Vagrant Docker Provider Image

This repo will build a docker image that can be used as a provider for Vagrant as a Linux development environment.

The ready made Docker Hub image can be found here: rofrano/vagrant-provider:ubuntu

Why Vagrant with Docker?

This was inspired by Apple's introduction of the M1 chip which is ARM based. That means that solutions which use Vagrant and VirtualBox will not work on Apple M1 because VirtualBox requires an Intel processors. This lead me to find a solution for a virtual development environment that works with ARM and thus Apple M1 computers. You can find out more information about why I built it here:

Developing on Apple M1 Silicon with Virtual Environments

Docker has introduced Docker Desktop for Apple silicon that runs Docker on Macs that have the Apple M1 chip. By using Docker as a provisioner for Vagrant, we can simulate the same experience as developers using Vagrant with VirtualBox. This is one case where you actually do want a Docker container to behave like a VM.

Image Contents

The ubuntu image is based on Ubuntu 21.04 and the debian image is Debian 11. Both contain the packages that are needed for a valid vagrant box. This includes the vagrant userid with password-less sudo privileges. It also contains as sshd server. Normally, it is considered a bad idea to run an ssh daemon in a Docker container but in this case, the Docker container is emulating a Virtual Machine (VM) to provide a development environment so it makes perfect sense. ;-)

Example Vagrantfile

Here is a sample Vagrantfile that uses this image:

Vagrant.configure("2") do |config|
  config.vm.hostname = "ubuntu"

  config.vm.provider :docker do |docker, override|
    override.vm.box = nil
    docker.image = "rofrano/vagrant-provider:ubuntu"
    docker.remains_running = true
    docker.has_ssh = true
    docker.privileged = true
    docker.volumes = ["/sys/fs/cgroup:/sys/fs/cgroup:rw"]
    docker.create_args = ["--cgroupns=host"]
    # Uncomment to force arm64 for testing images on Intel
    # docker.create_args = ["--platform=linux/arm64"]     
  end  
end

Example: Docker in Docker

This image will also run docker in docker. To install docker using vagrant add this to the Vagrantfile:

  # Install Docker and pull an image
  config.vm.provision :docker do |d|
    d.pull_images "alpine:latest"
  end

This will install Docker and pull the alpine:latest image. You can pull and run any image you'd like.

Example: ARM64

If you want to test the ARM version on an Intel computer just uncomment the docker.create_args line which adds --platform=linux/arm64 to the arguments. This will add the --platform flag to the docker run command to force the aarch64 image to be used via qemu.

There is also a debian variant to this image that is based on debian:11. That can be used by changing the docker.image line above to use the rofrano/vagrant-provider:debian image instead like this:

    docker.image = "rofrano/vagrant-provider:debian"

Command Line Usage

To use this provider, add the --provider flag to your vagrant command:

vagrant up --provider=docker

This will use this the docker image specified in your Vagrantfile as the base box.

You can also run this using the provided Makefile with:

make run

Build Multi-Archtecture Image

To build this image you must use buildx and build it for multiple architectures so that it can run on both Intel and ARM machines.

Initialize builder

If you don't have a builder you must first create one:

% export DOCKER_BUILDKIT=1
% docker buildx create --use --name=qemu
qemu
% docker buildx inspect --bootstrap

The provided Makefile will do this for you with:

make init

This will initialize the buildx provider as above.

Building the default Ubuntu image

Then you can build the multi-platform image like this (where {account} is the name of your Docker Hub account):

docker buildx build --file Dockerfile.ubuntu --tag {account}/vagrant-provider:ubuntu --platform=linux/amd64,linux/arm64 --push .

This will use QEMU to build a multi-platform image and push it to docker hub.

You can also build your image with make:

make build REGISTRY={your account}

It is better if you set an environment varaible called REGISTRY and it will be picked up by make. For example, if your Docker Hub account name is foo you would use:

export REGISTRY=foo
make build

This will ensure that all of the make commands will use your registry and not mine (i.e., rofrano)

Building image variants

The default image is ubuntu but you can build the debian image by adding the argument IMAGE_TAG=debian like this:

make build IMAGE_TAG=debian

This will use the Dockerfile.debian and push to an image called rofrano/vagrant-provider:debian

If you want to add your own variant, just create a Dockerfile with the variant name as the extension and it will be picked up (e.g., Dockerfile.alpine). Then you can use make build IMAGE_TAG=alpine to build and push that image.

Remove the buildx instance

When not needed, you can safely stop and/or remove the buildx containers with the following commands:

docker buildx stop
docker buildx rm

This can also be accomplised with:

make remove

Credits

A huge thanks to Matthew Warman who provided the Dockerfile from mcwarman/vagrant-provider as the bases for my Dockerfile using systemd. He added all the magic to make it work and I am very greateful for his generosity.