[ClusterLabs] Antw: Re: When the DC crmd is frozen, cluster decisions are delayed infinitely

[Jehan-Guillaume de Rorthais]

On Thu, 8 Sep 2016 08:58:15 +0000
Shermal Fernando <shermalfe at millenniumit.com> wrote:

> Hi Jehan-Guillaume,
> 
> Does this means watchdog will serf-terminate the machine when the crm daemon
> is frozen?

This means that if the machine is under such a load that PAcemaker is not able
to feed the watchdog, the watchdog will fence the machine itself.

> -----Original Message-----
> From: Jehan-Guillaume de Rorthais [mailto:jgdr at dalibo.com] 
> Sent: Thursday, September 08, 2016 12:52 PM
> To: Digimer
> Cc: Cluster Labs - All topics related to open-source clustering welcomed
> Subject: Re: [ClusterLabs] Antw: Re: When the DC crmd is frozen, cluster
> decisions are delayed infinitely
> 
> On Thu, 8 Sep 2016 15:55:50 +0900
> Digimer <lists at alteeve.ca> wrote:
> 
> > On 08/09/16 03:47 PM, Ulrich Windl wrote:
> > >>>> Shermal Fernando <shermalfe at millenniumit.com> schrieb am 
> > >>>> 08.09.2016 um
> > >>>> 06:41 in
> > > Nachricht
> > > <8CE6E8D87F896546B9C65ED80D30A4336578CB4A at LG-SPMB-MBX02.lseg.stockex.local>:
> > >> The whole cluster will fail if the DC (crm daemon) is frozen due to 
> > >> CPU starvation or hanging while trying to perform a IO operation.
> > >> Please share some thoughts on this issue.
> > > 
> > > What is "the whole cluster will fail"? If the DC times out, some 
> > > recovery will take place.
> > 
> > Yup. The starved node should be declared lost by corosync, the 
> > remaining nodes reform and if they're still quorate, the hung node 
> > should be fenced. Recovery occur and life goes on.
> 
> +1
> 
> And fencing might either come from outside, or just from the server itself
> using watchdog.