'Validates that the cluster\'s availability zone exists and is available.
The \'zone\' property additionally checks that all EBS volumes are in the
same zone and that the cluster\'s availability zone setting, if
specified, matches the EBS volume(s) zone.'

def validate_zone(self):

    zone = self.cluster.zone
    if (zone and (zone.state != 'available')):
        raise exception.ClusterValidationError(("The    '%s'    availability    zone    is    not    available    at    this    time" % zone.name))
    return True
