In some case, force reboot or shutdown operation hang, and cannot to perform, this is steps to clear the pending process and re-run it-
1. “xe vm-list” to get the uuid of the VM that is hung
2. “list_domains” to list the domain uuid’s so you can determine the domain # of the VM above by matching the uuids from this output with the uuid for your VM from the previous command.
3. “/opt/xensource/debug/destroy_domain -domid XX” where XX is the domain number from the previous command
4. “xe vm-reboot uuid=XXXX –force” where XXXX is the uuid from the first vm-list command for your VM. (name-label may work but didn’t work this time for me so I used the uuid)