configuration-guide: custom horizon themes

Signed-off-by: Christian Berendt <[email protected]>

docs/guides/configuration-guide/openstack/horizon.md → docs/guides/configuration-guide/openstack/horizon.mdx

@@ -2,6 +2,9 @@
 sidebar_label: Horizon
 ---
 
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
 # Horizon
 
 * [Horizon admin guide](https://docs.openstack.org/horizon/latest/admin/index.html)
@@ -43,3 +46,34 @@ USER_MENU_LINKS = [
    }
 ]
 ```
+
+## Custom themes
+
+1. Place the files and directories of the custom theme in
+   `environments/kolla/files/overlays/horizon/themes/custom_theme`.
+   Examples of custom themes can be found in the [osism/openstack-themes](https://github.com/osism/openstack-themes)
+   repository.
+
+2. Add the custom theme to the `horizon_custom_themes` dictionary.
+
+   ```yaml title="environments/kolla/configuration.yml"
+   horizon_custom_themes:
+     - name: custom_theme
+       label: CustomTheme
+   ```
+
+3. If the custom theme should be the default them add the `DEFAULT_THEME` parameter.
+
+
+   <Tabs>
+   <TabItem value="osism-8" label="OSISM >= 8.0.0">
+   ```python title="environments/kolla/files/overlays/horizon/_9999-custom-settings.py"
+   DEFAULT_THEME = 'custom_theme'
+   ```
+   </TabItem>
+   <TabItem value="osism-8" label="OSISM < 8.0.0">
+   ```python title="environments/kolla/files/overlays/horizon/custom_local_settings"
+   DEFAULT_THEME = 'custom_theme'
+   ```
+   </TabItem>
+   </Tabs>

docs/release-notes/osism-8.md

@@ -55,6 +55,9 @@ Release date: 11. September 2024
   designate_enable_notifications_sink: "yes"
   ```
 
+* The file containing the custom local settings of Horizon has been renamed from
+  `custom_local_settings` to `_9999-custom-settings.py`.
+
 ### Other & References
 
 OpenStack 2024.1 press announcement: https://www.openstack.org/software/openstack-caracal