Support running systemd in the containers

[DemiMarie]

Description

Containers can be used to not only run individual applications, but also to run complete operating systems. For instance, one can run all of NixOS inside a container.

However, modern Linux distributions often use systemd, which doesn’t work in gVisor. It would be much nicer if systemd did work in gVisor.

Is this feature related to a specific bug?

No response

Do you have a specific solution in mind?

Implement enough Linux kernel compatibility to make systemd pass its test suite.

[milantracy]

it is something we aim to implement, i believe it is not urgent as of today.

please feel free to send PRs if you already have the patch, otherwise, we can revisit this later this year