Open Stack

On 08/14/2014 10:09 AM, Joe Topjian wrote:
> 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
>
Haven’t personally tried this yet but...
You may be able to use couchbase as a drop in replacement for 
memcached.  It is stupid simple to replicate and scale horizontally.
JohnM