--- title: Resolve overlapping index templates for namespace customization description: Resolve overlapping index templates when you enable namespace index templates for a Fleet integration. url: https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/7705/reference/fleet/data-streams-template-conflicts products: - Elastic Agent - Fleet applies_to: - Elastic Cloud Serverless: Generally available - Elastic Stack: Planned --- # Resolve overlapping index templates for namespace customization Learn how to interpret and resolve warnings about overlapping index templates when you enable [namespace index templates](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/7705/reference/fleet/data-streams-namespace-custom) for a Fleet integration. This page helps you decide whether to keep your existing customizations, switch to Fleet-managed namespace index templates, or combine both approaches. ## When overlapping templates appear If you previously duplicated an integration's base data stream index template (priority `200`), narrowed the index pattern to one namespace, and raised the copy's priority (often to `250` or higher), that copy can overlap with a Fleet-managed namespace index template. For example, you might have copied `logs-nginx.error` into `logs-nginx.error-production-custom` with pattern `logs-nginx.error-production*` and priority `280`. When you enable namespace index templates for that same namespace, Fleet tries to create a managed template such as `logs-nginx.error@namespace.production` at priority `250` for the same index pattern. Elasticsearch applies only one winning index template per index creation, so those templates overlap. The result depends on the existing template's priority, as described in [How Fleet detects and reports overlaps](#data-streams-template-conflicts-detect). The same can happen with any pre-existing index template whose index patterns match the namespace's data streams, not only copies with a custom suffix in the name. ## How Fleet detects and reports overlaps When you enable namespace index templates for a namespace on an integration, Fleet runs a preflight check for each `(data stream, namespace)` pair. The check uses the Elasticsearch simulate index API (`POST _index_template/_simulate_index/`) to see which existing template would win for that data stream, then compares priorities with the planned namespace index template. Fleet sets the namespace index template priority to the base template priority plus 50: `250` for most integrations (base `200`), or `200` for integrations with `dataset_is_prefix: true` data streams (base `150`). The examples on this page use `250`; if your integration uses `dataset_is_prefix` data streams, read `200` instead. A user with the `manage_index_templates` privilege can change this priority with the Elasticsearch index template API, but Fleet restores the default whenever the integration's templates are reinstalled or resynchronized. Fleet reports overlaps in the UI before changes are applied, and in API responses as warnings. Each overlap falls into one of these cases: | Situation | What happens | |-------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | Existing template priority is higher than `250` | Fleet creates the namespace index template, but Elasticsearch applies the existing template for new data streams. The namespace index template's `composed_of` chain (including `@custom`) is not used. | | Existing template priority is exactly `250` | Fleet cannot create the namespace index template. The existing template continues to govern new data streams for that pair until you change priorities and enable namespace index templates again. | | Existing template priority is lower than `250` | Fleet creates the namespace index template, and Elasticsearch applies it for new data streams. The existing template no longer affects newly created indices in that namespace. | Index templates are applied when backing indices are created. Existing indices are not rewritten when you enable or turn off namespace index templates. Elasticsearch does not merge overlapping index templates. The highest-priority matching template wins as a whole. Component templates are merged only within that winning template's `composed_of` list. ## Choose a resolution path Pick the path that matches your goal. ### Use Fleet-managed namespace index templates Use this path when you want `@custom` and related Fleet namespace features to apply. 1. Identify overlapping templates in **Index Management** → **Index Templates**. Look for templates whose index patterns match the same data streams as the planned `@namespace.` templates. 2. If any overlapping template has priority `250`, lower that priority (for example to `200` or less) or remove the template before enabling. Same-priority templates block creation of the Fleet-managed namespace index template. 1. Go to the **Index Management** page using the navigation menu or the [global search field](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/7705/explore-analyze/find-and-organize/find-apps-and-objects), and open the **Index Templates** tab. 2. Find and select the index template you want to change, then select **Manage** → **Edit**. 3. On the **Logistics** step, update the **Priority** value. 4. Continue to the **Review** step, then save the template. For more about creating and managing index templates, refer to [Index templates](/elastic/docs-content/pull/7705/manage-data/data-store/templates#index-templates). 3. Enable namespace index templates for the namespace. For UI and API steps, refer to [Customize data streams with namespace index templates](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/7705/reference/fleet/data-streams-namespace-custom). 4. Confirm the managed templates exist (for example, search index templates for `@namespace.`). 5. Create or update the `@custom` component template with the settings you still need. Copy useful settings from your older custom index templates into `@custom` or into the data stream `@custom` templates when they should stay data-stream-specific. 6. Optionally delete or further lower the priority of unused custom index templates that no longer win, if you don't need them as a fallback. 7. Roll over each affected data stream so new backing indices use the managed templates. If you enabled namespace index templates while a priority-`250` overlap blocked some templates, turn them off for that namespace, adjust those priorities, then enable them again so Fleet can create the missing namespace index templates. ### Keep your existing custom index templates Use this path when your custom index templates already do what you need. 1. Cancel enabling if the warning appears in the UI, or leave the namespace out of **Namespaces with dedicated index templates**. 2. If you already enabled namespace index templates for the namespace, remove it from **Namespaces with dedicated index templates** on the integration's **Settings** tab, or turn off **Use dedicated index templates for this namespace** in the integration policy editor. Fleet deletes the managed namespace index templates; your existing templates remain. 3. Continue managing customization through your existing index templates and component templates. ### Combine both approaches Use this path only when you understand which template should win for each data stream. 1. Review every overlapping template's priority against the namespace index template priority (`250` for most integrations; refer to the preceding note). 2. For data streams where your custom template must win, set its priority higher than the namespace index template priority. For data streams where the Fleet-managed namespace index template must win, set your custom template's priority lower (but not equal, which blocks creation), or remove the template. 1. Go to the **Index Management** page using the navigation menu or the [global search field](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/7705/explore-analyze/find-and-organize/find-apps-and-objects), and open the **Index Templates** tab. 2. Find and select the index template you want to change, then select **Manage** → **Edit**. 3. On the **Logistics** step, update the **Priority** value. 4. Continue to the **Review** step, then save the template. For more about creating and managing index templates, refer to [Index templates](/elastic/docs-content/pull/7705/manage-data/data-store/templates#index-templates). 3. Enable namespace index templates and read the warning list to confirm the expected winners. 4. Verify a sample of new backing indices (settings, mappings, and lifecycle) after rollover. Leaving overlapping templates at priority `250` or higher means some or all namespace index template customization might be unused or incomplete, even after you enable the feature. ## Related pages - [Customize data streams with namespace index templates](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/7705/reference/fleet/data-streams-namespace-custom) - [Edit the Elasticsearch index template](/elastic/docs-content/pull/7705/reference/fleet/data-streams#data-streams-index-templates-edit) - [Best practices for copying an integration index template](/elastic/docs-content/pull/7705/reference/fleet/integrations-assets-best-practices#assets-restrictions-cloning-index-template) - [Tutorials: Customize data retention policies](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/7705/reference/fleet/data-streams-ilm-tutorial)