Bug#803013: systemd should not destroy application created cgroups

[Julian Andres Klode]

On Fri, Nov 13, 2015 at 12:50:57PM +0100, Julian Andres Klode wrote:
> On Fri, Nov 13, 2015 at 11:36:30AM +1100, paul.szabo at sydney.edu.au wrote:
> > Progress? For my efforts upstream, I got the comment:
> > 
> > > Sorry, but systemd implements a single-writer cgroup logic (as
> > > requested by the kernel maintainers), and hence takes possesion of the
> > > whole tree. ...
> > 
> > I observe it only uses the /sys/fs/cgroup/systemd tree.
> > (I wonder about the "req by kernel" comment.)
> 
> See the end of the email.

Also:
http://thread.gmane.org/gmane.linux.kernel.cgroups/6638


> 
> > 
> > > ... If you want your own cgroup tree to manage, use the "Delegate=yes"
> > > feature in a service or scope, but otherwise systemd is in exclusive
> > > control.
> > 
> > Do we have that? Can we have it everywhere? Can we have it by default,
> > should not it be so?
> 
> No. You set Delegate=yes for the unit which manages its own cgroups
> hierarchy beneath the one designated by systemd.

This is also only a mid-term workaround, and will be dropped longer
term, AFAICT from: https://lwn.net/Articles/556112/

Because the kernel maintainer *really* wants a single writer.

-- 
Julian Andres Klode  - Debian Developer, Ubuntu Member

See http://wiki.debian.org/JulianAndresKlode and http://jak-linux.org/.

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