From my understanding I have interpreted as below, is this correct?
Vmware Cluster(HA) - If we have cluster configured and if one of the ESX hosts failed, all the VMs which are running here will move over to another ESX host in the cluster farm without any downtime or reboot.
Vmware Vmotion: Vmotion uses to move VMs between the datacenter without down time
Vmware DRS: If we have enabled DRS, when usage is high on memory or cpu, it will move over to another ESX host in farm.
If'm wrong please correct me.