Run "nova-status upgrade check" during install and upgrade

This adds a task to run the 'nova-status upgrade check' command
post-install/upgrade after cells and placement setup is done and
online data migrations have been run.

This is generally used for verifying an upgrade once the control
services have been upgraded, nova API DB has been migrated and
online data migrations have been run, but is also good to run
post-install for greenfield deployments:

https://docs.openstack.org/nova/latest/install/verify.html

This is also an important tool for fast-forward upgrades to
make sure each release being forwarded through has been properly
upgraded before moving onto the next.

Change-Id: I73da0679563383d682a5f617b4a224d8f83a0523

tasks/main.yml

@@ -173,3 +173,26 @@
     first_conductor: "{{ groups[nova_services['nova-conductor']['group']][0] }}"
   tags:
     - nova-config
+
+# The nova-status upgrade check command is typically run after upgrading the
+# controller services to new code, but is also OK to run for a greenfield
+# install to verify everything is setup correctly. This must run after cell
+# mapping setup and online data migrations have run.
+# https://docs.openstack.org/nova/latest/cli/nova-status.html
+- name: Run nova-status
+  command: "{{ nova_bin }}/nova-status upgrade check"
+  become: yes
+  become_user: "{{ nova_system_user_name }}"
+  register: nova_status_upgrade_check
+  # The nova-status upgrade check command has three standard return codes:
+  # 0: all checks were successful
+  # 1: warning: there might be some checks that require investigation, but
+  #    generally will not block an automated install/upgrade; digging into
+  #    warnings is useful for debugging post-install/upgrade issues
+  # 2: at least one check failed and must stop the install/upgrade because
+  #    something was not setup properly
+  failed_when: "nova_status_upgrade_check.rc not in [0, 1]"
+  changed_when: false
+  when:
+    # Only run nova-status on controller nodes.
+    - "nova_services['nova-conductor']['group'] in group_names"