Setting Up LXD on WSL2 with systemd enabled Ubuntu 18.04

by Mike Levin

Wednesday, July 27, 2022

What a wonderful starting point. Make sure I document for myself how to instantiate a new container and make it feel like home:

This is working off of LXD installed with apt (not snap) on a WSL2 Ubuntu 18.04 instance. WSL installs 20.04 by default so to make this environment you have to install Ubuntu 18.04 from the Microsoft Store. Unfortunately, systemd must be running in order for lxd to install, but systemd is not running on WSL2 Linux. You can’t even just turn it on. There’s an external dependency here. I’m confident it will go away in time as Microsoft recently hired Lennart Poettering who created systemd. But until then you have to use (distrod)[https://github.com/nullpo-head/wsl-distrod]. On an already existing siting Linux host under WSL2, this turns on systemd:

curl -L -O "https://raw.githubusercontent.com/nullpo-head/wsl-distrod/main/install.sh"
chmod +x install.sh
sudo ./install.sh install

Okay, once this is done, LXD should install cleanly:

sudo apt install lxd
sudo lxd init

That init command is the way to set up LXD for the first time. It steps you through a wizard with recommended defaults. The reason to use Ubuntu 18.04 installed from apt (instead of installed from snap under Ubuntu 20.04) is so that you can just hit [Enter] through the entire wizard. Once that’s done you can use the “lxc” commands. Almost all further use of “lxd” as a command is over. All the creation and manipulation of instances of containers is accomplished through the lxc command.

lxc ls

You can also use “lxc list”. Either way, this is the beginning of your new container habits. If there’s stuff there then the general pattern is:

lxc stop ContainerName
lxc start ContainerName

If there’s no container there and you want to create a new one, the concept is “launch”. Ugh, can you believe it? Yet more mental gymnastics of word/meaning remapping for the container world.

lxc launch images:ubuntu/18.04 GlookingLass

This is the creation of a container instance of an image. The image itself is never saved locally as any sort of master image. It just becomes an immediately runnable instance by using it in an lxc start statement. But there’s a few things that ought to be done.

lxc config device add GlookingLass github disk source=/mnt/c/Users/mikle/github path=/home/ubuntu/github
lxc config device add GlookingLass dotssh disk source=/mnt/c/Users/mikle/.ssh/ path=/home/ubuntu/.ssh/
lxc config device add GlookingLass data disk source=/mnt/data path=/home/ubuntu/data

Those are the two locations from the WSL2 Linux “host” that get added through the lxc command. It’s also worth noting that on the host, this was done to make the data location available:

mkdir /mnt/data
sudo mount -t drvfs '\\EchidNAS\data' /home/ubuntu/data

NOTE: I learned on a following day that this line had to be added to my /etc/fstab to make it persistent.

sudo vim /etc/fstab

Added this line:

\\EchidNAS\data /mnt/data drvfs defaults 0 0

And so if this container is moved around, how these locations get established may vary. But so long as the containers are on my Windows laptop, these commands work. As an added bonus, I have this on the .bash_profile of the WSL2 Linux host so that containers can always have access to the WSL2 host’s nameserver in case I want Linux containers to use graphical apps through X-Server.

export DISPLAY=$(cat /etc/resolv.conf | grep nameserver | awk '{print $2}'):0
echo "export DISPLAY=${DISPLAY}" > ~/data/display.sh

And in the .bash_profile of the container:

source ~/py310/bin/activate
source ~/data/display.sh
. ~/.bash_prompt
cd ~/github

Oh, that reminds me. To get Python 10 installed and a virtualenv created:

sudo apt update
sudo apt install git
sudo apt install software-properties-common
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt install python3.10
sudo apt install python3.10-venv
python3.10 -m venv py310

This is close to the general container-building pattern I’ll be using maybe forever forward now. With this information in-hand I should go ahead and do experiments knowing I can just do it all again. Make the new patterns in my head. And then make a video where my actions are more practiced for the world. 1, 2, 3… 1?

At this time I will git clone my vim repo and from there, copy these files to home ~/

Oh! One more thing. Let’s get my current favorite gratuitous Linux prompt highlighting working. That’s what that .bash_prompt file is that’s being referred to in the .bash_profile file. Basically just grab it from here (https://github.com/bpeebles/bash_prompt.sh)[https://github.com/bpeebles/bash_prompt.sh] and save it as ~/.bash_prompt. Refer to it in .bash_profile as instructed and you’ll have a nifty prompt that shows your:

It’s a good time to remind myself how to see if systemd is running. This is useful on both the WSL2 Linux host machine to see whether you need to install distrod, or on the containers to assure yourself systemd is running for the next step. That’s the “ps” command.

Okay, so if you want to know if systemd is running, what you’re looking for is the name of the command running on pid 1. That’s “process ID 1”. In both Unix and Linux, everything running on your system is given an ID in the order it runs. By definition, the “init” task is the very first thing to run. The old name of the init task was init. So this is how we look at it:

ps 1

The “ps” command that stands for “process status” in Unix/Linux lists all hte running processes. The number 1 tells it to only list the data for the process with the ID 1. This is your init process. You’ll see in the COMMAND column there’s a lot of gobbledygook for the path and stuff. We can customize the output to just the command column, which gives its appreciation.

ps -o comm 1

This is good but it still shows the column header which is confusing and would mess up automations if you’re writing something that’s just supposed to pull back the name. And so we can suppress the headers:

ps --no-headers -o comm 1

And there we have it. That’s what’s necessary to see if we’re running systemd or not. I’ve got to get that into my head so I don’t struggle every time. The concept is that it’s just looking at ID 1 with the ps command. The rest is formatting.

Now I feel comfortable experimenting with my first container. Initially, it feels precious. But because you’re in script-land, everything is easily automateable so long as you keep good notes. And I am.

Everything I’ve done so far has really been for this next step.

Just do it without getting hung up on a video. Do it with a video after you’ve done it to a container or two. Hmmm. Snapshot a container before you do the work. What are these moves?

Get a service running: