Open Stack

> As providing OpenStack community with understandable recommendations
> and instructions on performant OpenStack cloud deployments is part
> of Performance Team mission, I'm kindly asking you to share your
> experience on safe cloud deployment ratio between various types of
> nodes you're having right now and the possible issues you observed
> (as an example: discussed GoDaddy's cloud is having 3 conductor boxes
> vs 250 computes in the cell, and there was an opinion that it's
> simply not enough and that's it).

That was my opinion, and it was based on an apparently incorrect
assumption that they had a lot of things coming and going on their
cloud. I think they've demonstrated at this point that (other issues
aside) three is enough for them, given their environment, workload, and
configuration.

The problem with coming up with any sort of metric that will apply to
everyone is that it's highly variable. If you have 250 compute nodes and
never create or destroy any instances, you'll be able to get away with
*many* fewer conductors than if you have a very active cloud. Similarly,
during a live upgrade (or following any upgrade where we do some online
migration of data), your conductor load will be higher than normal. Of
course, 4-core and 96-core conductor nodes aren't equal either.

So, by all means, we should gather information on what people are doing
successfully, but keep in mind that it depends *a lot* on what sort of
workloads the cloud is supporting.

--Dan