Work In Progress!

Setting up systemd and installing k3s works!
Setting up internet connection in WSL2 Ubuntu 20.04 behind a Corporate VPN works!
... but these two together don't work. Needs to be debugged further

$ sudo ./wsl-vpnkit-setup.sh --no-docker
Setup complete!
Job for wsl-vpnkit.service failed because the control process exited with error code.
See "systemctl status wsl-vpnkit.service" and "journalctl -xe" for details.
$ systemctl status wsl-vpnkit.service
● wsl-vpnkit.service
     Loaded: loaded (/etc/init.d/wsl-vpnkit; generated)
     Active: failed (Result: exit-code) since Fri 2021-09-24 22:42:22 EEST; 15s ago
       Docs: man:systemd-sysv-generator(8)
    Process: 1092 ExecStart=/etc/init.d/wsl-vpnkit start (code=exited, status=1/FAILURE)

systemd[1]: Starting wsl-vpnkit.service...
systemd[1]: wsl-vpnkit.service: Control process exited, code=exited, status=1/FAILURE
systemd[1]: wsl-vpnkit.service: Failed with result 'exit-code'.
systemd[1]: Failed to start wsl-vpnkit.service.

Get k3s working on wsl2 Ubuntu 20.04

Requirements:

WSL2: https://docs.microsoft.com/en-us/windows/wsl/install
Ubuntu 20.04 from the Microsoft store: https://www.microsoft.com/en-us/p/ubuntu-2004-lts/9n6svws3rx71?activetab=pivot:overviewtab

systemd

Install some dependencies:

sudo apt-get update && sudo apt-get install -yqq daemonize dbus-user-session fontconfig

Copy the necessary scripts:

sudo cp start-systemd-namespace /usr/sbin/start-systemd-namespace && \
sudo cp enter-systemd-namespace /usr/sbin/enter-systemd-namespace && \
sudo chmod +x /usr/sbin/start-systemd-namespace && \
sudo chmod +x /usr/sbin/enter-systemd-namespace

Copy-paste the contents of sudoers to /etc/sudoers. You can only do it with:

sudo visudo

Make sure start-systemd-namespace is executed when starting a bash session:

sudo sed -i 2a"# Start or enter a PID namespace in WSL2\nsource /usr/sbin/start-systemd-namespace\n" /etc/bash.bashrc

Set the following environment variables in a command line:

setx WSLENV BASH_ENV/u
setx BASH_ENV /etc/bash.bashrc

Logout from wsl2 Ubuntu 20.04

logout

Terminate the Ubuntu instance and make sure it's not running:

wsl --terminate Ubuntu-20.04
wsl --list --running

k3s

Install k3s in WSL by running:

curl -sfL https://get.k3s.io | sh -

Copy the kube config from wsl to your windows host.

# Save previous kube config file, don't want to get overwritten
cp /mnt/c/Users/andra/.kube/config /mnt/c/Users/<user>/.kube/config-backup
# checkout k3s kube config file
sudo cat /etc/rancher/k3s/k3s.yaml
# copy the k3s kube config file to user directory
sudo cp /etc/rancher/k3s/k3s.yaml /mnt/c/Users/<user>/.kube/config

# get the ip address of WSL
ip addr show dev eth0
# replace localhost ip address (127.0.0.1) with WSL's from the previous command
sed -i -e 's/127.0.0.1/<ip-from-prev-command>/g' /mnt/c/Users/<user>/.kube/config

Troubleshooting

Running bash in a broken WSL:

wsl bash --norc

In case the scripts that you copied cause WSL not to start, you can always delete them manually from windows.

Acknowledgements

Scripts: enter-systemd-namespace, start-systemd-namespace

Taken from: https://forum.snapcraft.io/t/running-snaps-on-wsl2-insiders-only-for-now/13033/4

Fix for scripts so that they work with Ubuntu-20.04

Taken from: Reddit user inspeculation, https://www.reddit.com/r/bashonubuntuonwindows/comments/gc8lle/usrsbindaemonize_no_such_file_or_directory/ thread.

Note: the fixes from this thread are already incorporated to enter-systemd-namespace and start-systemd-namespace.

Going forward (for you and others who try this), a couple of tweaks are needed for this to work with 20.04.

First, the original author has updated his scripts fairly regularly, he's clear about the process, and there's a helpful comment thread, so get his code here:https://forum.snapcraft.io/t/running-snaps-on-wsl2-insiders-only-for-now/13033

Outline of the steps: install three things, add two bash script files to /usr/sbin (one with chmod +x), alter sudoers in visudo, add a line to .bashrc, and add two environment variables.

(If you've done this process before on the same computer -- I did it on an 18.04 that started life pre-WSL2 as Ubuntu 16.04, now doing it on a WSL Ubuntu 20.04 -- those variables will already be set, but there's no harm in making sure.)

The scripts reference the .systemd-env file, so before you do anything with the scripts, make sure you have one even if it's empty. It should be placed at /root

Further advice: check every character in the scripts after copy-pasting and before saving. It only takes a couple of minutes and could prevent you mangling your distro. I noticed a weirdly formatted line after pasting in one of them; it turned out to have a few duplicated characters. It only happened once but that's a big yikes amirite.

Okay, the tweaks...

ps -ef should be ps -efw: According to the latest comment, the `ps -ef` commands (there are three at last count) need to be changed to `ps -efw`. 'Without that “-w” the output is truncated, one of the calls will fail to find in start, the other will succeed and will not spawn anything, which causes my gnome-terminal sessions to instantly close after the first one.'

daemonize has moved: as the OP discovered, daemonize now installs to /usr/bin rather than /usr/sbin, so the reference to it in the enter-systemd-namespace script needs to be changed.

After completing all the steps, I exited bash, ran wsl --shutdown in PowerShell for good measure, and rebooted Windows just in case. It's working with no discernible issues.

Steps on how to reach k3s from Windows

Taken from: https://gist.github.com/ibuildthecloud/1b7d6940552ada6d37f54c71a89f7d00

andraspatka / k3s-wsl