[ClusterLabs] Maintenance mode status in CIB

[Jehan-Guillaume de Rorthais]

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,