If one wishes to test if a host has a particular IP address (such as a floating
virtual address) or has an interface on a particular network (such as a
secondary management network), the facts that provide this information are
difficult to use within Puppet.
This patch addresses these needs by implementing functions
‘has_ip_address(value)’ and ‘has_ip_network(value)’. These functions look
through all interfaces for ipaddress_<interface> and network_<interface>
(respectively) having the requested <value>.
These functions are implemented on top of a lower-level predicate
function, ‘has_interface_with(kind, value)’, which iterates through the
interfaces in the ‘interfaces’ fact and checks the facts <kind>_<interface>
looking for <value>.
Additionally, the existence of a particular named interface can be checked for
by calling with only a single argument: has_interface_with(interface).
A Boolean is returned in all cases.
