Converting a SQL Server Docker image to a WSL2 Distribution

Windows Subsystem for Linux is probably my favourite feature of Windows 10. It gives us the ability to run full blown linux distributions on our Windows 10 desktop. This allows us to utilise the cool features of linux (grep ftw) on Windows 10.

I’ve been playing around a bit with WSL2 and noticed that you can import TAR files into it to create your own custom distributions.

This means that we can export docker containers and run them as WSL distros!

So, let’s build a custom SQL Server 2019 docker image, run a container, and then import that container into WSL2…so that we have a custom distro running SQL Server 2019.

Note…this is kinda cool as WSL2 is not (currently) a supported platform to install SQL on Linux: –

Anyway, let’s run through the process.

Here’s the dockerfile for the custom SQL Docker image: –

FROM ubuntu:20.04

RUN apt-get update && apt-get install -y wget software-properties-common apt-transport-https

RUN wget -qO- | apt-key add -

RUN add-apt-repository "$(wget -qO-"

RUN apt-get update && apt-get install -y mssql-server

CMD /opt/mssql/bin/sqlservr

Pretty standard, following the SQL on Linux install instructions here.

OK, let’s build the image: –

docker build -t sqlserver2019 .

Now run a container from the new custom image: –

docker container run -d `
--publish 1433:1433 `
--env MSSQL_SA_PASSWORD=Testing1122 `
--name sqlcontainer1 `

Confirm that the container is running: –

docker container ls

OK, now we’re going to rename the instance in the container for no other reason that we want the instance name not to be the container ID when we run it as a WSL2 Distro: –

mssql-cli -S localhost -U sa -P Testing1122 -Q "SELECT @@SERVERNAME AS [InstanceName];"

mssql-cli -S localhost -U sa -P Testing1122 -Q "sp_dropserver [8622203f7381];"

mssql-cli -S localhost -U sa -P Testing1122 -Q "sp_addserver [sqlserver2019], local;"

Stop, then start the container and confirm the rename has been successful: –

docker stop sqlcontainer1

docker start sqlcontainer1

mssql-cli -S localhost -U sa -P Testing1122 -Q "SELECT @@SERVERNAME AS [InstanceName];"

Cool! Now, stop the container again: –

docker stop sqlcontainer1

Right, now we can export the container to a tar file: –

docker export sqlcontainer1 -o C:\temp\sqlcontainer1.tar

Once the export is complete we can then import it into WSL2: –

wsl --import sqlserver2019 C:\wsl-distros\sqlserver2019 C:\temp\sqlcontainer1.tar --version 2

Here’s what the code above is doing…

  • sqlserver2019 – the name of the new WSL distro
  • C:\wsl-distros\sqlserver2019 – The path where the new distro will be stored on disk
  • C:\temp\sqlcontainer1.tar – The location of the tar file we are importing
  • version 2 – WSL version of the new distro

Confirm that the new distro is in WSL2: –

wsl --list --verbose

Great stuff, the distro has been imported. Now we need to start it by running SQL. We’re going to use the setsid command to start up SQL here, as if we didn’t…the SQL log would write to our current session and we’d have to open up another powershell window: –

wsl -d sqlserver2019 bash -c "setsid /opt/mssql/bin/sqlservr"

Verify the distro is running: –

wsl --list --verbose

There’s our distro running! And we also execute ps aux against the distro to see if SQL is running: –

wsl -d sqlserver2019 ps aux

Cool! So now we can connect to SQL running in the distro with (using instead of localhost): –

mssql-cli -S -U sa -P Testing1122 -Q "SELECT @@SERVERNAME"

Excellent stuff! We have a new WSL2 distro running the latest version of SQL Server 2019!

So we can do our work and when we’re finished we can close down the distro with: –

wsl -t sqlserver2019

And if we want to get rid of the new distro completely: –

wsl --unregister sqlserver2019

Pretty cool! Ok, I admit…most people would prefer to run SQL in a container for this kind of stuff BUT it does give us another option…and having more options is always a good thing to have…right?


Thanks for reading!

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