Two Node RHEL7 Cluster Without Quorumd

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux 7
  • High Availability

Issue

  • How can a two node RHEL7 cluster remain quorate after the loss of one node?

  • Since Pacemaker does not support qdisk we are looking for a way to keep a two node RHEL7 cluster quorate after the loss of one node.

Resolution

Qdisk has been discontinued for RHEL7 and pacemaker. However, there is a way to create a two node cluster which will remain quorate even after the failure of one of the nodes.

When creating a two node cluster with RHEL7's pacemaker the parameter 'two_node' is automatically set for corosync.

The following outputs are from a cluster created with the pcs command without the 'two_node' option being specifically mentioned:


# corosync-quorumtool -s

Quorum information
------------------
Date:             Wed Oct 29 12:04:11 2014
Quorum provider:  corosync_votequorum
Nodes:            2
Node ID:          1
Ring ID:          20
Quorate:          Yes

Votequorum information
----------------------
Expected votes:   2
Highest expected: 2
Total votes:      2
Quorum:           1                                <----
Flags:            2Node Quorate WaitForAll         <----

The 'two_node' parameter sets the quorum to '1' and allows one node to remain quorate and continue cluster operations after the second one is fenced.

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