[Openstack-operators] memcached redundancy

Juan José Pavlik Salles jjpavlik at gmail.com
Thu Aug 14 19:22:37 UTC 2014

It might not be the best idea ever, but it worked for me. There's a
memcached patch called repcached that allows you to have 2 memcached
servers sincronized (as far as I now, it just works for 2 servers) with
each other, this way you get HA and LB. The patch source is
here you've got a little example
on Ubuntu 12.04 (sorry about the spanish link, but the steps are pretty
straight forward).

2014-08-14 16:05 GMT-03:00 Daneyon Hansen (danehans) <danehans at cisco.com>:

>  It has been a while, but I believe I load-balanced memcached using
> HAProxy (using sticky sessions) and observed no issues with fail-over.
>  Regards,
> Daneyon Hansen
> Software Engineer
> Email: danehans at cisco.com
> Phone: 303-718-0400
> http://about.me/daneyon_hansen
>   From: Joe Topjian <joe at topjian.net>
> Date: Thursday, August 14, 2014 10:09 AM
> To: "openstack-operators at lists.openstack.org" <
> openstack-operators at lists.openstack.org>
> Subject: [Openstack-operators] memcached redundancy
>   Hello,
>  I have an OpenStack cloud with two HA cloud controllers. Each controller
> runs the standard controller components: glance, keystone, nova minus
> compute and network, cinder, horizon, mysql, rabbitmq, and memcached.
>  Everything except memcached is accessed through haproxy and everything
> is working great (well, rabbit can be finicky ... I might post about that
> if it continues).
>  The problem I currently have is how to effectively work with memcached
> in this environment. Since all components are load balanced, they need
> access to the same memcached servers. That's solved by the ability to
> specify multiple memcached servers in the various openstack config files.
>  But if I take a server down for maintenance, I notice a 2-3 second delay
> in all requests. I've confirmed it's memcached by editing the list of
> memcached servers in the config files and the delay goes away.
>  I'm wondering how people deploy memcached in environments like this? Are
> you using some type of memcached replication between servers? Or if a
> memcached server goes offline are you reconfiguring OpenStack to remove the
> offline memcached server?
>  Thanks,
> Joe
> _______________________________________________
> OpenStack-operators mailing list
> OpenStack-operators at lists.openstack.org
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Pavlik Salles Juan José
Blog - http://viviendolared.blogspot.com
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