+.. _fencing:
+
+Fencing
+^^^^^^^
+Recovery actions, e.g. safe VM evacuation, have to be preceded by fencing the
+failed host. Fencing hereby means to isolate or shut down a faulty resource.
+Without fencing -- when the perceived disconnection is due to some transient
+or partial failure -- the evacuation might lead into two identical instances
+running together and having a dangerous conflict.
+
+There is a cross-project effort in OpenStack ongoing to implement fencing. A
+general description of fencing in OpenStack is available here:
+https://wiki.openstack.org/wiki/Fencing_Instances_of_an_Unreachable_Host .
+