[lxc-users] zombie process blocks stopping of container

[Stéphane Graber]

On Tue, Jun 03, 2014 at 04:42:15PM +0200, Tamas Papp wrote:
> 
> On 06/03/2014 04:35 PM, Stéphane Graber wrote:
> >On Tue, Jun 03, 2014 at 04:23:14PM +0200, Tamas Papp wrote:
> >>hi All,
> >>
> >>  4489 ?        Ss     0:00 lxc-start -n fisheye1
> >>  4576 ?        Ss     0:01  \_ [init]
> >>25055 ?        Zl   2451:47      \_ [java] <defunct>
> >>
> >>
> >>The container cannot be stopped.
> >>ii  lxc 1.0.3-0ubuntu3                      amd64        Linux
> >>Containers userspace tools
> >>
> >>Linux v306 3.13.0-27-generic #50-Ubuntu SMP Thu May 15 18:06:16 UTC 2014
> >>x86_64 x86_64 x86_64 GNU/Linux
> >>
> >>
> >>What can I do to it?
> >>
> >>10x
> >>tamas
> >lxc-stop -n fisheye1 -k
> >
> >Unless you have a kernel bug, this should still work. The fact that java
> >is marked as zombie usually means that init didn't process the SIGCHLD
> >but that shouldn't prevent you from killing init itself which will
> >cleanup any child in the process.
> 
> FYI, the java process got zombie after a pkill (not by lxc-stop).
> I was not able to kill init, but lxc-start.
> 
> 
>  4576 ?        Ss     0:01 [init]
> 25055 ?        Zl   2451:47  \_ [java] <defunct>
> 
> 
> 
>        -k,--kill
>               Rather than requesting a clean shutdown of the
> container, explicitly kill all tasks in the container. This is the
> legacy lxc-stop behavior.
> 
>        --nokill
>               Only request a clean shutdown, do not kill the
> container tasks if the clean shutdown fails.
> 
> 
> My understanding is that lxc-stop should work the  same way as
> 'lxc-stop -k', am I wrong?

lxc-stop will send SIGPWR (or the equivalent signal) to the container,
wait 30s then SIGKILL init. lxc-stop -k will skip the SIGPWR step,
lxc-stop --nokill will skip the SIGKILL step.

It's pretty odd that init after a kill -9 is still marked running... I'd
have expected it to either go away or get stuck in D state if
something's really wrong...

Do you see anything relevant in the kernel log?

> 
> Thanks,
> tamas
> 
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-- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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