'Picks a host that is up at random.'

def _schedule(self, context, topic, spec_obj):

    elevated = context.elevated()
    hosts = self.hosts_up(elevated, topic)
    if (not hosts):
        msg = _('Is    the    appropriate    service    running?')
        raise exception.NoValidHost(reason=msg)
    hosts = self._filter_hosts(hosts, spec_obj)
    if (not hosts):
        msg = _('Could    not    find    another    compute')
        raise exception.NoValidHost(reason=msg)
    return random.choice(hosts)
