Setting up docker buildx on Linux

Installation instructions for Ubuntu

To execute docker commands without sudo. We need to add username to the docker group

  • Find current username by typing who
  • Add username to docker group
  • Reboot system
$ who
vikaspogu :0           2020-12-05 10:10 (:0)
$ sudo usermod -aG docker vikaspogu
$ sudo reboot

Enable buildx

Create a new config.json file under ~.docker folder and enable experimental feature

$ mkdir ~/.docker
$ vim ~/.docker/config.json
 "experimental": "enabled"

Now you should be able to do multi arch builds

$ docker buildx build -t vikaspogu/test:v0.0.1 . --push --platform linux/arm64

If you encounter below error when trying to build image using buildx. You need to create new build instance

failed to solve: rpc error: code = Unknown desc = failed to solve with frontend dockerfile.v0: failed to load LLB: runtime execution on platform linux/arm64 not supported

Create new build instance for arm64

  • List existing buildx platforms
  • Create new build instance named arm64
  • Inspect build instance to verify arm64 platform exists
  • Set builder instance
  • Build multi platform image
$ docker buildx ls
default   docker                               
  default default                     running  linux/amd64, linux/386

# create the builder
$ docker buildx create  --name amr64 --platform linux/amd64,linux/arm64

# start the buildx
$ docker buildx inspect arm64 --bootstrap
Name:   arm64
Driver: docker-container

Name:      arm640
Endpoint:  unix:///var/run/docker.sock
Status:    running
Platforms: linux/amd64*, linux/arm64*, linux/riscv64, linux/ppc64le, linux/386, linux/arm/v7, linux/arm/v6, linux/s390x

# set current buidler instance
$ docker buildx use amr64

# build the multi images
$ docker buildx build -t vikaspogu/test:v0.0.1 . --push --platform linux/arm64

If you encounter /bin/sh: Invalid ELF image for this architecture error. Run following docker image and then build

$ docker run --rm --privileged multiarch/qemu-user-static --reset -p yes