[ClusterLabs] Antw: Re: Antw: Unexpected Resource movement after failover

[Nikhil Utane]

I had set resource utilization to 1. Even then it scheduled 2 resources.
Doesn't it honor utilization resources if it doesn't find a free node?

-Nikhil

On Mon, Oct 24, 2016 at 4:43 PM, Vladislav Bogdanov <bubble at hoster-ok.com>
wrote:

> 24.10.2016 14:04, Nikhil Utane wrote:
>
>> That is what happened here :(.
>> When 2 nodes went down, two resources got scheduled on single node.
>> Isn't there any way to stop this from happening. Colocation constraint
>> is not helping.
>>
>
> If it is ok to have some instances not running in such outage cases, you
> can limit them to 1-per-node with utilization attributes (as was suggested
> earlier). Then, when nodes return, resource instances will return with (and
> on!) them.
>
>
>
>> -Regards
>> Nikhil
>>
>> On Sat, Oct 22, 2016 at 12:57 AM, Vladislav Bogdanov
>> <bubble at hoster-ok.com <mailto:bubble at hoster-ok.com>> wrote:
>>
>>     21.10.2016 19:34, Andrei Borzenkov wrote:
>>
>>         14.10.2016 10:39, Vladislav Bogdanov пишет:
>>
>>
>>             use of utilization (balanced strategy) has one caveat:
>>             resources are
>>             not moved just because of utilization of one node is less,
>>             when nodes
>>             have the same allocation score for the resource. So, after the
>>             simultaneus outage of two nodes in a 5-node cluster, it may
>>             appear
>>             that one node runs two resources and two recovered nodes run
>>             nothing.
>>
>>
>>         I call this a feature. Every resource move potentially means
>> service
>>         outage, so it should not happen without explicit action.
>>
>>
>>     In a case I describe that moves could be easily prevented by using
>>     stickiness (it increases allocation score on a current node).
>>     The issue is that it is impossible to "re-balance" resources in
>>     time-frames when stickiness is zero (over-night maintenance window).
>>
>>
>>
>>             Original 'utilization' strategy only limits resource
>>             placement, it is
>>             not considered when choosing a node for a resource.
>>
>>
>>
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