[openstack-dev] Scheduler proposal

Fox, Kevin M Kevin.Fox at pnnl.gov
Thu Oct 8 00:37:54 UTC 2015

I think if you went ahead and did the experiment, and had good results from it, the discussion would start to progress whether or not folks were fond of Cassandra or <insert random other db thingy here>...

From: Ed Leafe [ed at leafe.com]
Sent: Wednesday, October 07, 2015 5:24 PM
To: OpenStack Development Mailing List (not for usage questions)
Subject: Re: [openstack-dev] Scheduler proposal

On Oct 7, 2015, at 2:28 PM, Zane Bitter <zbitter at redhat.com> wrote:

> It seems to me (disclaimer: not a Nova dev) that which database to use is completely irrelevant to your proposal,

Well, not entirely. The difference is that what Cassandra offers that separates it from other DBs is exactly the feature that we need. The solution to the scheduler isn't to simply "use a database".

> which is really about moving the scheduling from a distributed collection of Python processes with ad-hoc (or sometimes completely missing) synchronisation into the database to take advantage of its well-defined semantics. But you've framed it in such a way as to guarantee that this never gets discussed, because everyone will be too busy arguing about whether or not Cassandra is better than Galera.

Understood - all one has to do is review the original thread from back in July to see this happening. But the reason that I framed it then as an experiment in which we would come up with measures of success we could all agree on up-front was so that if someone else thought that Product Foo would be even better, we could set up a similar test bed and try it out. IOW, instead of bikeshedding, if you want a different color, you build another shed and we can all have a look.

-- Ed Leafe

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