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DockerInWSL

This Project is meant to be a minimal alternative to Docker Desktop. It uses WSL2 and a customized Ubuntu Container-Image as a lightweight replacement for the Moby VM.

How to install?

The easiest way is to use our private WinGet Repository. See cloudflightio/winget-pkgs for details.

Please verify that you have WSL2 installed and activated! Verify that you got a 5.x Linux Kernel Version (preferable 5.10.x or later) installed. Run wsl --status to gather info about your WSL version. Try wsl --install and wsl --update to get the latest WSL install. See WSL installation instructions for more information.

ℹ️ You can uninstall the default Ubuntu distribution after the installation of DockerInWSL is completed using wsl --unregister ubuntu. It is not needed for DockerInWSL to work.

If you are one of the eager kind just execute the following in a privileged PowerShell window:

winget source add --name cloudflight https://cloudflightio.github.io/winget-pkgs
winget source update --name cloudflight
winget install dockerinwsl

How to use?

There are different ways to use Docker on Windows.

Wrapper Scripts

There are 3 cli-scripts that can be used to control docker in WSL. Just enter one of the following command inside a powershell or cmd window:

  • docker: Simple bat-file wrapper for wsl -d clf_dockerinwsl -- docker <args>.
  • docker-compose: Also just a simple wrapper for wsl -d clf_dockerinwsl -- docker-compose <args>
  • docker-wsl: A control-tool to interact with the wsl-distro and services inside it. For now it supports start,stop,restart,show-logs and show-config

Direct WSL

Another way is to directly call Docker using the WSL binary:

  • Open a Powershell window (no "As Administrator" needed).
  • Navigate to the folder you want to use Docker in.
  • Run wsl -d clf_dockerinwsl -- docker ... to execute the Docker CLI directly or use wsl -d clf_dockerinwsl to open a shell inside the docker-enabled WSL2 distribution.

ℹ️ You can also use docker-compose this way.

IntelliJ

If you are using IntelliJ (like we do) it is quite easy to enable Docker with DockerInWSL:

  • Press Services (Alt+8) in the navigation bar at the bottom.
  • Press Add Service (Alt+Insert) and select "Docker Connection".
  • Give the connection a name and select "TCP socket" as the connection method.
  • Set tcp://localhost:2375 as the "Engine API URL" and hit OK.

Now you should be able to connect to Docker from within IntelliJ and control your Containers/Images/Networks/Volumes.

ℹ️ Make sure to call docker-compose up in the Linux environment with wsl -d <Distro> docker-compose up -d, because using IntelliJ IDEA for creation would execute docker.exe, causing errors as soon as you attempt to map volumes.

ℹ️ GUI actions for docker-compose up (e.g. "Run" icon in Docker Compose file editor) currently are not supported by IntelliJ if Docker binaries are stored/executed within WSL, which is the case with DockerInWSL.

TestContainers

We are using TestContainers quite a lot. After installing DockerInWSL the environment variable DOCKER_HOST should be set to tcp://localhost:2375. To make this change visible to all applications it is recommended to restart your machine. A simple close and reopen of most Apps should be sufficient, but it's Windows right ;)

After that, TestContainers should recognize the installation and "just work".

How to configure?

In some cases it might be necessary to configure part of DockerInWSL manually. There are special config-files located at %APPDATA%\DockerInWSL\config (you can use docker-wsl show-config to open the folder). Just edit them to your needs and restart the services using docker-wsl restart.

Currently the following config-files are available:

  • custom_dns.conf: Additional dnsmasq config that can be used to add additional host-records or dns-servers. See https://wiki.archlinux.org/title/dnsmasq#DNS_server for more information on the config format
  • daemon.json: This is the central docker daemon config file. You can, besides other settings, add insecure registries or change the default subnet if it collides with your network settings. Have a look at our wiki or the official documentation.

How does it work?

This project is a result of our internal dev setup which uses Docker and TestContainers to provide a convenient way to work with cloud native environments. We used "Docker Desktop" in the past but their 2021 policy change forced us to rethink that choice and we came up with an alternative solution. Our new (this) setup uses WSL2 and Ubuntu with Docker to provide a simple replacement. Currently, it does miss some convenience features, like a management GUI but should also be more lightweight and easier to use.

The whole installation process is handled by MSI and PowerShell. At its core, the installer is performing the following steps:

  • Check whether a newer or the same version is installed. → Abort installtion if this is the case.
  • Check whether WSL is installed properly. → Abort if no WSL2 install is found. (We decided to avoid installing it automatically because it can have some side-effects in complex environments)
  • Copy all scripts and a TAR export of our Container-Image to %PROGRAMFILES%\DockerInWSL.
  • Create the directory %APPDATALOCAL%\DockerInWSL, a startup Shortcut in shell:startup and some additional links in the start-menu all starting with "DockerInWsl".
  • Set the DOCKER_HOST user environment variable to tcp://localhost:2375.
  • Add the %PROGRAMFILES%\DockerInWSL\scripts directory to the users PATH variable.
  • Run install.ps1:
    • Check whether a DockerInWSL distribution is already installed in WSL2
      • If one is found, create a backup of /var/lib/docker and copy it to the Windows file system under %APPDATALOCAL%\DockerInWSL\backup.tar.gz. (We are working on a better way to handle this.)
      • After that, delete the current distribution using wsl unregister <distro>. This deletes the entire docker-storage and leads to a complete wipe (from a Docker point of view).
      • You might ask "Why not just leave the distribution be?": We are currently using the stock dind Image to reduce maintenance effort as much as possible. Using this makes in-place upgrades quite hard, we, therefore, decided to go "the docker way", using only destroy/recreate as update path. We might reconsider this in future versions but for now, it seems like the best approach.
    • Import the DockerInWSL TAR from %APPDATALOCAL%\DockerInWSL\image.tar to %APPLOCALDATA\DockerInWSL\wsl using wsl --import.
    • Check whether there is a file at %APPDATALOCAL%\DockerInWSL\backup.tar.gz and, if so, extract it. If this fails do not abort the installation because the old distribution is already gone. If you find your WSL Docker empty after an update, check whether %APPDATALOCAL%\DockerInWSL\backup.tar.gz exists and try to extract it manually
    • Finally, the startup script docker-wsl.bat is called to start Docker.
  • Additionally some registry keys are created to support proper updates/uninstalling using MSI.