Storage based heartbeat for HA
This additional measure is needed for forcing behavior on network partitions. Consul based concensus will correctly mark the host separated by partition. However, in this situation, the VMs and other services run fine on the host. We can
1. Either do nothing, the workloads keep running with network partition
2. Take evacuation action. In this case the domains should be destroyed on source and some indication given to the destination to proceed with evacuate. We also need to ensure that all hosts in the partition are correctly marked as 'down' before evacuation.