[Pacemaker] globally-unique clone question

[Joe Armstrong]

> -----Original Message-----
> From: Infos E-Blokos [mailto:infos at e-blokos.com]
> Sent: Thursday, May 21, 2009 9:16 AM
> To: pacemaker at clusterlabs.org
> Subject: Re: [Pacemaker] globally-unique clone question
> 
> 
> ----- Original Message -----
> From: "Eliot Gable" <egable at broadvox.net>
> To: "pacemaker at oss.clusterlabs.org" <pacemaker at clusterlabs.org>;
> "JoeArmstrong" <jarmstrong at postpath.com>
> Sent: Thursday, May 21, 2009 11:39 AM
> Subject: Re: [Pacemaker] globally-unique clone question
> 
> 
> > The typical usage in this case would be to make all mail servers
> serve all
> > domains (virtual domain support) and then run N instances across
> those N
> > servers. Then there is no per-server unique information to deal with.
> Then
> > you can run, for example, load sharing between the nodes using
> iptables
> > CLUSTERIP (since all nodes would then be serving the same data) and
> put a
> > constraint in the CIB that says that if the clone fails on a node,
> pull
> > that node from the load-sharing config by stopping or moving away
> your
> > load-sharing resource. At least, that's how I would do it.
> >
> >
> > Eliot Gable
> > Senior Engineer
> > 1228 Euclid Ave, Suite 390
> > Cleveland, OH 44115
> >
> > Direct: 216-373-4808
> > Fax: 216-373-4657
> > egable at broadvox.net
> >
> >
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> >
> > -----Original Message-----
> > From: Joe Armstrong [mailto:jarmstrong at postpath.com]
> > Sent: Thursday, May 21, 2009 11:04 AM
> > To: pacemaker at oss.clusterlabs.org
> > Subject: [Pacemaker] globally-unique clone question
> >
> > Hi All,
> >
> > I am a little confused about globally-unique clones, since there can
> be no
> > instance attributes for a clone how do you tell each clone that it is
> > unique ?
> >
> > My use case is that we need to run N instances of a mail server, each
> mail
> > server is unique in that it serves a specific domain, two mail server
> can
> > never run on the same host.  In order to provide HA we need to tell
> the
> > mail server instance what domain to serve (or what filesystem to
> mount in
> > order to get the right data/config).
> >
> > I was thinking that using globally-unique clones would be the way to
> > manage this (it makes the mutual exclusion rule easy: clone-node-
> max=1)
> > but I don't see how to make each instance unique.
> >
> > ... then again I could be mis-using the concept...
> >
> > Thanks for any pointers.
> >
> > Joe
> >
> 
> 
> I agree, the same for apache and postgresql with DRBD
> 

Unfortunately this is not possible due to the underlying database the mail server uses - but thanks for the idea anyway.

So back to the original problem - am I mis-using the globally-unique clone concept ?

Thanks.

Joe