[ClusterLabs] DRBD on asymmetric-cluster

[Jason Voorhees]

Hello guys:

I've been recently reading "Pacemaker - Clusters from scratch" and
working on a CentOS 7 system with pacemaker 1.1.13, corosync-2.3.4 and
drbd84-utils-8.9.5.

The PDF instructs how to create a DRBD resource that seems to be
automatically started due to a symmetric-cluster setup.

However I want to setup an asymmetric-cluster/opt-in
(symmetric-cluster=false) but I don't know how to configure a
constraint to prefer node1 over node2 to start my DRBD resource as
Master (Primary).

So far this are my resources and constraints:

[root at nodo1 ~]# pcs resource
 IPService      (ocf::heartbeat:IPaddr2):       Started nodo1
 Web    (systemd:httpd):        Started nodo1
 Master/Slave Set: clusterdataClone [clusterdata]
     Stopped: [ nodo1 nodo2 ]

[root at nodo1 ~]# pcs constraint
Location Constraints:
  Resource: IPService
    Enabled on: nodo2 (score:50)
    Enabled on: nodo1 (score:100)
  Resource: Web
    Enabled on: nodo2 (score:50)
    Enabled on: nodo1 (score:100)
Ordering Constraints:
  start IPService then start Web (kind:Mandatory)
Colocation Constraints:
  Web with IPService (score:INFINITY)

My current DRBD status:

[root at nodo1 ~]# drbdadm role clusterdb
0: Failure: (127) Device minor not allocated
additional info from kernel:
unknown minor
Command 'drbdsetup-84 role 0' terminated with exit code 10


[root at nodo2 ~]# drbdadm role clusterdb
0: Failure: (127) Device minor not allocated
additional info from kernel:
unknown minor
Command 'drbdsetup-84 role 0' terminated with exit code 10


I know that it's possible to configure my cluster as asymmetric and
use constraints to avoid a resource running (or becoming master) on
certain nodes, but this time I would like to learn how to do it with
an opt-in scenario.

Thanks in advance for your help.

P.D. nodo1 & nodo2 are spanish names for node1 and node2