Overview

This charm provides Keystone, the Openstack identity service. It's target platform is (ideally) Ubuntu LTS + Openstack.

Usage

The following interfaces are provided:

- nrpe-external-master: Used to generate Nagios checks.

- identity-service: Openstack API endpoints request an entry in the 
  Keystone service catalog + endpoint template catalog. When a relation
  is established, Keystone receives: service name, region, public_url,
  admin_url and internal_url. It first checks that the requested service
  is listed as a supported service. This list should stay updated to
  support current Openstack core services. If the service is supported,
  an entry in the service catalog is created, an endpoint template is
  created and a admin token is generated. The other end of the relation
  receives the token as well as info on which ports Keystone is listening
  on.

- keystone-service: This is currently only used by Horizon/dashboard
  as its interaction with Keystone is different from other Openstack API
  services. That is, Horizon requests a Keystone role and token exists.
  During a relation, Horizon requests its configured default role and
  Keystone responds with a token and the auth + admin ports on which
  Keystone is listening.

- identity-admin: Charms use this relation to obtain the credentials
  for the admin user. This is intended for charms that automatically
  provision users, tenants, etc. or that otherwise automate using the
  Openstack cluster deployment.

- identity-notifications: Used to broadcast messages to any services
  listening on the interface.

Database

Keystone requires a database. By default, a local sqlite database is used. The charm supports relations to a shared-db via mysql-shared interface. When a new data store is configured, the charm ensures the minimum administrator credentials exist (as configured via charm configuration)

HA/Clustering

VIP is only required if you plan on multi-unit clustering (requires relating with hacluster charm). The VIP becomes a highly-available API endpoint.

SSL/HTTPS

This charm also supports SSL and HTTPS endpoints. In order to ensure SSL certificates are only created once and distributed to all units, one unit gets elected as an ssl-cert-master. One side-effect of this is that as units are scaled-out the currently elected leader needs to be running in order for nodes to sync certificates. This 'feature' is to work around the lack of native leadership election via Juju itself, a feature that is due for release some time soon but until then we have to rely on this. Also, if a keystone unit does go down, it must be removed from Juju i.e.

juju destroy-unit keystone/<unit-num>

Otherwise it will be assumed that this unit may come back at some point and therefore must be know to be in-sync with the rest before continuing.