docs: Update following container promotion changes

docs/usage/content-howto.md

@@ -7,23 +7,45 @@ That is the aim of this page.
 
 Update one or more package repositories to a new version, then build new Kolla container images from those repositories.
 
+If using Yoga release or earlier:
+
+* [Sync package repositories](content-workflows.md#syncing-package-repositories) (optional: runs nightly as a scheduled GitHub Action)
+* [Update Kayobe repository versions](content-workflows.md#updating-package-repository-versions-in-kayobe-configuration)
+* [Build & push Kolla container images](content-workflows.md#building-container-images)
+* [Update Kayobe container image tags](content-workflows.md#updating-container-image-tags-in-kayobe-configuration-yoga-release-and-earlier)
+* Test
+* Review & merge Kayobe configuration changes
+* [Promote container images](content-workflows.md#promoting-container-images-yoga-release-and-earlier)
+
+If using Zed release onwards:
+
 * [Sync package repositories](content-workflows.md#syncing-package-repositories) (optional: runs nightly as a scheduled GitHub Action)
 * [Update Kayobe repository versions](content-workflows.md#updating-package-repository-versions-in-kayobe-configuration)
 * [Build & push Kolla container images](content-workflows.md#building-container-images)
-* [Update Kayobe container image tags](content-workflows.md#updating-container-image-tags-in-kayobe-configuration)
+* [Update Kayobe container image tags](content-workflows.md#updating-container-image-tags-in-kayobe-configuration-zed-release-onwards)
 * Test
 * Review & merge Kayobe configuration changes
-* [Promote container images](content-workflows.md#promoting-container-images)
+* [Promote container images](content-workflows.md#promoting-container-images-zed-release-onwards)
 
 ## Update Kolla container images
 
 Update one or more Kolla container images, without updating package repositories.
 
+If using Yoga release or earlier:
+
+* [Build & push Kolla container images](content-workflows.md#building-container-images)
+* [Update Kayobe container image tags](content-workflows.md#updating-container-image-tags-in-kayobe-configuration-yoga-release-and-earlier)
+* Test
+* Review & merge Kayobe configuration changes
+* [Promote container images](content-workflows.md#promoting-container-images-yoga-release-and-earlier)
+
+If using Zed release onwards:
+
 * [Build & push Kolla container images](content-workflows.md#building-container-images)
-* [Update Kayobe container image tags](content-workflows.md#updating-container-image-tags-in-kayobe-configuration)
+* [Update Kayobe container image tags](content-workflows.md#updating-container-image-tags-in-kayobe-configuration-zed-release-onwards)
 * Test
 * Review & merge Kayobe configuration changes
-* [Promote container images](content-workflows.md#promoting-container-images)
+* [Promote container images](content-workflows.md#promoting-container-images-zed-release-onwards)
 
 ## Add a new Kolla container image
 

docs/usage/content-workflows.md

@@ -204,11 +204,7 @@ ansible/test-pulp-container-sync.yml \
 ansible/test-pulp-container-publish.yml
 ```
 
-## Updating container image tags in Kayobe configuration
-
-!!! note
-
-    This procedure is expected to change.
+## Updating container image tags in Kayobe configuration (Yoga release and earlier)
 
 The image tag used deploy containers may be updated for all images in [etc/kayobe/kolla.yml](https://github.com/stackhpc/stackhpc-kayobe-config/blob/stackhpc/wallaby/etc/kayobe/kolla.yml), or for specific images in [etc/kayobe/kolla/globals.yml](https://github.com/stackhpc/stackhpc-kayobe-config/blob/stackhpc/wallaby/etc/kayobe/kolla/globals.yml).
 Currently this is a manual process.
@@ -237,6 +233,55 @@ Alternatively, to update the tag for a specific container, update `etc/kayobe/ko
 skydive_analyzer_tag: wallaby-20220811T091848
 ```
 
+## Updating container image tags in Kayobe configuration (Zed release onwards)
+
+The image tags used deploy containers are defined in [etc/kayobe/kolla-image-tags.yml](https://github.com/stackhpc/stackhpc-kayobe-config/blob/stackhpc/zed/etc/kayobe/kolla-image-tags.yml).
+Currently updating these is a manual process.
+
+Use the new tag from the [container image build](#building-container-images).
+
+For example, to update the default tag for all images (used where no service-specific tag has been set), update the `openstack` key, and remove all other keys:
+
+```yaml
+# Dict of Kolla image tags to deploy for each service.
+# Each key is the tag variable prefix name, and the value is another dict,
+# where the key is the OS distro and the value is the tag to deploy.
+kolla_image_tags:
+  openstack:
+    rocky-9: zed-rocky-9-20230101T000000
+    ubuntu-jammy: zed-ubuntu-jammy-20230101T000000
+```
+
+Alternatively, update the tag for all containers in a service, e.g. for all `nova` containers:
+
+```yaml
+# Dict of Kolla image tags to deploy for each service.
+# Each key is the tag variable prefix name, and the value is another dict,
+# where the key is the OS distro and the value is the tag to deploy.
+kolla_image_tags:
+  openstack:
+    rocky-9: zed-rocky-9-20230101T000000
+    ubuntu-jammy: zed-ubuntu-jammy-20230101T000000
+  nova:
+    rocky-9: zed-rocky-9-20230102T000000
+    ubuntu-jammy: zed-ubuntu-jammy-20230102T000000
+```
+
+Alternatively, update the tag for a specific container, e.g. for the `nova_compute` container:
+
+```yaml
+# Dict of Kolla image tags to deploy for each service.
+# Each key is the tag variable prefix name, and the value is another dict,
+# where the key is the OS distro and the value is the tag to deploy.
+kolla_image_tags:
+  openstack:
+    rocky-9: zed-rocky-9-20230101T000000
+    ubuntu-jammy: zed-ubuntu-jammy-20230101T000000
+  nova_compute:
+    rocky-9: zed-rocky-9-20230103T000000
+    ubuntu-jammy: zed-ubuntu-jammy-20230103T000000
+```
+
 ## Promoting container images (Zed release onwards)
 
 !!! note