SystemD in a Jail

[unitrunker]

This is a serious post so serious replies only please.

I'd like to run a Linux userland inside a jail. Nothing new there. The more popular Linux distros use SystemD. What would it take to run a SystemD userland inside a jail?

My guesses are:

1. Linuxulator adds / extends its API to support SystemD.
2. Substitute a fake SystemD that makes userland happy.
3. A combination of the above.

One such API is systemd-nspawn(1).

The goal is a happy path that satisfies the most common use cases for compatibility. This may be a pipe dream where running bhyve inside a jail is a much better (but more resource taxing) solution.

 

[badbrain]

What is the specific distro you want to use inside a jail? ShellUser has a tutorial to install devuan inside jail.

 

[unitrunker]

What is the specific distro you want to use inside a jail?

RH or CentOS or Ubuntu

 

[Alexander Huemeyer]

Are u sure u need systemd? Also in docker-containers of your listed distros normaly no systemd is enabled.

 

[badbrain]

Are u sure u need systemd? Also in docker-containers of your listed distros normaly no systemd is enabled.

For older versions of them, yes. For recent versions of them, no. They're now all systemd based.

 

[Alexander Huemeyer]

For older versions of them, yes. For recent versions of them, no. They're now all systemd based.

They use systemd as init-system, but u can run all server tasks without systemd. U dont need an init-system in a jail.

 

[badbrain]

They use systemd as init-system, but u can run all server tasks without systemd. U dont need an init-system in a jail.

I don't think it's that simple. But I could be wrong.

 

[trasz@]

From what I can see, at least with Ubuntu Bionic the `service` command works just fine without systemd, so if you want things to get started automatically it should be a matter of a trivial shell script to run as init for the Linux jail.