[Pacemaker] Migrating resources on custom conditions

[Vladislav Bogdanov]

21.02.2014 02:58, Andrew Beekhof wrote:
> 
> On 20 Feb 2014, at 7:34 pm, Dan Markhasin <minimizer at gmail.com> wrote:
> 
>> Hi,
>>
>> I am wondering if it is possible to configure complex/custom migration rules, so resources would migrate in case there is a problem with the current node it is running on.
>>
>> i.e.
>>
>> If the node has a bad disk, or high load, the resource should be migrated to a different node.
> 
> If you write a resource agent that monitors any or all of the above conditions and add it to the cluster as an unmanaged clone resource, then you can colocate things with it.
> At the point the disk goes bad, the resource appears to have stopped and the real resources will be moved somewhere else.

It could be nice feature to have kind of general SLA concept (it could
be very similar to the utilization one from the resource configuration
perspective), so resources try to move or live migrate out of nodes
which have SLA attributes below the configured threshold. That SLA
attributes should probably go to the status section (to not trigger
transition aborts on attribute updates) and be managed both internally
by pacemaker (expansion to the recent "node-load" concept) and by
resource agents (like Health-* as noted by Frank).

Pacemaker already has (almost?) all pieces of code to do that ('rule'
and 'score-attribute'), but in my taste it is still not enough general
in contrast to 'utilization' feature.

Best,
Vladislav

> 
>> I didn't find any examples for such custom rules in the documentation. Is it possible ?
>>
>> Thanks,
>> Dan
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> 
> 
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