overcloud-prep-images: install ara on mistral executor only when needed

Only install ara on mistral executor container if
undercloud_enable_mistral is set to True, otherwise we obviously don't
want it.

Move undercloud_enable_mistral to extras-common so it can be used by
both overcloud-prep-images and undercloud-deploy roles.

Change-Id: I69073b007138d8941da878def7033ffaf79e8f5d

roles/extras-common/README.md

@@ -46,3 +46,5 @@ Role Variables
 - `baremetal_provision`: <false> Deploy baremetal with "openstack overcloud node provision" and deployed-server, instead of with heat/nova
 - `undercloud_enable_nova`: <true> -- sets up the 'enable_nova'
   option in undercloud.conf.
+- `undercloud_enable_mistral`: <'true'> -- sets up the 'enable_mistral' option
+  in undercloud.conf for the undercloud and install ara in the mistral executor container before deploying the overcloud.

roles/extras-common/defaults/main.yml

@@ -104,3 +104,5 @@ octavia_amphora_path: >-
   {%- else -%}
   {{ working_dir }}/amphora.qcow2
   {%- endif %}
+
+undercloud_enable_mistral: true

roles/overcloud-prep-images/templates/overcloud-prep-images.sh.j2

@@ -222,7 +222,7 @@ sudo kill $pidof_tcpdump
 
 {% endif %}
 
-{% if release not in ['newton', 'ocata', 'pike', 'queens', 'rocky'] %}
+{% if release not in ['newton', 'ocata', 'pike', 'queens', 'rocky'] and undercloud_enable_mistral|bool %}
 container_cli="{{ undercloud_container_cli | default('podman') }}"
 cont=$(sudo $container_cli ps | grep executor | awk {'print $1'})
 sudo $container_cli exec --user root $cont bash -c "easy_install pip && pip install 'ara==1.0.0' || pip3 install 'ara==1.0.0'"

roles/undercloud-deploy/README.md

@@ -41,8 +41,6 @@ https://docs.openstack.org/tripleo-quickstart/latest/accessing-libvirt.html
 - `undercloud_extra_args`: <''> -- extra options for undercloud deploy command.
 - `undercloud_install_cmd`: <'openstack undercloud install'> -- command used to install the undercloud
 - `undercloud_install_cli_options`: <''> -- extra options for undercloud install command.
-- `undercloud_enable_mistral`: <'true'> -- sets up the 'enable_mistral' option
-  in undercloud.conf.
 - `undercloud_enable_monitoring`: <'false'> -- sets up the 'enable_monitoring'
   option in undercloud.conf.
 - `undercloud_enable_telemetry`: <'true'> -- sets up the 'enable_telemetry'

roles/undercloud-deploy/defaults/main.yml

@@ -55,7 +55,6 @@ virthost_nameservers: []
 
 undercloud_enable_ironic: true
 undercloud_enable_ironic_inspector: true
-undercloud_enable_mistral: true
 undercloud_enable_monitoring: false
 undercloud_enable_telemetry: false
 undercloud_enable_tempest: false