diff --git a/handlers/main.yml b/handlers/main.yml
index 6bd2af2c..12c9a35a 100644
--- a/handlers/main.yml
+++ b/handlers/main.yml
@@ -86,4 +86,4 @@
   retries: 5
   delay: 2
   when:
-    - inventory_hostname in groups['nova_api_placement']
+    - "'nova_api_placement' in group_names"
diff --git a/releasenotes/notes/nova-data-migrations-f6c2bc0f9e7b1908.yaml b/releasenotes/notes/nova-data-migrations-f6c2bc0f9e7b1908.yaml
new file mode 100644
index 00000000..0724c27e
--- /dev/null
+++ b/releasenotes/notes/nova-data-migrations-f6c2bc0f9e7b1908.yaml
@@ -0,0 +1,9 @@
+---
+features:
+  - The ``os_nova`` role now provides for doing
+    online data migrations once the db sync has
+    been completed. The data migrations will not
+    be executed until the boolean variable
+    ``nova_all_software_updated`` is true. This
+    variable will need to be set by the playbook
+    consuming the role.
diff --git a/tasks/main.yml b/tasks/main.yml
index 6b653792..27d0a7e9 100644
--- a/tasks/main.yml
+++ b/tasks/main.yml
@@ -49,13 +49,22 @@
   tags:
     - nova-install
 
+- name: refresh local facts
+  setup:
+    filter: ansible_local
+    gather_subset: "!all"
+  tags:
+    - nova-config
+
 - include: nova_post_install.yml
   tags:
     - nova-config
 
 - include: nova_db_setup.yml
+  static: no
   when:
-    - inventory_hostname == groups['nova_api_os_compute'][0]
+    - "'nova_conductor' in group_names"
+    - "inventory_hostname == ansible_play_hosts[0]"
   tags:
     - nova-config
 
@@ -64,29 +73,44 @@
     - nova-config
 
 - include: nova_service_setup.yml
+  static: no
   when:
-    - inventory_hostname == groups['nova_api_os_compute'][0]
+    - "'nova_conductor' in group_names"
+    - "inventory_hostname == ansible_play_hosts[0]"
   tags:
     - nova-config
 
 - include: nova_placement.yml
+  static: no
   when:
-    - nova_placement_service_enabled | bool
-    - inventory_hostname in groups['nova_api_placement']
+    - "nova_placement_service_enabled | bool"
+    - "'nova_api_placement' in group_names"
   tags:
     - nova-placement
 
 - include: nova_compute.yml
+  static: no
   when:
-    - inventory_hostname in groups['nova_compute']
+    - "'nova_compute' in group_names"
   tags:
     - nova-compute
 
 - name: Flush handlers
   meta: flush_handlers
 
+# We have to delegate this back to the conductor
+# because the compute hosts do not have access to
+# the database connection string and therefore
+# cannot run nova-manage.
+# Also, we delegate this to a random host in the
+# conductor group in order to spread the load of
+# multiple forks across the group members.
 - include: nova_db_post_setup.yml
+  delegate_to: "{{ conductor_host }}"
+  with_random_choice: "{{ groups['nova_conductor'] }}"
+  loop_control:
+    loop_var: conductor_host
   when:
-    - inventory_hostname == groups['nova_api_os_compute'][0]
+    - "'nova_compute' in group_names"
   tags:
     - nova-config
diff --git a/tasks/nova_db_post_setup.yml b/tasks/nova_db_post_setup.yml
index 22ae9792..15e7a772 100644
--- a/tasks/nova_db_post_setup.yml
+++ b/tasks/nova_db_post_setup.yml
@@ -19,40 +19,18 @@
   become: yes
   become_user: "{{ nova_system_user_name }}"
   changed_when: false
-  tags:
-    - nova-db-setup
-    - nova-setup
-    - nova-command-bin
 
 # When upgrading we need to map existing instances to the new cell1
 # To do this we need the cell UUID.
 - name: Get UUID of new Nova Cell
-  shell: "{{ nova_bin }}/nova-manage --config-file /etc/nova/nova.conf cell_v2 list_cells | awk '/{{ nova_cell1_name }}/ {print $4}'"
+  shell: "{{ nova_bin }}/nova-manage cell_v2 list_cells | grep ' {{ nova_cell1_name }} '"
   become: yes
   become_user: "{{ nova_system_user_name }}"
-  when: "nova_cell1_create.rc == 0"
   register: cell1_uuid
-  tags:
-    - nova-db-setup
-    - nova-setup
-    - nova-command-bin
+  changed_when: false
 
 - name: Map instances to new Cell1
-  command: "{{ nova_bin }}/nova-manage --config-file /etc/nova/nova.conf cell_v2 map_instances --cell_uuid {{ cell1_uuid.stdout }}"
-  become: yes
-  become_user: "{{ nova_system_user_name }}"
-  when: "nova_cell1_create.rc == 0"
-  tags:
-    - nova-db-setup
-    - nova-setup
-    - nova-command-bin
-
-- name: Perform Nova online data migrations
-  command: "{{ nova_bin }}/nova-manage --config-file /etc/nova/nova.conf db online_data_migrations"
+  command: "{{ nova_bin }}/nova-manage cell_v2 map_instances --cell_uuid {{ cell1_uuid['stdout'].split()[3] }}"
   become: yes
   become_user: "{{ nova_system_user_name }}"
   changed_when: false
-  tags:
-    - nova-db-setup
-    - nova-setup
-    - nova-command-bin
diff --git a/tasks/nova_db_setup.yml b/tasks/nova_db_setup.yml
index 662c5b3c..cc19ac73 100644
--- a/tasks/nova_db_setup.yml
+++ b/tasks/nova_db_setup.yml
@@ -19,32 +19,20 @@
   become_user: "{{ nova_system_user_name }}"
   register: nova_api_db_version
   changed_when: false
-  tags:
-    - nova-db-setup
-    - nova-setup
-    - nova-command-bin
 
