[systemd-devel] Feedback sought: can we drop cgroupv1 support soon?

[Lennart Poettering]

On Do, 21.07.22 11:55, Christian Brauner (brauner at kernel.org) wrote:

> In general, I wouldn't mind dropping cgroup1 support in the future.
>
> The only thing I immediately kept thinking about is what happens to
> workloads that have a v1 cgroup layout on the host possibly with an
> older systemd running container workloads using a newer distro with a
> systemd version without cgroup1 support.
>
> Think Ubuntu 18.04 host running a really new Ubuntu LTS that has a
> version of systemd with cgroup1 support already dropped. People do
> actually do stuff like that. Stéphane and Serge might know more about
> actual use-cases in that area.

The question is though how much can we get away with at that
front. i.e. I think we can all agree that if you attempt to run an
extremely new container on an extremely old host is something we
really don't have to support, once the age difference is beyond some
boundary. The question is at what that boundary is.

Much the same way as we have a baseline on kernel versions systemd
supports (currently 3.15, soon 4.5), we probably should start to
define a baseline of what to expect from a container manager.

Lennart

--
Lennart Poettering, Berlin