Re: systemd and server use
On Fri, Sep 26, 2014 at 01:02:16PM -0400, The Wanderer wrote:
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> On 09/26/2014 at 12:26 PM, Steve Litt wrote:
>
> > On Fri, 26 Sep 2014 12:03:57 +0200 Martin Steigerwald
> > <Martin@lichtvoll.de> wrote:
>
> >> Actually systemd has quite some features which benefits server
> >> use.
> >>
> >> For example:
> >>
> >> 1) It groups services and shell sessions into process control
> >> cgroups and shields them against each other CPU usage wise.
>
> >> 2) It is really good at catching the PIDs of the services it
> >> runs, no matter what funny things they do like double forking. So
> >> it exactly stops these PIDs and no others.
>
> >> 3) Compare systemctl service status with /etc/init.d/service
> >> status. Its obvious that the systemctl output is way more useful
> >> to administrators.
> >>
> >>
> >> Can these be implemented elsewhere? I´d say yet for 1. Yet 2 and
> >> partly 3 I think is the core of an init system.
>
> Agreed - definitely 2, maybe / maybe-not 3, and definitely not 1.
Start an xterm.
$ bash
$ ulimit -u 2000
$ :(){ :|:& };: # THIS IS A FORK BOMB.
watch it run 2000 processes and then start erroring.
open another xterm, verify that they are real.
Close the first xterm.
Verify that the processes are gone.
ulimit can also be applied in PAM at login time for users, or for specific
daemons.
-dsr-
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