Logo

Armand.nz

Home / About / Linkedin / Github

Getting started with Docker for Arm using buildx

#docker #arm #buildx |

Getting started with Docker for Arm using buildx on Linux

First install buildx as a docker CLI plugin. This requires using Docker 19.03. A limited set of functionality works with older versions of Docker when invoking the binary directly.

  1. Make sure Docker is installed and is 19.03 or greater

     docker version | grep Version  
 Version: 20.10.6

buildx install options

There are three options to get buildx on Linux:

  1. Use buildx directly from the test version of docker: buildx comes bundled with Docker CE starting with 19.03, but requires experimental mode to be enabled on the Docker CLI. To enable it, "experimental": "enabled" can be added to the CLI configuration file ~/.docker/config.json. An alternative is to set the DOCKER_CLI_EXPERIMENTAL=enabled environment variable.

     docker version | grep Experimental  
 Experimental: true

  2. Binary release: Download the latest binary release from https://github.com/docker/buildx/releases/latest and copy it to ~/.docker/cli-plugins folder with name docker-buildx.

    For example,

     wget https://github.com/docker/buildx/releases/download/v0.8.2/buildx-v0.8.2.linux-amd64  
 mkdir -p ~/.docker/cli-plugins  
 mv buildx-v0.8.2.linux-amd64 ~/.docker/cli-plugins/docker-buildx

    Change the permission to execute:

     chmod a+x ~/.docker/cli-plugins/docker-buildx

  3. Building buildx: See build instructions from the project page

Confirm buildx is installed

  1. To confirm buildx is now installed run the help and the version command.

     $ docker buildx --help  
    
 Usage: docker buildx COMMAND  
 Build with BuildKit  
    
 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  
 inspect Inspect current builder instance  
 ls List builder instances  
 rm Remove a builder instance  
 stop Stop builder instance  
 use Set the current builder instance  
 version Show buildx version information

## Register Arm executables to run on x64 machines

  1. Install the instruction emulation to register Arm executables to run on the x86 machine. For best results, the latest qemu should be used. If an older qemu is used some application may not work correctly on the x86 hardware.

     docker run --rm --privileged docker/binfmt:820fdd95a9972a5308930a2bdfb8573dd4447ad3

  2. This lists the supported platforms you can build from.

    docker buildx ls  
NAME/NODE DRIVER/ENDPOINT STATUS PLATFORMS  
default * docker  
default default running linux/amd64, linux/386, linux/arm64, linux/ppc64le, linux/s390x, linux/arm/v7, linux/arm/v6

    In my case, this includes the following platforms:

    • linux/amd64: Linux x64
    • linux/arm64: ARM 64
    • linux/riscv64: 64-bit RISC-V
    • linux/ppc64le: 64-bit little-endian PowerPC
    • linux/s390x: 64-bit Linux on IBM Z
    • linux/386: Linux x86
    • linux/arm/v7: ARM v7 (32-bit)
    • linux/arm/v6: ARM v6 (32-bit)

    The docker/binfmt has been updated with the latest qemu and replaces any previous instructions that call for linuxkit/binfmt:v0.7.

  3. Verify the qemu handlers are registered properly run the command below and Make sure the first line of the output is “enabled”:

    Note: That the handler registration doesn’t survive a reboot, but can be added to the system start-up scripts.

     cat /proc/sys/fs/binfmt_misc/qemu-aarch64  
    
 enabled  
 interpreter /usr/bin/qemu-aarch64  
 flags: OCF  
 offset 0  
 magic 7f454c460201010000000000000000000200b7  
 mask ffffffffffffff00fffffffffffffffffeffff

Try buildx

  1. Have the Dockerfile ready

     ls  
 Dockerfile file1 file2

  2. Now, use buildx to build for multiple architectures and push to your registry, e.g. Docker hub.

     # Create a builder first  
 docker buildx create --use --name build --node build --driver-opt network=host  
 docker buildx create --name mybuilder  
 docker buildx use mybuilder  
 docker buildx inspect --bootstrap  
    
    
 # Build from local Dockerfile in this directory (".")  
 docker buildx build --platform linux/amd64,linux/arm64,linux/arm/v7,linux/arm/v6 --push -t armsultan/hello-world .

  3. Output a buildx summary. The imagetools inspect command confirms that the image has support for the three architectures specified in the build command and prints the full image ID for each architecture.

     docker buildx imagetools inspect armsultan/hello-world  
    
 Name: docker.io/armsultan/hello-world:latest  
 MediaType: application/vnd.docker.distribution.manifest.list.v2+json  
 Digest: sha256:76e4f38e56e877d9889e9c00e6c83e93bb5e2b8ed004abd173f087b0bc32d5ff  
    
 Manifests:  
 Name: docker.io/armsultan/hello-world:latest@sha256:d6bc3f9ab6379fc3300cc5b247faca80a939ba977c5a7e9df18f625222f1ddc9  
 MediaType: application/vnd.docker.distribution.manifest.v2+json  
 Platform: linux/amd64  
    
 Name: docker.io/armsultan/hello-world:latest@sha256:84788fca53f0b09d8459ba84e38a84acd6ab54cf257596e3ce1c441061c21978  
 MediaType: application/vnd.docker.distribution.manifest.v2+json  
 Platform: linux/arm64  
    
 Name: docker.io/armsultan/hello-world:latest@sha256:b86cf67b10eeaeceb8a5314e6dfa3b040dfc9a4f834da48044d95f70df32e2df  
 MediaType: application/vnd.docker.distribution.manifest.v2+json  
 Platform: linux/arm/v7

  4. If I wanted to build a bunch of other platforms I could run the following:

     docker buildx build -t andrewlock/wait-for-dependencies:latest --platform linux/amd64,linux/arm64,linux/ppc64le,linux/s390x,linux/386,linux/arm/v7,linux/arm/v6 .

  5. the ` –push` option on the build command will push the images to our container registry

References:

comments powered byDisqus

Copyright © Armand