[ClusterLabs] Maintenance mode status in CIB

[Digimer]

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
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