A network failure of a host occurred in a VMware vSphere Foundation (VVF) vSphere cluster.

In this scenario, anetwork failureoccurred on a host, and VMs on that host didnot restart on other hosts, even thoughHA and DRS were enabled.

This indicates thatvSphere HA detected an isolation event(the host lost network connectivity) but tookno action, because theHost Isolation Response was disabled.

Normally, with Host Isolation Response set to "Power Off and Restart VMs," HA restarts affected VMs on surviving hosts.

Since powering off a host manually triggers a restart correctly, the failure here was specific toisolation behavior.

Other options:

B. Affinity rule "should run on"→ Would still allow HA restart elsewhere if isolation occurred.

C. DRS not enabled→ DRS only balances load; HA is responsible for restarts.

D. HA not enabled→ Contradicts the scenario (HA was enabled).