[ClusterLabs] constraining multiple cloned resources to the same node

[john tillman]

Hello,

I'm trying to guarantee that all my cloned drbd resources start on the
same node and I can't figure out the syntax of the constraint to do it.

I could nominate one of the drbd resources as a "leader" and have all the
others follow it.  But then if something happens to that leader the others
are without constraint.

I tried adding them to a group but got a syntax error from pcs saying that
I wasn't allowed to add cloned resources to a group.

If anyone is interested, it started from this example:
https://edmondcck.medium.com/setup-a-highly-available-nfs-cluster-with-disk-encryption-using-luks-drbd-corosync-and-pacemaker-a96a5bdffcf8
There's a DRBD partition that gets mounted onto a local directory.  The
local directory is then mounted onto an exported directory (mount --bind).
 Then the nfs service (samba too) get started and finally the VIP.

Please note that while I have 3 DRBD resources currently, that number may
increase after the initial configuration is performed.

I would just like to know a mechanism to make sure all the DRBD resources
are colocated.  Any suggestions welcome.

[root at nas00 ansible]# pcs resource
  * Clone Set: drbdShare-clone [drbdShare] (promotable):
    * Masters: [ nas00 ]
    * Slaves: [ nas01 ]
  * Clone Set: drbdShareRead-clone [drbdShareRead] (promotable):
    * Masters: [ nas00 ]
    * Slaves: [ nas01 ]
  * Clone Set: drbdShareWrite-clone [drbdShareWrite] (promotable):
    * Masters: [ nas00 ]
    * Slaves: [ nas01 ]
  * localShare    (ocf::heartbeat:Filesystem):     Started nas00
  * localShareRead    (ocf::heartbeat:Filesystem):     Started nas00
  * localShareWrite   (ocf::heartbeat:Filesystem):     Started nas00
  * nfsShare      (ocf::heartbeat:Filesystem):     Started nas00
  * nfsShareRead      (ocf::heartbeat:Filesystem):     Started nas00
  * nfsShareWrite     (ocf::heartbeat:Filesystem):     Started nas00
  * nfsService  (systemd:nfs-server):    Started nas00
  * smbService  (systemd:smb):   Started nas00
  * vipN      (ocf::heartbeat:IPaddr2):        Started nas00

[root at nas00 ansible]# pcs constraint show --all
Location Constraints:
Ordering Constraints:
  promote drbdShare-clone then start localShare (kind:Mandatory)
  promote drbdShareRead-clone then start localShareRead (kind:Mandatory)
  promote drbdShareWrite-clone then start localShareWrite (kind:Mandatory)
  start localShare then start nfsShare (kind:Mandatory)
  start localShareRead then start nfsShareRead (kind:Mandatory)
  start localShareWrite then start nfsShareWrite (kind:Mandatory)
  start nfsShare then start nfsService (kind:Mandatory)
  start nfsShareRead then start nfsService (kind:Mandatory)
  start nfsShareWrite then start nfsService (kind:Mandatory)
  start nfsService then start smbService (kind:Mandatory)
  start nfsService then start vipN (kind:Mandatory)
Colocation Constraints:
  localShare with drbdShare-clone (score:INFINITY) (with-rsc-role:Master)
  localShareRead with drbdShareRead-clone (score:INFINITY)
(with-rsc-role:Master)
  localShareWrite with drbdShareWrite-clone (score:INFINITY)
(with-rsc-role:Master)
  nfsShare with localShare (score:INFINITY)
  nfsShareRead with localShareRead (score:INFINITY)
  nfsShareWrite with localShareWrite (score:INFINITY)
  nfsService with nfsShare (score:INFINITY)
  nfsService with nfsShareRead (score:INFINITY)
  nfsService with nfsShareWrite (score:INFINITY)
  smbService with nfsShare (score:INFINITY)
  smbService with nfsShareRead (score:INFINITY)
  smbService with nfsShareWrite (score:INFINITY)
  vipN with nfsService (score:INFINITY)
Ticket Constraints:

Thank you for your time and attention.

-John