TL;DR

Below are steps for VSCode remote development on Windows 11 through SSH of WSL2 Ubuntu.

Why not use Windows SSH? I need some packages for SSH that are only available with Ubuntu.

• On Windows 11

  • Install WSL2 Ubuntu
  • Install VSCode
  • Install VSCode Remote Extension Pack
  • VSCode SSH from WSL
    • SSH from interactive shell to source ~/.bashrc

• In WSL2 Ubuntu

  • Generate SSH key and add to ssh-agent
  • Add SSH key to GitHub
  • Auto start ssh-agent
  • Install Kerberos
  • Customize ~/.ssh/config
• Verify that your SSH command from a WSL2 Ubuntu terminal works.
• Typing that command into VSCode should give you the full remote editing experience!

How it started

I got a great deal ($500 off!) on a Dell Inspiron 16 Plus laptop this Black Friday 🤑

The laptop runs Windows 11, but I usually use Ubuntu for development. However, I’m tired of maintaining the compatibility hacks I need with my previous laptop that I dual booted Ubuntu. For example, the microphone audio sounds deep fried, and the solution is hacking around in PulseAudio config files.

In my current research project, I work over a SSH connection to a CSAIL server. Rather than edit locally and copy changes to remote, I prefer using VSCode Remote SSH to directly edit remote files.

Maybe I could set up my preferred workflow with Windows?

Environment

On Windows, installing VSCode, installing SSH, and creating new SSH keys is straightforward.

Configuring the ssh-agent with automatic startup and the key is also simple.

The last step is to check if I can SSH with Powershell to the server. For security purposes, I must connect to the target server deep-gpu-1.csail.mit.edu through the jump server jump.csail.mit.edu. For both connections, I must type my password.

Good news! I can SSH successfully. What about VSCode?

Once I install VSCode Remote Development, I type the same Powershell SSH command into the VSCode prompt. After connecting, I can edit the remote files directly.

Success!

. . . except typing my password twice is annoying 😩

On my previous laptop, I set up passwordless SSH with Kerberos tickets. Then I only type my password once every 12 hours instead of twice every time I login. However, these steps are for Ubuntu.

The CSAIL website also has a Windows version. Maybe that would work?

Kerberos on Windows

3.2.x

The CSAIL TIG website shows instructions for installing Kerberos on Windows (KfW) 3.2.x.

Following the instructions steps, I install the 64-bit version of KfW before the 32-bit version.

I open the KfW GUI, create a new Kerberos ticket, and try connecting to the server.

Like on my previous laptop, I expect to see the server login text after a short delay.

Unluckily, I see the password prompt.

The website mentions a newer KfW, which I could try instead?

4.1.x

I remove the previous KfW before installing KfW 4.1.x.

The GUI looks nicer, which seems more promising.

However, after I create a new Kerberos ticket and connect, I still see password prompts.

At this point, I file a help request with TIG, and they quickly confirm that using KfW with CSAIL servers is no longer supported.

Do I need to dual boot Ubuntu now? Not just yet.

Ubuntu inside Windows!

Microsoft recently released Windows Subsystem for Linux 2 (WSL2), a Linux kernel inside Windows. This feature is promising because I could have the convenience of Windows but develop inside a lightweight Ubuntu environment.

SSH

Installing WSL2 Ubuntu is simple, and I can set up my SSH keys and config with the same ~/.ssh folder as my previous laptop.

Adding my key to the ssh-agent is also identical. The only difference is that WSL2 Ubuntu does not support systemd, so the ssh-agent does not already start automatically. However, there exist multiple solutions, and I choose to install keychain and write eval $(keychain --eval -q ~/.ssh/id_ed25519) to my ~/.bashrc.

I can successfully open an SSH connection by typing my password twice. So far, so good.

Kerberos

Since I already see differences between WSL2 and desktop Ubuntu, I began to worry slightly that Kerberos login would not work with WSL2.

I again follow the Ubuntu Kerberos steps,

Luckily, I can connect to the server from WSL2 with no password prompt.

VSCode hack

However, I still need to connect my VSCode installed on Windows. How can I force VSCode to SSH from Ubuntu?

Fortunately, I find this thread on Stack Overflow. VSCode offers amazing customization for developers, so it’s no surprise that we can change what SSH executable VSCode runs.

The default executable is the ssh on the PATH, which would be the Windows SSH executable. The trick is replacing the SSH executable with a ssh.bat file that pipes VSCode arguments %* into the command C:\Windows\system32\wsl.exe ssh %*. When VSCode runs the .bat file, it will run in a WSL shell the ssh command with arguments %*.

Forward ssh-agent

I soon encounter an issue where I can git push properly in Windows terminal but encounter a public key error in a VSCode terminal.

Running ssh -T git@github.com also fails with a public key error, so my ssh-agent is not forwarded properly.

After some wrong approaches like modifying local VSCode settings or the remote SSH config, I finally realize the issue is that wsl.exe does not source ~/.bashrc.

After searching through WSL2 Github Issues, I found a helpful diagram of how a non-interactive shell like wsl.exe works. The new workaround is to run C:\Windows\system32\wsl.exe bash -ic 'ssh %*' to SSH with an interactive shell.

Once I modify the ssh.bat with the new command, I can now git push with no errors.

How it’s going

I finally have my preferred setup of VSCode remote development on Windows 😄

The workarounds I needed are somewhat messy but so much cleaner than dual booting Ubuntu and fixing hardware compatibility issues!