[Openstack] Keystone and Horizon questions

Clint Byrum clint at fewbar.com
Sun Aug 24 06:10:09 UTC 2014

Excerpts from Marcus White's message of 2014-08-23 21:17:24 -0700:
> Thank you Clint, had some follow up questions inline:)
> On Sun, Aug 24, 2014 at 12:12 AM, Clint Byrum <clint at fewbar.com> wrote:
> > Excerpts from Marcus White's message of 2014-08-23 09:55:24 -0700:
> >> Hello,
> >> I had some keystone and Horizon questions, would apprecite it if
> >> anyone can help:-)
> >>
> >> a. Does Keystone run as a service scaled across multiple nodes? Since
> >> it would need access to shared data, I dont understand how it scales.
> >>
> >
> > It stores data in various backends. The default is SQL, and many use
> > LDAP to link with existing ID stores.
> >
> > It runs as a REST API in front of those data backends, and scales out
> > quite nicely like any other web application.
> For SQL, if SQL runs on Keystone with every node, how is the data on
> all nodes synchronized? Does the SQL server run externally as a
> service? I read somewhere that SQL runs with keystone hence the
> qstion.

You read something false. The reality is it uses "sqlalchemy", so people
use MySQL, DB2, and Postgres, to name a few I've seen bug reports for.

Many organizations using MySQL/MariaDB with OpenStack use Galera
synchronous replication to allow HA and read scaling (writes are sent
to all nodes).

> >
> >> b. If it does not run on multiple nodes as a service, how can it
> >> handle a large number of concurrent requests?
> >>
> >> c. Is it expected to be a service that is exposed to the clients on a
> >> public cloud? Does Rackspace today do it or any other public cloud?
> >>
> >
> > Yes it is expected to be exposed. Users authenticate to keystone and are
> > given a token which can be used to grant access to the other OpenStack
> > services.
> >
> >> Some horizon questions also
> >>
> >> a. Does Horizon allow customization for specific services? Is there
> >> any way to add value on top of it for my own Nova or Swift or Cinder
> >> view, can I do that or is it whatever is done by the community the
> >> only thing available?
> >>
> >
> > It's open source. Go wild. ;) I believe there are hooks for
> > skins/themes, and one can add plugins for other functionality.
> Can I change the full view of how the Nova part or Cinder part of
> Swift part looks completely and even present a different set of data?

I Really don't know. We've reached the end of my knowledge of Horizon.

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