[Pacemaker] Configuring 3rd Node as Quorum Node in 2 Node Cluster

Andrew Martin amartin at xes-inc.com
Thu Feb 23 09:59:26 EST 2012


I set up the 3rd node ("quorum") yesterday by only installing heartbeat, not pacemaker. Is pacemaker necessary as well? I commented out the following lines in its ha.cf since it is always going to be running in standby: 

autojoin none 
mcast eth0 239.0.0.43 694 1 0 
bcast eth0 
warntime 5 
deadtime 15 
initdead 60 
keepalive 2 
node node1 
node node2 
node quorum 
#crm respawn 
#respawn hacluster /usr/lib/heartbeat/dopd 
#apiauth dopd gid=haclient uid=hacluster 


Since this quorum node only has a single ethernet interface, can it be used for both the mcast and bcast parameters? How are both the multicast and broadcast pathways used for node communication? After saving these parameters and reloading heartbeat on all nodes, the "quorum" node is listed as offline in the cluster. Is there something missing in my configuration that is preventing it from communicating with the rest of the cluster? 



Also, another more general question about the failover - node1 and node2 are each connected to the shared network over br0 and connected directly to each other with a crossover cable over br1: 
-------------------- ---------- 
| Shared Network |------| quorum | 
-------------------- ---------- 
| 
br0 / \ br0 
/ \ 
--------- --------- 
| node1 | --------- | node2 | 
--------- br1 --------- 


The corresponding configuration in ha.cf is 

autojoin none 
mcast br0 239.0.0.43 694 1 0 
bcast br1 
warntime 5 
.... 


If br0 to one of the nodes were to be cut when the "quorum" node was down, would they still be able to communicate over br1 (e.g. to maintain quorum between themselves and fail over to the other node that still has an active br0)? 


Thanks, 


Andrew 
----- Original Message -----

From: "Andreas Kurz" <andreas at hastexo.com> 
To: pacemaker at oss.clusterlabs.org 
Sent: Monday, January 23, 2012 1:53:27 PM 
Subject: Re: [Pacemaker] Configuring 3rd Node as Quorum Node in 2 Node Cluster 

On 01/23/2012 03:36 PM, Andrew Martin wrote: 
> I think I will configure the 3rd (quorum) node in standby mode. In the 
> near future I am looking into setting up 2 additional clusters (each of 
> these are also 2-node clusters) and would like to use this same server 
> as the quorum node for those clusters as well. Is this possible? If so, 
> how do I have to configure heartbeat (or multiple instances of 
> heartbeat) to join multiple clusters at once and act as the quorum node 
> in each? 

No, multiple heartbeat instances per node are not supported ... but why 
not creating minimal VM instances ... though not to minimal, as you have 
a good chance that theses standby instances become DC role. 

Regards, 
Andreas 

-- 
Need help with Pacemaker? 
http://www.hastexo.com/now 

> 
> Thanks, 
> 
> Andrew 
> 
> ------------------------------------------------------------------------ 
> *From: *"Andreas Kurz" <andreas at hastexo.com> 
> *To: *pacemaker at oss.clusterlabs.org 
> *Sent: *Friday, January 13, 2012 6:35:48 AM 
> *Subject: *Re: [Pacemaker] Configuring 3rd Node as Quorum Node in 2 
> Node Cluster 
> 
> On 01/13/2012 12:32 PM, Ivan Savčić | Epix wrote: 
>> On 1/11/2012 8:28 AM, Florian Haas wrote: 
>>> Another option would be to permanently run the 3rd node in standby mode. 
>> 
>> Just wondering, wouldn't the standby mode prevent that node from 
>> performing the fencing actions? Also, can it act as DC then? 
> 
> It would run no resources (including stonith resources) but can be the DC. 
> 
> Another option for running a "pure" quorum node would be to only start 
> CCM but not pacemaker ... though that setup looks quite strange e.g. in 
> crm_mon output .... 
> 
> Regards, 
> Andreas 
> 
> -- 
> Need help with Pacemaker? 
> http://www.hastexo.com/now 
> 
>> 
>> Thanks, 
>> Ivan 
>> 
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