[ClusterLabs] Q: rulke-based operation pause/freeze?

[Ondrej]

On 3/5/20 9:24 PM, Ulrich Windl wrote:
> Hi!
> 
> I'm wondering whether it's possible to pause/freeze specific resource operations through rules.
> The idea is something like this: If your monitor operation needes (e.g.) some external NFS server, and thst NFS server is known to be down, it seems better to delay the monitor operation until NFS is up again, rather than forcing a monitor timeout that will most likely be followed by a stop operation that will also time out, eventually killing the node (which has no problem itself).
> 
> As I guess it's not possible right now, what would be needed to make this work?
> In case it's possible, how would an example scenario look like?
> 
> Regards,
> Ulrich
> 

Hi Ulrich,

For 'monitor' operation you can disable it with approach described here 
at 
https://clusterlabs.org/pacemaker/doc/en-US/Pacemaker/1.1/html/Pacemaker_Explained/_disabling_a_monitor_operation.html

 > "followed by a stop operation that will also time out, eventually 
killing the node (which has no problem itself)"
This sounds to me as the resource agent "feature" and I would expect 
that different resources agents would have different behavior when 
something is lost/not present.

To me the idea here looks like "maintenance period" for some resource.
Is your expectation that cluster would not for some time do anything 
with some resources?
(In such case I would consider 'is-managed'=false + disabling monitor)
https://clusterlabs.org/pacemaker/doc/en-US/Pacemaker/1.1/html/Pacemaker_Explained/s-resource-options.html#_resource_meta_attributes

To determine _when_ this state should be enabled and disabled would be a 
different story.

--
Ondrej Famera