[Pacemaker] Configuring a cluster for asymmetric operation

[Brad Jones]

David - thanks much.  I installed drbd, kept the skeleton (basically
empty) config file in place on server C, and it has stopped trying to
monitor.  I still don't quite understand how a server not running a
particular RA can monitor a service anyway?

But my immediate problem is indeed solved and I can keep symmetric "on."
--
Brad Jones
Brad at Jones.name
Mobile: 303-219-0795


On Fri, Jun 8, 2012 at 4:45 AM, David Coulson <david at davidcoulson.net> wrote:
> Pacemaker needs to be able to monitor on all nodes. Maybe if you install
> drbd on the third node but don't configure anything monitor will correctly
> report it is not running over there, and your location rules will stop it
> from even trying.
>
> Or just change the RA for DRBD to report not running instead of not
> installed - I had to do that in a few cases where the RA needed the config
> file to exist, but the file was on a filesystem managed by pacemaker. Seems
> to work ok, and isn't impacting the cluster at all.
>
>
> On 6/8/12 3:36 AM, Brad Jones wrote:
>>
>> I have a cluster with three nodes, A B and C.  A and B can basically
>> stand in for one another; they run a DRBD master/slave set, and
>> failure of A where most things run normally fires up services on B.
>>
>> C helps arbitrate quorum and runs Stonith plugins.  I've written
>> location rules to prohibit most of the production services from
>> running on node C.
>>
>> Problem is, the DRBD RA tries to monitor on node C, even though DRBD
>> isn't even installed.  (It fails, helpfully, "not installed.")  I'm
>> stuck with a slowly-incrementing failcount on C.
>>
>> When I give all services a default location rule and set
>> symmetric-cluster="false", some of the resources stay running on A but
>> most of the important ones stop.
>>
>> This was raised back in 2010 here:
>> <http://oss.clusterlabs.org/pipermail/pacemaker/2010-April/005873.html>
>> but I can't find much more about this issue on the web and there's
>> only passing mention of it in the Pacemaker documentation.
>>
>> Bottom line: What's required to correctly configure a cluster with
>> symmetric-cluster set to false?
>>
>> FYI I'm on pacemaker 1.1.6, heartbeat 3.0.5, on Ubuntu 10.04.
>>
>> Thanks!  Brad
>> --
>> Brad Jones
>> Brad at Jones.name
>> Mobile: 303-219-0795
>>
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