docker

The docker repo contains the Dockerfile specification of the default image used by unity.

Requirements

The script used to build Docker images for unity builds images for multiple platforms. This uses the buildx plugin and so requires QEMU.

Install QEMU:

# Ubuntu example
sudo apt-get install -y qemu-user-static

(taken from an article on using buildx for multi architecture images).

Install cross-platform emulators for at least the target platforms:

docker run --privileged --rm tonistiigi/binfmt --install all

(taken from the buildx documentation.)

Create and use a builder (which will by default use the docker-container driver):

docker buildx create --name mybuilder
docker buildx use mybuilder

Verify the builder is using the docker-container driver and the target platforms supported:

docker buildx inspect --bootstrap

The output should be something like:

[+] Building 0.5s (1/1) FINISHED
 => [internal] booting buildkit                                                                                                                                                                                                                                                                                  0.5s
 => => starting container buildx_buildkit_mybuilder0                                                                                                                                                                                                                                                             0.5s
Name:   mybuilder
Driver: docker-container

Nodes:
Name:      mybuilder0
Endpoint:  unix:///var/run/docker.sock
Status:    running
Platforms: linux/arm64, linux/amd64, linux/riscv64, linux/ppc64le, linux/s390x, linux/386, linux/mips64le, linux/mips64

Run the script to build Docker images for unity:

./_scripts/buildDockerImage.sh -b

Omit the -b flag to also push the resulting multi-arch images to Docker Hub.