Clustering ESXi hosts for high availability

VMware vSphere HA (high availability) is a functionality that is used to configure a cluster of ESXi hosts to respond to an unplanned downtime event and ensure the availability of the virtual machines that were running on them, with very minimal downtime possible. Although that was a very simple definition, there is more to what vSphere HA can do in terms of providing high availability to the virtual machines running on the HA protected hosts. It can monitor the guest operating systems and the applications running inside of a virtual machine and then decide to restart the affected virtual machine in an effort to reduce the downtime of a service due to an affected guest operating system hosting the service, or a nonresponsive application corresponding to the service. Starting with vSphere 6.0, it can also detect APD and PDL events and choose to reset the virtual machines if necessary. However, it is important to understand that even though HA is...