Automatically enable the cinder backup service

This patch implements an automated determination of whether the
cinder backup service should be enabled based on whether there
are swift hosts in the environment.

This reduces the number of variables a deployer needs to set in
order to have a functional environment.

Change-Id: I0fd9afea9e962b61d255b86ba894afb96e84e58f

playbooks/inventory/group_vars/all.yml

@@ -117,6 +117,8 @@ ceilometer_rabbitmq_host_group: "rabbitmq_all"
 ceilometer_rabbitmq_port: "{{ rabbitmq_port }}"
 
 ## Cinder
+# If there are Swift hosts in the environment, then enable cinder backups to it
+cinder_service_backup_program_enabled: "{{ groups['swift_all'] is defined and groups['swift_all'] | length > 0 }}"
 # cinder_backend_rbd_inuse: True if current host has an rbd backend
 cinder_backend_rbd_inuse: '{{ (cinder_backends|default("")|to_json).find("cinder.volume.drivers.rbd.RBDDriver") != -1 }}'
 # cinder_backends_rbd_inuse: true if at least 1 cinder_backend on any

playbooks/inventory/group_vars/utility_all.yml

@@ -21,5 +21,8 @@ tempest_log_dir: /var/log/utility
 
 galera_client_drop_config_file: true
 
+# If cinder has a backup service enabled, make sure that Tempest tests it
+tempest_volume_backup_enabled: "{{ cinder_service_backup_program_enabled | bool }}"
+
 # Ensure that the package state matches the global setting
 utility_package_state: "{{ package_state }}"

releasenotes/notes/detect-cinder-backup-service-7dc68f532741be87.yaml

@@ -0,0 +1,13 @@
+---
+features:
+  - If there are swift hosts in the environment, then the value for
+    ``cinder_service_backup_program_enabled`` will automatically be
+    set to ``True``. This negates the need to set this variable in
+    ``user_variables.yml``, but the value may still be overridden at
+    the deployer discretion.
+upgrade:
+  - If there are swift hosts in the environment, then the value for
+    ``cinder_service_backup_program_enabled`` will automatically be
+    set to ``True``. This negates the need to set this variable in
+    ``user_variables.yml``, but the value may still be overridden at
+    the deployer discretion.

tests/roles/bootstrap-host/templates/user_variables.aio.yml.j2

@@ -16,15 +16,11 @@
 ## General options
 debug: True
 
-## Cinder settings
-cinder_service_backup_program_enabled: True
-
 ## Tempest settings
 tempest_service_available_ceilometer: True
 tempest_service_available_aodh: True
 tempest_public_subnet_cidr: 172.29.248.0/22
 tempest_public_subnet_allocation_pools: "172.29.249.110-172.29.249.200"
-tempest_volume_backup_enabled: True
 
 ## Galera settings
 galera_innodb_buffer_pool_size: 512M