def get_availability_zone_hosts(nova, zone_name='nova'):
    """
    Returns the names of all nova active compute servers
    :param nova: the Nova client
    :param zone_name: the Nova client
    :return: a list of compute server names
    """
    out = list()
    zones = nova.availability_zones.list()
    for zone in zones:
        if zone.zoneName == zone_name and zone.hosts:
            for key, host in zone.hosts.items():
                if host['nova-compute']['available']:
                    out.append(zone.zoneName + ':' + key)
    return out
