Checar o status do cluster:

# crm_mon -1
# pcs status

Checar o status dos recursos:

# crm resource status

Checando as configurações válidas:

# crm_verify -L -V

Editar as configurações:

# crm configure edit

Depois de salvar as alterações através do editor de texto preferido, saia e execute:

# cibadmin --replace

Testando o Failover

No nó primário SRVP1 execute os comandos abaixo:

# crm node standby

Durante o processo você pode acompanhar usando o:

# tail -f /var/log/messages

Depois:

# pcs status
pcs status
Cluster name: zcsCluster
Last updated: Wed Nov 4 16:29:14 2015
Last change: Wed Nov 4 16:29:11 2015
Stack: cman
Current DC: srvp1.linuxajuda.org - partition with quorum
Version: 1.1.11-97629de
2 Nodes configured
5 Resources configured

Node srvp1.linuxajuda.org: standby
Online: [ srvp2.linuxajuda.org ]

Full list of resources:

VIP1   (ocf::heartbeat:IPaddr2):       Started srvp1.linuxajuda.org
Master/Slave Set: drbd_ms [drbd]
     Masters: [ srvp1.linuxajuda.org ]
     Slaves: [ srvp2.linuxajuda.org ]
Resource Group: zcsgroup
     zcs_fs     (ocf::heartbeat:Filesystem):    Started srvp1.linuxajuda.org
zcs_service    (ocf::btactic:zimbra):  Started srvp1.linuxajuda.org

Depois de alguns minutos rode novamente o comando:

# pcs status
pcs status
Cluster name: zcsCluster
Last updated: Wed Nov 4 16:31:52 2015
Last change: Wed Nov 4 16:28:35 2015
Stack: cman
Current DC: srvp1.linuxajuda.org - partition with quorum
Version: 1.1.11-97629de
2 Nodes configured
5 Resources configured

Node srvp1.linuxajuda.org: standby
Online: [ srvp2.linuxajuda.org ]
Full list of resources:

VIP1   (ocf::heartbeat:IPaddr2):       Started srvp2.linuxajuda.org
Master/Slave Set: drbd_ms [drbd]
     Masters: [ srvp2.linuxajuda.org ]
     Stopped: [ srvp1.linuxajuda.org ]
Resource Group: zcsgroup
     zcs_fs     (ocf::heartbeat:Filesystem):    Started srvp2.linuxajuda.org
zcs_service    (ocf::btactic:zimbra):  Started srvp2.linuxajuda.org

Para voltar o nó primário digite:

# crm node online

Depois de alguns minutos:

# cat /proc/drbd
version: 8.4.6 (api:1/proto:86-101)
GIT-hash: 833d830e0152d1e457fa7856e71e11248ccf3f70 build by phil@Build64R6, 2015-04-09 14:35:00
0: cs:StandAlone ro:Primary/Unknown ds:UpToDate/DUnknown r-----ns:0 nr:0 dw:24196 dr:448905 al:32 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:21032

Remonte o cluster.

No nó secundário:

# drbdadm secondary all
# drbdadm disconnect all
# drbdadm -- --discard-my-data connect all

No nó primário:

# drbdadm primary all
# drbdadm disconnect all
# drbdadm connect all

# cat /proc/drbd
version: 8.4.6 (api:1/proto:86-101)
GIT-hash: 833d830e0152d1e457fa7856e71e11248ccf3f70 build by phil@Build64R6, 2015-04-09 14:35:00
0: cs:SyncSource ro:Primary/Secondary ds:UpToDate/Inconsistent C r-----
    ns:21884 nr:0 dw:28368 dr:470813 al:33 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:2908
        [===================>] sync'ed:100.0% (2908/24776)K
        finish: 0:00:00 speed: 21,868 (21,868) K/sec

Pronto, seu cluster de alta disponibilidade estará funcionando.