[Openstack-operators] [openstack-dev] Scheduler proposal

Maish Saidel-Keesing maishsk at maishsk.com
Thu Oct 8 07:14:55 UTC 2015

Forgive the top-post.

Cross-posting to openstack-operators for their feedback as well.

Ed the work seems very promising, and I am interested to see how this 

With my operator hat on I have one piece of feedback.

By adding in a new Database solution (Cassandra) we are now up to three 
different database solutions in use in OpenStack

MySQL (practically everything)
MongoDB (Ceilometer)

Not to mention two different message queues
Kafka (Monasca)
RabbitMQ (everything else)

Operational overhead has a cost - maintaining 3 different database 
tools, backing them up, providing HA, etc. has operational cost.

This is not to say that this cannot be overseen, but it should be taken 
into consideration.

And *if* they can be consolidated into an agreed solution across the 
whole of OpenStack - that would be highly beneficial (IMHO).

Best Regards,
Maish Saidel-Keesing

On 10/08/15 03:24, Ed Leafe wrote:
> 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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