[libvirt] [Question] capabilities.pidfile is left behind while starting and stopping libvirtd repeatly

[Martin Kletzander]

On Wed, Oct 08, 2014 at 04:07:33PM +0800, Wang Rui wrote:
>On 2014/10/2 17:55, Martin Kletzander wrote:
>> On Tue, Sep 30, 2014 at 10:26:21PM +0200, Guido Günther wrote:
>>> On Tue, Sep 30, 2014 at 04:47:14PM +0200, Martin Kletzander wrote:
>>>> On Tue, Sep 30, 2014 at 05:34:54PM +0800, Wang Yufei wrote:
>>>> >Hi, all
>>>> >
>>>> >I started and stopped libvirtd service repeatly with high frequency(1 per second), and found that the file capabilities.pidfile is left behind, as well as a qemu process. If I then restart libvirtd, qemu-kvm will fail to start as it's unable to flock capabilities.pidfile's fd.
>>>> >
>>>>
>>>> Have you tried current master?  Or at least -rc2?  It should already
>>>> be fixed there:
>>>>
>>>> commit 9e159b521dbf18c6da6976e54e29c8553f831eb6
>>>> Author: Guido Günther <agx at sigxcpu.org>
>>>> Date:   Thu Sep 25 10:30:58 2014 +0200
>>>>
>>>>    qemu: remove capabilities.monitor.sock when done
>>>>
>>>
>>> This one removes the monitor socket, not the pidfile since I didn't
>>> see that one lingering around in my tests.
>>> Cheers,
>>
>> Oh, sorry for that, my fault.  Well, should the daemon just kill the
>> process when it's dying in order to release the lock?  If you try
>> slower, we will properly remove the pidfile, won't we?
>
>Yes, the pidfile will be keep open and locked forever if this qemu process
>is alive. And it will be unlink if I shutdown libvitd daemon slower. But
>in this condition(started and stopped libvirtd service repeatly with high
>frequency) the pidfile is left behind. In fact libvirtd daemon is killed
>before qemu-kvm process and pidfile are cleaned up. Is it a problem?
>

Simple kill(getpid(), SIGTERM) was enough to find out this is exactly
what's happening.  I have a fix prepared for this, but when I tried
checking whether it fixes everything, I realized I can't find any
problem this causes.  And that's strange.  All domain capabilities
were in place even though I cleared them from the cache.

Is there any cause of this problem?  Does something not work then?
I just want to know to test it basically :)

Thanks for finding that out,
Martin
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20141009/aac9ad6d/attachment-0001.sig>