How is the primary host determined in a vSphere HA cluster?

In a vSphere High Availability (HA) cluster, the primary host is determined through an election process that takes into account datastore accessibility. When the HA cluster is established, the hosts communicate with each other to assess which has access to the shared storage and can provide the necessary resources to the virtual machines. This process is essential for ensuring that the cluster can effectively manage failovers and maintain uptime for the virtual machines.

During the election, each host evaluates its own state and the state of other hosts, including their ability to access critical resources like datastores and network connections. The host that is eligible and has the most accessible datastores typically becomes the primary host to manage the cluster’s operations, including monitoring the other hosts and handling failover procedures. This method ensures that the primary host is chosen based on objective criteria linked to resource availability, rather than an arbitrary method or manual decision-making.