[Pacemaker] Make resources more important than others

[Dejan Muhamedagic]

Hi,

On Thu, Jun 02, 2011 at 08:44:46AM +0100, Luke Bigum wrote:
> Hi list,
>
> I have a conceptual question about making Pacemaker treat some resources  
> a lot more important than others. I'm afraid the answer is going to come  
> back "sorry you can't", but I just want to confirm.

You were (most probably) right :)

But it sounds interesting. Now, if java is not so important, why
do you run it in the cluster?

Thanks,

Dejan

> I have a simple 2 node cluster that runs two services (MySQL and a Java  
> daemon) on top of network attached storage that can float between both  
> nodes. CRM config looks a bit like:
>
> node node1
> node node2
> primitive lsb:mysql mysql
> primitive lsb:java java
> primitve lsb:storage storage
> colocation mysql_with_storage inf: mysql storage
> colocation java_with_storage inf: java storage
> order mysql_after_storage: storage:start mysql:start symmetrical=true
> order java_after_storage: storage:start java:start symmetrical=true
>
> I've got the interesting requirement that mysql is vastly more important  
> than the java resource. The java has to run on the same server as mysql.  
> Also, if mysql is stopped/unmanaged, the java should still be running on  
> what would be the correct node for mysql. I've mostly achieved this by  
> colocating the java and mysql to the underlying storage.
>
> It gets tricky when we start simulating hard failures. If we simulate a  
> hard error with mysql, the storage moves to another node, then mysql and  
> java, and everything's great. What I don't want is the opposite to  
> occur. I don't want any hard error with java to make the mysql move, as  
> I consider the mysql more important than java and I don't want to outage  
> mysql if the java has a problem. I'd love for the mysql to stay running  
> where it is and have an administrator come along and cleanup what's  
> wrong with the java.
>
> I guess I want to somehow describe the java resource as "not as  
> important" as mysql, and this is what I don't think is possible. I know  
> I'm talking about very edge cases by simulating hard errors (eg: monitor  
> return code 5), but it'd be nice to achieve.
>
> Any thoughts?
>
> Thanks in advance,
>
> -Luke
>
> -- 
> Luke Bigum
>
> Information Systems
> Luke.Bigum at lmax.com | http://www.lmax.com
> LMAX, Yellow Building, 1A Nicholas Road, London W11 4AN
>
>
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