As already mentioned, the quorum provider in the CentOS 7 cluster stack is Corosync version 2. Therefore, the cluster quorum configuration is provided in the corosync.conf configuration file. With the previous Corosync version (version 1), the quorum capabilities were provided by CMAN; with Corosync version 2 included in the CentOS 7 cluster stack, the quorum capabilities are provided by Corosync itself, specifically by the votequorum process.

If you are configuring a two-node cluster on the CentOS 7 cluster stack, you should enable the two_node cluster option by adding the following parameter to the corosync.conf Quorum section:

two_node: 1

By enabling the two_node cluster option, the quorum is artificially set to 1, which means that the cluster will be quorate and continue to operate even in the event of a failure of one cluster node. Note that enabling the two_node cluster option automatically enables an additional wait_for_all option, which is explained...