'Confirms a Nova hypervisor node exists in the Ironic inventory.
:param nodename: The UUID of the node.
:returns: True if the node exists, False if not.'

def node_is_available(self, nodename):

    if (not self.node_cache):
        self._refresh_cache()
    if (nodename in self.node_cache):
        return True
    try:
        self._get_node(nodename)
        return True
    except ironic.exc.NotFound:
        return False
