3-node-cluster

I 've a 3-node cluster, A-B-C

1) set iptables on A to block B

2) set iptables on B to block A


In fact, it will occurs as following:
On node C:
Mar 16 10:59:57 bliu-sle12sp1-node3 corosync[5952]:   [TOTEM ] A new membership (10.67.162.84:28) was formed. Members left: 172204627
Mar 16 10:59:57 bliu-sle12sp1-node3 corosync[5952]:   [TOTEM ] Failed to receive the leave message. failed: 172204627
Mar 16 10:59:57 bliu-sle12sp1-node3 corosync[5952]:   [QUORUM] Members[2]: 172204628 172204629
Mar 16 10:59:57 bliu-sle12sp1-node3 corosync[5952]:   [MAIN  ] Completed service synchronization, ready to provide service.

On node B:
Mar 16 11:00:03 bliu-sle12sp1-node1 corosync[5964]:   [TOTEM ] A new membership (10.67.162.83:28) was formed. Members left: 172204628 172204629
Mar 16 11:00:03 bliu-sle12sp1-node1 corosync[5964]:   [TOTEM ] Failed to receive the leave message. failed: 172204628 172204629
Mar 16 11:00:03 bliu-sle12sp1-node1 corosync[5964]:   [QUORUM] This node is within the non-primary component and will NOT provide any services.

On node A:
Mar 16 10:59:50 bliu-sle12sp1-node2 corosync[5965]:   [TOTEM ] A processor failed, forming new configuration.
Mar 16 10:59:56 bliu-sle12sp1-node2 corosync[5965]:   [TOTEM ] A new membership (10.67.162.84:28) was formed. Members left: 172204627
Mar 16 10:59:56 bliu-sle12sp1-node2 corosync[5965]:   [TOTEM ] Failed to receive the leave message. failed: 172204627
Mar 16 10:59:56 bliu-sle12sp1-node2 corosync[5965]:   [QUORUM] Members[2]: 172204628 172204629
Mar 16 10:59:56 bliu-sle12sp1-node2 corosync[5965]:   [MAIN  ] Completed service synchronization, ready to provide service.


the cluster split into two components in fact, one with quorum, the other without quorum

so far everything is expected. I 've two questions about this condition:

1) is there race between A and B to get the vote from C, which means it is random that A or B get consensus with C? but I repeated several times, it seems that A always

got consensus with C. Maybe it is just an accidental condition.

2) is there mechanism for this condition to decide A or B always got consensus with C? except the qdevice solution:)