[ClusterLabs] location constraint does not move promoted resource ?

Andrei Borzenkov arvidjaar at gmail.com
Mon Jul 3 12:22:37 EDT 2023


On 03.07.2023 18:07, Ken Gaillot wrote:
> On Mon, 2023-07-03 at 12:20 +0200, lejeczek via Users wrote:
>>
>> On 03/07/2023 11:16, Andrei Borzenkov wrote:
>>> On 03.07.2023 12:05, lejeczek via Users wrote:
>>>> Hi guys.
>>>>
>>>> I have pgsql with I constrain like so:
>>>>
>>>> -> $ pcs constraint location PGSQL-clone rule role=Promoted
>>>> score=-1000 gateway-link ne 1
>>>>
>>>> and I have a few more location constraints with that
>>>> ethmonitor & those work, but this one does not seem to.
>>>> When contraint is created cluster is silent, no errors nor
>>>> warning, but relocation does not take place.
>>>> I can move promoted resource manually just fine, to that
>>>> node where 'location' should move it.
>>>>
>>>
>>> Instance to promote is selected according to promotion
>>> scores which are normally set by resource agent.
>>> Documentation implies that standard location constraints
>>> are also taken in account, but there is no explanation how
>>> promotion scores interoperate with location scores. It is
>>> possible that promotion score in this case takes precedence.
>> It seems to have kicked in with score=-10000 but..
>> that was me just guessing.
>> Indeed it would be great to know how those are calculated,
>> in a way which would' be admin friendly or just obvious.
>>
>> thanks, L.
> 
> It's a longstanding goal to have some sort of tool for explaining how
> scores interact in a given situation. However it's a challenging
> problem and there's never enough time ...
> 
> Basically, all scores are added together for each node, and the node
> with the highest score runs the resource, subject to any placement
> strategy configured. These mainly include stickiness, location
> constraints, colocation constraints, and node health. Nodes may be

And you omitted the promotion scores which was the main question.

> eliminated from consideration by resource migration thresholds,
> standby/maintenance mode, etc.



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