'Forces the master to sync with the other data servers.'

def _Sync(self):

    pool = None
    try:
        pool = urllib3.connectionpool.HTTPConnectionPool(self.addr, port=self.port)
        body = ''
        headers = {'Content-Length': len(body)}
        res = pool.urlopen('POST', '/servers/sync-all', headers=headers, body=body)
        if (res.status == constants.RESPONSE_INCOMPLETE_SYNC):
            print 'Master    has    tried    to    contact    all    the    data    servers,    but    failed.'
            return False
        if (res.status == constants.RESPONSE_DATA_SERVERS_UNREACHABLE):
            print 'Master    server    says    that    some    data    servers    are    not    running.'
            print 'Giving    up...'
            return False
        if (res.status != constants.RESPONSE_OK):
            print 'Unable    to    sync    servers.'
            return False
    except urllib3.exceptions.MaxRetryError:
        print 'Unable    to    contact    master...'
        return False
    print 'Sync    done.'
    self.mapping = rdf_data_server.DataServerMapping.FromSerializedString(res.data)
    return True
