Re: The "Unix Philosophy 2020" document

From: Alex Suykov <alex.suykov_at_gmail.com>
Date: Sun, 29 Dec 2019 18:07:39 +0200

Sat, Dec 28, 2019 at 06:41:56PM +0100, Oliver Schad wrote:

> > The reason I think it's mostly useless is because the only use case
> > for cgroup supervision is supervising double-forking daemons, which
> > is not a very smart thing to do. A much better approach is to get rid
> > of double-forking and then just directly supervise the resulting long
> > running process.
> > I can't think of any other cases where it would be useful.
>
> I definitly have to correct you: cgroups are *NOT* designed to catch
> wild forking processes. This is just a side-effect ot them.

Er, that whole quoted part, including the last sentence, is about using
cgroups to supervise processes. Not about the use of cgroups in general.
I can't think of any other use cases where cgroup supervision would be
useful, other than for double-forking daemons.

Also, wrt process supervision, calling it a side effect is bit misleading.
The interfaces are not really made for that kind of use at all. Strictly
speaking, anything doing kill `cat .../cgroup.procs` is racy and unreliable.
Including that runcg tool that I wrote. In practice, the race is pretty
much irrelevant, but it's still there, inherent to the interfaces.
Received on Sun Dec 29 2019 - 16:07:39 UTC