An administrator logs into the vSphere client to check the health of a cluster. An alert appears on the cluster stating, "vSphere HA host status". The administrator toggles vSphere HA off and on and the following error appears on the host "A general system error occurred: Failed to start fdm service on host". What is the cause of this issue?
Yeah, that "failed to start fdm service" points right at A. If the service was just missing (like B), you'd usually get a different error about not finding the VIB. Seen similar messages in practice labs. Pretty confident it's A but open if someone found otherwise.
Seen this edge case before, and if the vmware-fdm service is just disabled (not missing), you'll get exactly that "failed to start fdm service" error. If the VIB was missing, you'd usually see a different message. Pretty sure it's A in this wording-let me know if you disagree.
I really think it's A here. When the fdm service is just disabled, you'll hit the "failed to start fdm" error as described-if the VIB was missing like in B, you'd get an install or package missing message instead. I've seen similar questions trip people up by making B sound tempting. Pretty sure about A, but let me know if there's a VMware version that behaves differently.