display system-wide information
  inspect     Return low-level information on Docker objects
  kill        Kill one or more running containers
  load        Load an image from a tar archive or STDIN
  login       Log in to a Docker registry
  logout      Log out from a Docker registry
  logs        Fetch the logs of a container
  pause       Pause all processes within one or more containers
  port        List port mappings or a specific mapping for the container
  ps          List containers
  pull        Pull an image or a repository from a registry
  push        Push an image or a repository to a registry
  rename      Rename a container
  restart     Restart one or more containers
  rm          Remove one or more containers
  rmi         Remove one or more images
  run         Run a command in a new container
  save        Save one or more images to a tar archive (streamed to STDOUT by default)
  search      Search the Docker Hub for images
  start       Start one or more stopped containers
  stats       Display a live stream of container(s) resource usage statistics
  stop        Stop one or more running containers
  tag         Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
  top         Display the running processes of a container
  unpause     Unpause all processes within one or more containers
  update      Update configuration of one or more containers
  version     Show the Docker version information
  wait        Block until one or more containers stop, then print their exit codes
Run 'docker COMMAND --help' for more information on a command.
To get more help with docker, check out our guides at https://docs.docker.com/go/guides/

Shouldn't buildx come bundled? At least that's how I read the documentation.
What am I missing?

[tonistiigi]

Depends on how docker was installed. Buildx does come bundled with the official docker-ce-cli packages (eg. https://download.docker.com/linux/ubuntu/dists/xenial/pool/stable/amd64/) . You don't need to define DOCKER_CLI_EXPERIMENTAL anymore.

[tcurdt]

@tonistiigi docker version does not give information about whether buildx is available. Correct?

Looking at

• https://github.com/docker-library/docker/blob/ec5d64f9611da8f8b19c9c5c4acc04b9397174e6/20.10/Dockerfile
• https://hub.docker.com/layers/docker/library/docker/latest/images/sha256-e6dd1262602faf3ae9c5dd84f76d4f2b5232ba24315fd3df9e9b28c14f0d4f97?context=explore

it seems like buildx is not part of the docker:latest image.
I guess it's easy enough to create such an image - but isn't there an official one?

[tonistiigi]

It is not included in the docker:latest image. Feel free to make an issue for it in https://github.com/docker-library/docker if you think it should be.

[crazy-max]

@tcurdt docker-library/docker#243. I've included buildx and BuildKit in an image derived from the official one here if you want to take a look.

[crazy-max]

#656