[Openstack] Keystone and Horizon questions

Lyle, David david.lyle at hp.com
Mon Aug 25 15:55:53 UTC 2014

On 8/24/14, 12:10 AM, "Clint Byrum" <clint at fewbar.com> wrote:

>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
>> > 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?

Horizon is designed to be extended and adapted. All that you have asked is
certainly possible without too much work other than generating the new

Please see 
http://docs.openstack.org/developer/horizon/topics/tutorial.html for some


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