The Alias module provides the means to define an alternate network address
   which is shared by multiple nodes in the same VMScluster. This makes it
   possible to treat a VMScluster, or several nodes within a VMScluster, as
   though it were a single node in the network.

   The alias entity is the top-level entity in the hierarchy belonging to the
   Alias module. The entity is the root from which alias port subentities may
   be defined.