When priority settings are equal and the members participating in a cluster are initialized at the same time， the primary role for redundancy group 0 is assigned to node 0.
The preempt option determines the primary and secondary roles for redundancy group 0 during a failure and recovery scenario.
Redundancy group 0 manages the control plane failover between the nodes of a cluster.
The primary role can be shared for redundancy group 0 when the active-active option is enabled