[Pacemaker] globally-unique clone question

[Infos E-Blokos]

----- 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 


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