systemd in WSLv2

I am using archlinux in my WSL for the last two (2) years and the whole experience is quite smooth. I wanted to test native docker will run within WSL and not with the windows docker/container service, so I installed docker. My main purpose is building packages so (for now) I do not need networking/routes or anything else.

WSL

ebal@myworklaptop:~$ uname -a
Linux myworklaptop 4.19.128-microsoft-standard #1 SMP Tue Jun 23 12:58:10 UTC 2020 x86_64 GNU/Linux

ebal@myworklaptop:~$ cat /etc/os-release
NAME="Arch Linux"
PRETTY_NAME="Arch Linux"
ID=arch
BUILD_ID=rolling
ANSI_COLOR="38;2;23;147;209"
HOME_URL="https://www.archlinux.org/"
DOCUMENTATION_URL="https://wiki.archlinux.org/"
SUPPORT_URL="https://bbs.archlinux.org/"
BUG_REPORT_URL="https://bugs.archlinux.org/"
LOGO=archlinux

Docker Install

$ sudo pacman -S docker

$ sudo pacman -Q docker
docker 1:20.10.6-1

$ sudo dockerd -v
Docker version 20.10.6, build 8728dd246c

Run docker

sudo dockerd -D

-D is for debug

and now pull an alpine image

ebal@myworklaptop:~$ docker images
REPOSITORY   TAG       IMAGE ID   CREATED   SIZE

ebal@myworklaptop:~$ docker pull alpine:latest
latest: Pulling from library/alpine
540db60ca938: Pull complete
Digest: sha256:69e70a79f2d41ab5d637de98c1e0b055206ba40a8145e7bddb55ccc04e13cf8f
Status: Downloaded newer image for alpine:latest
docker.io/library/alpine:latest

ebal@myworklaptop:~$ docker images
REPOSITORY   TAG       IMAGE ID       CREATED       SIZE
alpine       latest    6dbb9cc54074   2 weeks ago   5.61MB

Test alpine image

docker run -ti alpine:latest ash

perform a simple update

# apk update

fetch https://dl-cdn.alpinelinux.org/alpine/v3.13/main/x86_64/APKINDEX.tar.gz
fetch https://dl-cdn.alpinelinux.org/alpine/v3.13/community/x86_64/APKINDEX.tar.gz
v3.13.5-71-gfcabe3349a [https://dl-cdn.alpinelinux.org/alpine/v3.13/main]
v3.13.5-65-g28e7396caa [https://dl-cdn.alpinelinux.org/alpine/v3.13/community]

OK: 13887 distinct packages available

okay, seems that it is working.

Genie Systemd

as many already know, we can not run systemd inside WSL, at least not by default. So here comes genie !

A quick way into a systemd “bottle” for WSL

WSLv2 ONLY.

wsl.exe -l -v

  NAME            STATE           VERSION
* Archlinux       Running         2
  Ubuntu-20.04    Stopped         1

It will work on my arch.

Install Genie

genie comes by default with an archlinux artifact from github

curl -sLO https://github.com/arkane-systems/genie/releases/download/v1.40/genie-systemd-1.40-1-x86_64.pkg.tar.zst

sudo pacman -U genie-systemd-1.40-1-x86_64.pkg.tar.zst

$ pacman -Q genie-systemd
genie-systemd 1.40-1

daemonize

Genie has a dependency of daemonize.

In Archlinux, you can find the latest version of daemonize here:

https://gitlab.com/archlinux_build/daemonize

$ sudo pacman -U daemonize-1.7.8-1-x86_64.pkg.tar.zst

loading packages...
resolving dependencies...
looking for conflicting packages...

Package (1)  New Version  Net Change
daemonize    1.7.8-1        0.03 MiB
Total Installed Size:  0.03 MiB

:: Proceed with installation? [Y/n] y

$ pacman -Q daemonize
daemonize 1.7.8-1

Is genie running ?

We can start as-root genie with a new shell:

# genie --version
1.40

# genie -s
Waiting for systemd....!

# genie -r
running

okay !

Windows Terminal

In order to use systemd-genie by default, we need to run our WSL Archlinux with an initial command.

I use aka.ms/terminal to start/open my WSLv2 Archlinux so I had to edit the “Command Line” Option to this:

wsl.exe -d Archlinux genie -s

You can also verify that your WSL distro is down, with this

wsl.exe --shutdown

then fire up a new WSL distro!

Systemd Service

you can enable & start docker service unit,

$ sudo systemctl enable docker

$ sudo systemctl start  docker

so next time will auto-start:

$ docker images
REPOSITORY   TAG       IMAGE ID       CREATED       SIZE
alpine       latest    6dbb9cc54074   2 weeks ago   5.61MB

systemd

$ ps -e fuwwww | grep -i systemd
root           1  0.1  0.2  21096 10748 ?        Ss   14:27   0:00 systemd
root          29  0.0  0.2  30472 11168 ?        Ss   14:27   0:00 /usr/lib/systemd/systemd-journald
root          38  0.0  0.1  25672  7684 ?        Ss   14:27   0:00 /usr/lib/systemd/systemd-udevd
dbus          63  0.0  0.1  12052  5736 ?        Ss   14:27   0:00 /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only
root          65  0.0  0.1  14600  7224 ?        Ss   14:27   0:00 /usr/lib/systemd/systemd-logind
root         211  0.0  0.1  14176  6872 ?        Ss   14:27   0:00 /usr/lib/systemd/systemd-machined
ebal         312  0.0  0.0   3164   808 pts/1    S+   14:30   0:00  _ grep -i systemd
ebal         215  0.0  0.2  16036  8956 ?        Ss   14:27   0:00 /usr/lib/systemd/systemd --user

$ systemctl status docker
* docker.service - Docker Application Container Engine
     Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
     Active: active (running) since Sat 2021-05-01 14:27:12 EEST; 3min 22s ago
TriggeredBy: * docker.socket
       Docs: https://docs.docker.com
   Main PID: 64 (dockerd)
      Tasks: 17 (limit: 4715)
     Memory: 167.9M
     CGroup: /system.slice/docker.service
             |-64 /usr/bin/dockerd -H fd://
             `-80 containerd --config /var/run/docker/containerd/containerd.toml --log-level info

May 01 14:27:12 myworklaptop-wsl systemd[1]: Started Docker Application Container Engine.
May 01 14:27:12 myworklaptop-wsl dockerd[64]: time="2021-05-01T14:27:12.303580300+03:00" level=info msg="AP>

that’s it !