[ClusterLabs] Maintenance mode status in CIB

[Strahil Nikolov]

Also, it's worth mentioning that you can set the whole cluster in global maintenance and power off the stack on all nodes without affecting your resources.
I'm not sure if that is ever possible in node maintenance.

Best Regards,
Strahil Nikolov






В вторник, 13 октомври 2020 г., 12:49:38 Гринуич+3, Digimer <lists at alteeve.ca> написа: 





On 2020-10-13 5:41 a.m., Jehan-Guillaume de Rorthais wrote:
> On Tue, 13 Oct 2020 04:48:04 -0400
> Digimer <lists at alteeve.ca> wrote:
> 
>> On 2020-10-13 4:32 a.m., Jehan-Guillaume de Rorthais wrote:
>>> On Mon, 12 Oct 2020 19:08:39 -0400
>>> Digimer <lists at alteeve.ca> wrote:
>>>  
>>>> Hi all,  
>>>
>>> Hi you,
>>>  
>>>>
>>>>  I noticed that there appear to be a global "maintenance mode"
>>>> attribute under cluster_property_set. This seems to be independent of
>>>> node maintenance mode. It seemed to not change even when using
>>>> 'pcs node maintenance --all'  
>>>
>>> You can set maintenance-mode using:
>>>
>>>  pcs property set maintenance-mode=true
>>>
>>> You can read about "maintenance-mode" cluster attribute and "maintenance"
>>> node attribute in chapters:
>>>
>>>  https://clusterlabs.org/pacemaker/doc/en-US/Pacemaker/2.0/html/Pacemaker_Explained/s-cluster-options.html 
>>>  https://clusterlabs.org/pacemaker/doc/en-US/Pacemaker/2.0/html/Pacemaker_Explained/_special_node_attributes.html
>>>
>>> I would bet the difference is that "maintenance-mode" applies to all nodes
>>> in one single action. Using 'pcs node maintenance --all', each pcsd daemon
>>> apply the local node maintenance independently. 
>>>
>>> With the later, I suppose you might have some lag between nodes to actually
>>> start the maintenance, depending on external factors. Moreover, you can
>>> start/exit the maintenance mode independently on each nodes.  
>>
>> Thanks for this.
>>
>> A question remains; Is it possible that:
>>
>> <nvpair id="cib-bootstrap-options-maintenance-mode"
>> name="maintenance-mode" value="false"/>
>>
>> Could be set, and a given node could be:
>>
>> <node id="1" uname="mk-a02n01">
>>  <instance_attributes id="nodes-1">
>>    <nvpair id="nodes-1-maintenance" name="maintenance" value="off"/>
>>  </instance_attributes>
>> </node>
>>
>> That is to say; If the cluster is set to maintenance mode, does that
>> mean I should consider all nodes to also be in maintenance mode,
>> regardless of what their individual maintenance mode might be set to?
> 
> I remember a similar discussion happening some months ago. I believe Ken
> answered your question there:
> 
>  https://lists.clusterlabs.org/pipermail/developers/2019-November/002242.html
> 
> The whole answer is informative, but the conclusion might answer your
> question:
> 
>  >> There is some room for coming up with better option naming and meaning. For
>  >> example maybe the cluster-wide "maintenance-mode" should be something
>  >> like "force-maintenance" to make clear it takes precedence over node and
>  >> resource maintenance. 
> 
> I understand here that "maintenance-mode" takes precedence over individual node
> maintenance mode.
> 
> Regards,

Very helpful, thank you kindly!

-- 
Digimer
Papers and Projects: https://alteeve.com/w/
"I am, somehow, less interested in the weight and convolutions of
Einstein’s brain than in the near certainty that people of equal talent
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