Dockerhost is a small tool that sets up a virtual machine hosting a Docker daemon. The docker client running locally on Mac can run all its Docker workloads on the docker host.

Install dockerhost:

brew install 4d63/dockerhost/dockerhost

Create a docker host:

dockerhost create

Set the DOCKER_HOST environment variable:

eval $(dockerhost env)

Use Docker as you normally do:

docker build ...

Docker has been a pivotal technology in my toolbox for a number of years. For deployment yes, but more so for my development environment. I’m a Linux native living in a Mac world and Docker has made it possible to develop software using the Linux tools I’m familiar with. Most recently I’ve been using Docker’s Mac product, Docker Desktop, like many developers who use Macs.

As wonderful as it is that Docker provides me with reproducible development environments, Docker Desktop hasn’t been all rainbows and sunshine. For about a year I’ve been experiencing random high CPU usage with Docker Desktop. It occurs at the most inopportune time, high CPU Docker, causing my computer to crawl to a halt, fans spinning loudly like a jet taking off.

I’ve been wanting to look at alternatives to Docker Desktop for sometime, but for the most part there was always something else more important to do. However, on August 31st, 2021, Docker announced a new pricing model for Docker Desktop. I don’t have any huge issue with this, but it’s inconvenient and the friction of “do I need a subscription?” flowchart was the final push I needed to explore other options for virtualized or containerized workflows on Mac. I tried Podman, VMWare Fusion’s vctl, qemu, Vagrant, and Multipass, but let’s face it, Docker is convenient and its ubiquity is unparalleled.

Thankfully all we need to run Docker on Mac without Docker Desktop is a virtual machine to host the Docker daemon. The Docker client is available for Mac and can connect over SSH or TCP to any remote daemon.

Enter Multipass. Multipass is a convenient tool for launching Ubuntu virtual machines. It turns out it works really well on Mac and at this point might be the simplest lowest-effort tool for running Linux VMs on Mac, assuming you’re into Ubuntu.

Needing to setup a virtual machine from scratch with Docker is tedious, and so I created Dockerhost to wrap the process. Dockerhost is a script that wraps Multipass and launches Ubuntu VMs that have Docker running and accessible over TCP.

Dockerhost and Multipass are not as feature rich as Docker Desktop, but they have what I need for my workflow, and so far I haven’t experienced those high CPU woes.

I’m using Dockerhost for my own Docker driven development environments. If you have any feedback, please open an issue at:

https://github.com/leighmcculloch/dockerhost

Why not Podman? I’m excited about Podman and I expect to be using it in the future, but it isn’t compatible with VSCode and I ran into a few issues running images so it isn’t quite a Docker replacement for me. I’m very keen to use it, and I just had my first contribution to Podman’s sibling, Buildah, merged last week, which is thrilling. It’s not quite a drop-in replacement for my workflow yet but I’ll be keeping my eye on it.

Why not qemu? You overestimate my current ability and the amount of free time I have. ๐Ÿ˜…