[ClusterLabs] SAPHanaController & SAPHanaTopology question

[Reid Wahl]

Hi, Strahil.

Based on the constraints documented in the article you're following (RH KB
solution 5423971), I think I see what's happening.

The SAPHanaTopology resource requires the appropriate nfs-active attribute
in order to run. That means that if the nfs-active attribute is set to
false, the SAPHanaTopology resource must stop.

However, there's no rule saying SAPHanaTopology must finish stopping before
the nfs-active attribute resource stops. In fact, it's quite the opposite:
the SAPHanaTopology resource stops only after the nfs-active resource stops.

At the same time, the NFS resources are allowed to stop after the
nfs-active attribute resource has stopped. So the NFS resources are
stopping while the SAPHana* resources are likely still active.

Try something like this:
    # pcs constraint order hana_nfs1_active-clone then
SAPHanaTopology_<SID>_<instance_num>-clone kind=Optional
    # pcs constraint order hana_nfs2_active-clone then
SAPHanaTopology_<SID>_<instance_num>-clone kind=Optional

This says "if both hana_nfs1_active and SAPHanaTopology are scheduled to
start, then make hana_nfs1_active start first. If both are scheduled to
stop, then make SAPHanaTopology stop first."

"kind=Optional" means there's no order dependency unless both resources are
already going to be scheduled for the action. I'm using kind=Optional here
even though kind=Mandatory (the default) would make sense, because IIRC
there were some unexpected interactions with ordering constraints for
clones, where events on one node had unwanted effects on other nodes.

I'm not able to test right now since setting up an environment for this
even with dummy resources is non-trivial -- but you're welcome to try this
both with and without kind=Optional if you'd like.

Please let us know how this goes.

On Fri, Apr 2, 2021 at 2:20 AM Strahil Nikolov <hunter86_bg at yahoo.com>
wrote:

> Hello All,
>
> I am testing the newly built HANA (Scale-out) cluster and it seems that:
> Neither SAPHanaController, nor SAPHanaTopology are stopping the HANA when
> I put the nodes (same DC = same HANA) in standby. This of course leads to a
> situation where the NFS cannot be umounted and despite the stop timeout  -
> leads to fencing(on-fail=fence).
>
> I thought that the Controller resource agent is stopping the HANA and the
> slave role should not be 'stopped' before that .
>
> Maybe my expectations are wrong ?
>
> Best Regards,
> Strahil Nikolov
>
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-- 
Regards,

Reid Wahl, RHCA
Senior Software Maintenance Engineer, Red Hat
CEE - Platform Support Delivery - ClusterHA
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