'Tell servers to copy files to the corresponding servers.'

def CopyRebalanceFiles(self):

    body = self.rebalance.SerializeToString()
    size = len(body)
    headers = {'Content-Length': size}
    for pool in self.rebalance_pool:
        try:
            res = pool.urlopen('POST', '/rebalance/copy', headers=headers, body=body)
            if (res.status != constants.RESPONSE_OK):
                self.CancelRebalancing()
                return False
        except urllib3.exceptions.MaxRetryError:
            self.CancelRebalancing()
            return False
    return True
