Create a db2cm maintenance mode for HADR + Pacemaker

Db2 v12.1.x
HADR + Pacemaker
Linux

Problem:

Db2 PureScale has an easy way to put a host from the cluster in maintenance mode that is:

db2cm -enter -maintenance

Db2 HADR + Pacemaker has the :

db2cm -DISABLE -instance <instance_name> -host <hostname>

But that command is very limited.

There is a Pacemaker command (bundle from Db2) that is:

v11.5:

pcs node standby <host>

v12.1:

crm_standby -v ON/OFF -N <host>

Those Pacemaker commands are much more completed then db2cm -disable, for maintenance scenarios.

Customer usually needs to do maintenance on Standby hosts (when need to do a maintenance in the primary, they first run a takeover and do the maintenance in the New Standby).

Having only one easy command to put the host in maintenance mode is much more safety once it avoids errors due to manual commands.

I made comparison table sheet show the difference between those methods. (There is an Excel sheet attached with better view)
 

Test on v12.1.4.0

=========================================================================================
If run for the STANDBY host
=========================================================================================

Action                                                           db2cm-DISABLE   crm_standby -v ON
-----------------------------------------------------------------------------------------
Disables the Pacemaker only in the specified host                     TRUE             TRUE
Automatically brings the Standby VIP offline                          FALSE            TRUE
Automatically stops Db2 instance                                      FALSE            TRUE

=========================================================================================
If run for the PRIMARY host
=========================================================================================

Action                                                           db2cm-DISABLE   crm_standby -v ON
-----------------------------------------------------------------------------------------
Disables the Pacemaker only in the specified host                     TRUE             TRUE
Automatically runs a takeover                                                             FALSE            TRUE
Automatically brings the Primary VIP offline in old Primary           FALSE            TRUE
Automatically starts the Primary VIP in the new Primary               FALSE            TRUE
Automatically stops the Db2 instance in the old Primary               FALSE            TRUE

=========================================================================================
If run for the OLD PRIMARY host
=========================================================================================

Action                                                           db2cm-ENABLE    crm_standby -v OFF
-----------------------------------------------------------------------------------------
Enables the Pacemaker only in the specified host                      TRUE             TRUE
Automatically brings the Standby VIP online in old Primary            FALSE            TRUE
Automatically starts the Db2 instance in the old Primary              FALSE            TRUE

=========================================================================================
NOTE
=========================================================================================

Behavior is the same on Db2 v11.5.9.0, but using:

   pcs node standby <host>

instead of:

   crm_standby

**************

Thanks
Felipe

.