 - name: Perform a Nova API DB sync
-  command: "{{ nova_bin }}/nova-manage --config-file /etc/nova/nova.conf api_db sync"
+  command: "{{ nova_bin }}/nova-manage api_db sync"
   become: yes
   become_user: "{{ nova_system_user_name }}"
   changed_when: false
   when:
     - nova_api_db_version.stdout == "0"
-  tags:
-    - nova-db-setup
-    - nova-setup
-    - nova-command-bin
 
 - name: Perform cell_v2 map cell0
   command: "{{ nova_bin }}/nova-manage cell_v2 map_cell0 --database_connection mysql+pymysql://{{ nova_api_galera_user }}:{{ nova_api_container_mysql_password }}@{{ nova_api_galera_address }}/{{ nova_cell0_database }}?charset=utf8"
   become: yes
   become_user: "{{ nova_system_user_name }}"
   changed_when: false
-  tags:
-    - nova-db-setup
-    - nova-setup
-    - nova-command-bin
 
 - name: Perform cell_v2 initial cell setup
   command: "{{ nova_bin }}/nova-manage cell_v2 create_cell --name {{ nova_cell1_name }} --database_connection mysql+pymysql://{{ nova_galera_user }}:{{ nova_container_mysql_password }}@{{ nova_galera_address }}/{{ nova_galera_database }}?charset=utf8 --transport-url rabbit://{% for host in nova_rabbitmq_servers.split(',') %}{{ nova_rabbitmq_userid }}:{{ nova_rabbitmq_password }}@{{ host }}:{{ nova_rabbitmq_port }}{% if not loop.last %},{% else %}/{{ nova_rabbitmq_vhost }}{% endif %}{% endfor %}"
@@ -53,27 +41,34 @@
   register: nova_cell1_create
   failed_when: "nova_cell1_create.rc not in [0, 2]"
   changed_when: "nova_cell1_create.rc == 0"
-  tags:
-    - nova-db-setup
-    - nova-setup
-    - nova-command-bin
 
 - name: Perform a Nova API DB sync
-  command: "{{ nova_bin }}/nova-manage --config-file /etc/nova/nova.conf api_db sync"
+  command: "{{ nova_bin }}/nova-manage api_db sync"
   become: yes
   become_user: "{{ nova_system_user_name }}"
   changed_when: false
-  tags:
-    - nova-db-setup
-    - nova-setup
-    - nova-command-bin
 
 - name: Perform a Nova DB sync
-  command: "{{ nova_bin }}/nova-manage --config-file /etc/nova/nova.conf db sync"
+  command: "{{ nova_bin }}/nova-manage db sync"
   become: yes
   become_user: "{{ nova_system_user_name }}"
   changed_when: false
-  tags:
-    - nova-db-setup
-    - nova-setup
-    - nova-command-bin
+
+- name: Perform online data migrations
+  command: "{{ nova_bin }}/nova-manage db online_data_migrations"
+  become: yes
+  become_user: "{{ nova_system_user_name }}"
+  when:
+    - "(nova_all_software_updated | default('no')) | bool"
+    - "ansible_local['openstack_ansible']['nova']['need_online_data_migrations'] | bool"
+  changed_when: false
+  register: data_migrations
+
+- name: Disable the online migrations requirement
+  ini_file:
+    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
+    section: nova
+    option: need_online_data_migrations
+    value: False
+  when:
+    - data_migrations | succeeded
diff --git a/tasks/nova_install.yml b/tasks/nova_install.yml
index 38d1c7d2..1a75f9bf 100644
--- a/tasks/nova_install.yml
+++ b/tasks/nova_install.yml
@@ -165,6 +165,25 @@
     - nova-novnc-console
     - nova-spice-console
 
+- name: Initialise the upgrade facts
+  ini_file:
+    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
+    section: nova
+    option: "{{ item }}"
+    value: True
+  with_items:
+    - "need_service_restart"
+    - "need_online_data_migrations"
+  when:
+    - (nova_get_venv | changed) or
+      (nova_venv_dir | changed) or
+      (install_packages | changed) or
+      (ansible_local is not defined) or
+      ('openstack_ansible' not in ansible_local) or
+      ('nova' not in ansible_local['openstack_ansible']) or
+      ('need_online_data_migrations' not in ansible_local['openstack_ansible']['nova']) or
+      ('need_service_restart' not in ansible_local['openstack_ansible']['nova'])
+
 - name: Record the venv tag deployed
   ini_file:
     dest: "/etc/ansible/facts.d/openstack_ansible.fact"
diff --git a/templates/nova.conf.j2 b/templates/nova.conf.j2
index 2db262c9..9cd77e6f 100644
--- a/templates/nova.conf.j2
+++ b/templates/nova.conf.j2
@@ -324,3 +324,6 @@ metadata_items = {{ nova_quota_metadata_items }}
 ram = {{ nova_quota_ram }}
 server_group_members = {{ nova_quota_server_group_members }}
 server_groups = {{ nova_quota_server_groups }}
+
+[upgrade_levels]
+compute=auto