openstack/oslo.messaging
Code Issues Proposed changes

rabbit: shuffle hosts before building kombu URL

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This restores behavior as it was back in the Juno cycle.  This was
changed in a refactor during the Kilo cycle (973301aa) when the kombu
failover_strategy was set to shuffle.  But the failover_strategy only
affects failovers; it does not influence which host receives the
initial connection.

Thus, if multiple hosts are given, the first host will receive all of
the initial connections.  By shuffling the hosts before building the
URL given to kombu, rudimentary load balancing is achieved and
connections are more evenly spread across broker nodes.

Change-Id: Ieecaf5f286f49302db29df9854359ef5d36b7a89
This commit is contained in:
John Eckersberg 2015-10-02 13:47:21 -04:00
parent 3a5db723aa
commit f2beb5eaf1
1 changed files with 3 additions and 0 deletions
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3
oslo_messaging/_drivers/impl_rabbit.py
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@ -16,6 +16,7 @@ import collections
import contextlib
import functools
import os
import random
import socket
import ssl
import threading
@ -406,6 +407,7 @@ class Connection(object):
LOG.warn(_LW('Selecting the kombu transport through the '
'transport url (%s) is a experimental feature '
'and this is not yet supported.') % url.transport)
random.shuffle(url.hosts)
for host in url.hosts:
transport = url.transport.replace('kombu+', '')
transport = transport.replace('rabbit', 'amqp')
@ -423,6 +425,7 @@ class Connection(object):
transport = url.transport.replace('kombu+', '')
self._url = "%s://%s" % (transport, virtual_host)
else:
random.shuffle(self.rabbit_hosts)
for adr in self.rabbit_hosts:
hostname, port = netutils.parse_host_port(
adr, default_port=self.rabbit_port)