[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: systemd effectively mandatory now due to GNOME

On Thu, Oct 24, 2013 at 12:25:12PM -0500, Serge Hallyn wrote:
> Quoting Brian May (brian@microcomaustralia.com.au):
> > On 24 October 2013 11:09, Adam Borowski <kilobyte@angband.pl> wrote:

> > > * it breaks other users of cgroups.  I have not tested this personally
> > > (mostly because of the above point), but if I understand it right, it takes
> > > over the whole cgroups system, requiring anything that runs on the same
> > > kernel instance to beg it via dbus to perform required actions.

> > I have heard this said before, would like to have some official
> > confirmation if this is actually the case or not. cgroups are currently
> > hierarchical, I would have thought this would mean, at least in theory,
> > different programs could be responsible for different parts of
> > the hierarchy.

> It currently can't prevent you from just mounting the cgroupfs and
> working with it.  One of the justifications presented at plumbers for
> wanting to do this was that changes to a subtree you control can
> affect other tasks.  But it was agreed that that was actually only
> for realtime (?) cgroup and that it is a bug which must be fixed.

The upshot being, AIUI, that there is a legitimate need for a single process
on each system to have a complete view of the cgroups heirarchy; even if
most users don't need a fine-grained policy manager, we should design with
this in mind.  On systems using systemd as init, the plan is for PID 1 to be
the process that has this overview, and that's fine; the problem is the
tight coupling of logind to systemd init for this, rather than using a
standard interface that can be implemented by multiple providers of a cgroup
manager service.

And this is not just an issue because of people not wanting to use systemd
init, but also because systemd init *can't* run in a container.  So if you
want any of the other users of cgroups (such as lxc) to coexist with
systemd, there needs to be a common protocol for this.

Steve Langasek                   Give me a lever long enough and a Free OS
Debian Developer                   to set it on, and I can move the world.
Ubuntu Developer                                    http://www.debian.org/
slangasek@ubuntu.com                                     vorlon@debian.org

Attachment: signature.asc
Description: Digital signature

Reply to: