Add Scenario 4: Apply ILM policy to all data streams in a custom integration (elastic#2082)

Added a new ILM configuration scenario to the Fleet data streams
documentation (Scenario 4: Apply an ILM policy to all data streams in a
custom integration).

Applies to version 9.1 and later

Author: alexandra5000

reference/fleet/data-streams-ilm-tutorial.md

@@ -26,4 +26,5 @@ How you apply an ILM policy depends on your use case. Choose a scenario for the
 
 * **[Scenario 1](/reference/fleet/data-streams-scenario1.md)**: You want to apply an ILM policy to all logs or metrics data streams across all namespaces.
 * **[Scenario 2](/reference/fleet/data-streams-scenario2.md)**: You want to apply an ILM policy to selected data streams in an integration.
-* **[Scenario 3](/reference/fleet/data-streams-scenario3.md)**: You want apply an ILM policy for data streams in a selected namespace in an integration.
+* **[Scenario 3](/reference/fleet/data-streams-scenario3.md)**: You want to apply an ILM policy for data streams in a selected namespace in an integration.
+* **[Scenario 4](/reference/fleet/data-streams-scenario4.md)**: You want to apply an ILM policy to all data streams in a custom integration using a `@custom` component template. {applies_to}`stack: ga 9.1`

reference/fleet/data-streams-scenario4.md

@@ -0,0 +1,58 @@
+---
+navigation_title: Scenario 4
+mapped_pages:
+  - https://www.elastic.co/guide/en/fleet/current/data-streams-scenario4.html
+products:
+  - id: fleet
+  - id: elastic-agent
+applies_to:
+  stack: ga 9.1
+  serverless: ga
+---
+
+# Scenario 4: Apply an ILM policy to all data streams in a custom integration [data-streams-scenario4]
+
+If you’ve created a custom integration package, you can apply a single ILM policy to all its data streams using a shared `@custom` component template. This eliminates the need to configure each data stream individually.
+
+## Step 1: Define the ILM policy [data-streams-scenario4-step1]
+
+1. In {{kib}}, go to **Stack Management** and select **Index Lifecycle Policies**. You can also use the [global search field](/get-started/the-stack.md#kibana-navigation-search).
+2. Click **Create policy**.
+3. Name the policy, configure it as needed, and click **Save policy**.
+
+## Step 2: Create a custom component template [data-streams-scenario4-step2]
+
+Create a custom component template named `<integration>@custom`, replacing `<integration>` with your package name.
+
+For example, for a Docker integration, use:
+
+```json
+PUT _component_template/docker@custom
+{
+  "template": {
+    "settings": {
+      "index": {
+        "lifecycle": {
+          "name": "docker-ilm-policy"
+        }
+      }
+    },
+    "mappings": {
+      "properties":
+      }
+    }
+  }
+}
+```
+
+## Step 3: Deploy or update the integration [data-streams-scenario4-step3]
+
+The `@custom` component template is automatically included when the package is installed or updated.
+
+To apply the ILM policy:
+
+- Bump the version of your custom package.
+
+- Reinstall or upgrade the package using the {{fleet}} UI or Developer Console.
+
+After the ILM policy from `docker` has been deployed, it applies to all data streams in the package.

reference/fleet/toc.yml

@@ -151,6 +151,7 @@ toc:
           - file: data-streams-scenario1.md
           - file: data-streams-scenario2.md
           - file: data-streams-scenario3.md
+          - file: data-streams-scenario4.md
           - file: data-streams-pipeline-tutorial.md
           - file: data-streams-advanced-features.md
   - file: agent-command-reference.md