[Mageia-dev] systemd vs dm

[Colin Guthrie]

'Twas brillig, and Dick Gevers at 17/09/11 11:40 did gyre and gimble:
> On Sat, 17 Sep 2011 11:16:57 +0100, Colin Guthrie wrote about Re:
> [Mageia-dev] systemd vs dm:
> 
>> Well that's slightly disturbing. It seems that rsyslog was started but
>> not by systemd.
>>
>> Can do do some kind of pstree type analysis (perhaps also using cgroups
>> stuff) to work out what process actually started rsyslog?
> 
> pstree is not quite unequivocal, because it shows systemd at the top of
> every running process, even those surely not started by systemd but e.g. by
> the current user.

Yeah that's expected. Everything is a child of pid 1 really, but what
would be interesting is if rsyslog is a direct child of pid 1 or if
there are any other processes in between, but I guess not.

> But on the other hand systemd has PID 1 so it's reasonable to assume
> everything stems from it.

Yup.

> Although when I do lsof |grep rsys |grep syst it returns nothing, so
> perhaps that means rsyslog was not started by systemd: we'd have to compare
> with a system where systemctl status rsyslog.service gives a better result.

Nah I wouldn't expect rsyslog to know anything specifically about
systemd, so this would be the expected output.

> "lsof |grep cgrou" returns only one line:
> 
> systemd       1             root    6r      DIR               0,18
> 0        193 /sys/fs/cgroup/systemd/system
> 
> I hope this gives some clues.

Sadly not.

What would be useful is to find the pid of rsyslog (mine is 1505), and
then do:
[root at jimmy ~]# cat /proc/1505/cgroup
8:blkio:/
7:net_cls:/
6:freezer:/
5:devices:/
4:memory:/
3:cpuacct,cpu:/system/rsyslog.service
2:cpuset:/
1:name=systemd:/system/rsyslog.service


If it looks similar to mine then it has been started by systemd but it's
somehow "lost" that info.


I wonder, do you do anything special with either /var /var/run or /run
directories? Are they on separate partitions or anything?

Col




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Colin Guthrie
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http://colin.guthr.ie/

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