Allow Horizon to access multiple regions

This patch introduces the capability for Horizon to access
multiple regions.

This only takes effect if horizon_available_regions is defined,
otherwise the current default comment is applied to the
local_settings file.

Usage is described via comments in the role defaults and in the
etc/openstack_deploy/user_variables.yml file.

Change-Id: Ia8c0b8be67fd0f479c492d9919b542806f9b204f

etc/openstack_deploy/user_variables.yml

@@ -88,3 +88,11 @@ ssl_cipher_suite: "ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AE
 #   HTTP_PROXY: "{{ proxy_env_url }}"
 #   HTTPS_PROXY: "{{ proxy_env_url }}"
 #   NO_PROXY: "{{ no_proxy_env }}"
+
+
+## Multiple region support in Horizon:
+# For multiple regions uncomment this configuration, and
+# add the extra endpoints below the first list item.
+# horizon_available_regions:
+#   - { url: "{{ keystone_service_internalurl }}", name: "{{ keystone_service_region }}" }
+#   - { url: "http://cluster1.example.com:5000/v2.0", name: "RegionTwo" }

playbooks/roles/os_horizon/defaults/main.yml

@@ -67,6 +67,12 @@ horizon_ssl_cert_path: /etc/ssl/certs
 horizon_ssl_protocol: "{{ ssl_protocol }}"
 horizon_ssl_cipher_suite: "{{ ssl_cipher_suite }}"
 
+# For multiple regions uncomment this configuration, and
+# add the extra endpoints below the first list item.
+# horizon_available_regions:
+#   - { url: "{{ keystone_service_internalurl }}", name: "{{ keystone_service_region }}" }
+#   - { url: "http://cluster1.example.com:5000/v2.0", name: "RegionTwo" }
+
 ## Launch instance
 horizon_launch_instance_legacy: True
 horizon_launch_instance_ng: False

playbooks/roles/os_horizon/templates/horizon_local_settings.py.j2

@@ -155,11 +155,20 @@ EMAIL_BACKEND = 'django.core.mail.backends.console.EmailBackend'
 # EMAIL_HOST_USER = 'djangomail'
 # EMAIL_HOST_PASSWORD = 'top-secret!'
 
+{% if horizon_available_regions is defined %}
+# Set the regions accessible through Horizon
+AVAILABLE_REGIONS = [
+{% for item in horizon_available_regions %}
+  ('{{ item.url }}', '{{ item.name }}'),
+{% endfor %}
+]
+{% else %}
 # For multiple regions uncomment this configuration, and add (endpoint, title).
 # AVAILABLE_REGIONS = [
 #     ('http://cluster1.example.com:5000/v2.0', 'cluster1'),
 #     ('http://cluster2.example.com:5000/v2.0', 'cluster2'),
 # ]
+{% endif %}
 
 OPENSTACK_HOST = "{{ internal_lb_vip_address }}"
 OPENSTACK_KEYSTONE_URL = "{{ keystone_service_internalurl }}"