[libvirt] virtlockd max_clients limitation

Michal Privoznik mprivozn at redhat.com
Mon Aug 19 06:08:52 UTC 2013


On 18.08.2013 16:46, David Weber wrote:
> Hi,
> 
> we recently ran into a problem when trying to start more than 20 guests if 
> direct locking with virtlockd was enabled. The error message locked like this:
> # start test7
> error: Failed to start domain test7
> error: Cannot recv data: Connection reset by peer
> 
> Our research indicated there is a max_clients parameter set in src/locking/lock_daemon.c which causes the limitation.
> Simply increasing this number works as a workaround.
> 
> I don't have a deep understanding of the code, so I don't know if there is a 
> bug and the connection should be dropped after the lock is set or if 
> max_clients really is the way to go. If the latter I guess max_clients should 
> be configurable like in virtlockd or at least be higher than 20 :)
> 
> Libvirt version 1.1.1
> 
> Cheers,
> David
> 
>>From 5187231a973a9956723683c7fad14c8bb3dfcac2 Mon Sep 17 00:00:00 2001
> From: David Weber <wb at munzinger.de>
> Date: Sun, 18 Aug 2013 16:16:36 +0200
> Subject: [PATCH] Increase virtlockd max clients
> 
> ---
>  src/locking/lock_daemon.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/locking/lock_daemon.c b/src/locking/lock_daemon.c
> index c4c1727..d96d0fc 100644
> --- a/src/locking/lock_daemon.c
> +++ b/src/locking/lock_daemon.c
>                     virLockDaemonNew(bool privileged)
>          return NULL;
>      }
>  
> -    if (!(lockd->srv = virNetServerNew(1, 1, 0, 20,
> +    if (!(lockd->srv = virNetServerNew(1, 1, 0, 100,
>                                         -1, 0,
>                                         false, NULL,
>                                         virLockDaemonClientNew,
> 

This will work for a while until somebody tries starting up more than
100 libvirtds. Maybe it's time for /etc/libvirt/virtlockd.conf introduction.

Michal




More information about the libvir-list mailing list