Docker around its 19.x release updated its current Builder with the new image builder known as Buildkit. The official definition of the Builkit is outlined as BuildKit is a toolkit for converting source code to build artifacts in an efficient, expressive, and repeatable manner.
Buildkit provides much-needed features for building Docker images like Faster Build time by leveraging efficient caching mechanisms and by parallelizing building independent build stages, Building Multi-Architecture builds, etc. Thus improving the current experience in performance, storage management, and extensibility.
The above features can be accessed on a locally installed Docker setup is by using the command buildx
The following features/commands are provided by the buildx command
santosh@~*$:docker buildx
Usage: docker buildx [OPTIONS] COMMAND
Extended build capabilities with BuildKit
Options:
--builder string Override the configured builder instance
Management Commands:
imagetools Commands to work on images in registry
Commands:
bake Build from a file
build Start a build
create Create a new builder instance
du Disk usage
inspect Inspect current builder instance
ls List builder instances
prune Remove build cache
rm Remove a builder instance
stop Stop builder instance
use Set the current builder instance
version Show buildx version information
Run 'docker buildx COMMAND --help' for more information on a command.One of the commands used with buildx is the regular build command. Docker buildx is a Docker Plugin that extends the existing Docker build command, which provides some new features provided by the Buildkit mechanism. buildx executes all the processes in Parallel making the whole build process much faster.
santosh@figlet*$:docker buildx build -t santoshdts/figlet2 .
WARNING: No output specified with docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load
[+] Building 2.0s (6/6) FINISHED
=> [internal] load build definition from Dockerfile 0.0s
=> => transferring dockerfile: 429B 0.0s
=> [internal] load .dockerignore 0.0s
=> => transferring context: 2B 0.0s
=> [internal] load metadata for docker.io/library/alpine:latest 2.0s
=> [1/3] FROM docker.io/library/alpine:latest@sha256:bc41182d7ef5ffc53a40b044e725193bc10142a1243f395ee852a8d9730fc2ad 0.0s
=> => resolve docker.io/library/alpine:latest@sha256:bc41182d7ef5ffc53a40b044e725193bc10142a1243f395ee852a8d9730fc2ad 0.0s
=> CACHED [2/3] RUN apk update && apk update 0.0s
=> CACHED [3/3] RUN apk add figletAs you can see, the whole build process was completed in 2.0 seconds (Building 2.0s (6/6) FINISHED), Apart from this, we can even push the build artifact directly to our registery (If the Build process was successful) if we append the command with --push flag.
Another feature of Buildx is building an image for multiple architectures. For the above example, we didn't specify any particular platform and it was built for Linux/amd64
Now, if we build another image from the same Dockerfile, tag it and add the --platform Linux/amd64,Linux/arm64 flags and push it to the repository. We would see two different images built witha single command.
santosh@figlet*$:docker buildx build -t santoshdts/figlet2:multiarch --platform linux/amd64,linux/arm64 . --push
[+] Building 27.7s (14/14) FINISHED
=> [internal] load .dockerignore 0.0s
=> => transferring context: 2B 0.0s
=> [internal] load build definition from Dockerfile 0.0s
=> => transferring dockerfile: 429B 0.0s
=> [linux/arm64 internal] load metadata for docker.io/library/alpine:latest 6.2s
=> [linux/amd64 internal] load metadata for docker.io/library/alpine:latest 4.8s
=> [auth] library/alpine:pull token for registry-1.docker.io 0.0s
=> [linux/arm64 1/3] FROM docker.io/library/alpine:latest@sha256:bc41182d7ef5ffc53a40b044e725193bc10142a1243f395ee852a8d9730fc2ad 0.8s
=> => resolve docker.io/library/alpine:latest@sha256:bc41182d7ef5ffc53a40b044e725193bc10142a1243f395ee852a8d9730fc2ad 0.0s
=> => sha256:9b18e9b68314027565b90ff6189d65942c0f7986da80df008b8431276885218e 2.71MB / 2.71MB 0.7s
=> => extracting sha256:9b18e9b68314027565b90ff6189d65942c0f7986da80df008b8431276885218e 0.1s
=> [linux/amd64 1/3] FROM docker.io/library/alpine:latest@sha256:bc41182d7ef5ffc53a40b044e725193bc10142a1243f395ee852a8d9730fc2ad 0.0s
=> => resolve docker.io/library/alpine:latest@sha256:bc41182d7ef5ffc53a40b044e725193bc10142a1243f395ee852a8d9730fc2ad 0.0s
=> CACHED [linux/amd64 2/3] RUN apk update && apk update 0.0s
=> CACHED [linux/amd64 3/3] RUN apk add figlet 0.0s
=> [linux/arm64 2/3] RUN apk update && apk update 5.4s
=> [linux/arm64 3/3] RUN apk add figlet 2.7s
=> exporting to image 12.5s
=> => exporting layers 0.1s
=> => exporting manifest sha256:6384e8209bcbcb4ea65aa9b96192fa44beaf3ff83a66134a63682b06d0092692 0.0s
=> => exporting config sha256:dadb123e30490f1d2fd69a369ac198433f39486b67709b4618804c58859bf166 0.0s
=> => exporting manifest sha256:66ec3b271fa8019a988f5fd25b79acc485a7bd1d6dda3ad56b2135ea5a69217a 0.0s
=> => exporting config sha256:dc6836e012fd07180fe11e202b7448fa261be0a2b9fea80fd600c93b8a691918 0.0s
=> => exporting manifest list sha256:864ccb19106a1c5aeb675ce1f1f3485107f8a78fcf120c910203b24417df9e99 0.0s
=> => pushing layers 10.2s
=> => pushing manifest for docker.io/santoshdts/figlet2:multiarch@sha256:864ccb19106a1c5aeb675ce1f1f3485107f8a78fcf120c910203b24417df9e9 2.1s
=> [auth] santoshdts/figlet2:pull,push token for registry-1.docker.io 0.0s
=> [auth] santoshdts/figlet1:pull santoshdts/figlet2:pull,push token for registry-1.docker.io
Baked builds are high-level features that can be used to define automated build pipelines. They let you produce multiple images from a single build operation.
BuildKit supports high-level build concepts that go beyond invoking a single build command enabling efficient handles of multiple concurrent build requests and de-duplicating work. The build commands can be combined with general-purpose command runners (for example, make). However, these tools generally invoke builds in sequence and therefore cannot leverage the full potential of BuildKit parallelization, or combine BuildKit's output for the user. For this use case, we use a command called docker buildx bake.
The bake command supports building images from HCL, JSON, and Compose files. This is similar to docker-compose build, but allows all the services to be built concurrently as part of a single request. If multiple files are specified they are all read and configurations are combined.