Improve Placement special operation

Improve the instructions that cover the introduction of the
placement charm by mentioning that nova-compute payload
upgrade should follow nova-cloud-controller payload upgrade.

Correct the payload upgrade order on the openstack-upgrade
page by putting nova-compute after nova-cloud-controller.
The former was recently moved up due to minimise OVN control
plane downtime but the current fix is essential.

The upgrdae-charms page was likewise updated.

Closes-Bug: #1970266
Change-Id: Ic564bfd649bd8d3ba435577b7e7d2f472992a1c6

deploy-guide/source/placement-charm-upgrade-to-train.rst

@@ -21,7 +21,7 @@ Here are example commands for the process just described:
 
 .. code-block:: none
 
-   juju deploy --series bionic --config openstack-origin=cloud:bionic-train placement
+   juju deploy --series bionic --config openstack-origin=cloud:bionic-train cs:placement
    juju run-action --wait nova-cloud-controller/leader pause
    juju add-relation placement percona-cluster
    juju add-relation placement keystone
@@ -43,6 +43,8 @@ method for a more controlled approach:
 
    juju config nova-cloud-controller openstack-origin=cloud:bionic-train
 
+The Compute service (nova-compute) should then be upgraded.
+
 .. LINKS
-.. _placement: https://jaas.ai/placement
+.. _placement: https://charmhub.io/placement
 .. _paused-single-unit: upgrade-openstack.html#paused-single-unit

deploy-guide/source/upgrade-charms.rst

@@ -112,14 +112,14 @@ table.
      - `ovn-central`_
 
    * - 21
-     - `nova-compute`_
-
-   * - 22
      - `placement`_
 
-   * - 23
+   * - 22
      - `nova-cloud-controller`_
 
+   * - 23
+     - `nova-compute`_
+
    * - 24
      - `openstack-dashboard`_
 

deploy-guide/source/upgrade-openstack.rst

@@ -325,14 +325,14 @@ along with those of the service being targeted.
      - `ovn-central`_
 
    * - 19
-     - `nova-compute`_
-
-   * - 20
      - `placement`_
 
-   * - 21
+   * - 20
      - `nova-cloud-controller`_
 
+   * - 21
+     - `nova-compute`_
+
    * - 22
      - `openstack-dashboard`_
 
@@ -348,11 +348,10 @@ along with those of the service being targeted.
    * - 26
      - `octavia`_
 
-.. note::
+.. important::
 
    The OVN control plane will not be available between the commencement of the
-   ovn-central upgrade and the completion of the nova-compute upgrade. They are
-   deliberately placed in close proximity to each other for this reason.
+   ovn-central upgrade and the completion of the nova-compute upgrade.
 
 Update the charm channel
 ------------------------