[8.18] [Fleet] Never delete @custom component templates (#214232) (#214289)

# Backport

This will backport the following commits from `main` to `8.18`:
- [[Fleet] Never delete @custom component templates
(#214232)](https://github.com/elastic/kibana/pull/214232)

<!--- Backport version: 9.6.6 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sorenlouv/backport)

<!--BACKPORT [{"author":{"name":"Nicolas
Chaulet","email":"nicolas.chaulet@elastic.co"},"sourceCommit":{"committedDate":"2025-03-12T19:58:40Z","message":"[Fleet]
Never delete @custom component templates
(#214232)","sha":"fc64501577284038eef59bb8fc37ea4d80b49827","branchLabelMapping":{"^v9.1.0$":"main","^v8.19.0$":"8.x","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:skip","Team:Fleet","v9.0.0","backport:prev-minor","backport:version","v9.1.0","backport:8.18","v8.18.1"],"title":"[Fleet]
Never delete @custom component
templates","number":214232,"url":"https://github.com/elastic/kibana/pull/214232","mergeCommit":{"message":"[Fleet]
Never delete @custom component templates
(#214232)","sha":"fc64501577284038eef59bb8fc37ea4d80b49827"}},"sourceBranch":"main","suggestedTargetBranches":["8.18"],"targetPullRequestStates":[{"branch":"9.0","label":"v9.0.0","branchLabelMappingKey":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"url":"https://github.com/elastic/kibana/pull/214279","number":214279,"state":"MERGED","mergeCommit":{"sha":"ffc575724f73009d5d564b7c896ab162e7880c4e","message":"[9.0]
[Fleet] Never delete @custom component templates (#214232)
(#214279)\n\n# Backport\n\nThis will backport the following commits from
`main` to `9.0`:\n- [[Fleet] Never delete @custom component
templates\n(#214232)](https://github.com/elastic/kibana/pull/214232)\n\n\n\n###
Questions ?\nPlease refer to the [Backport
tool\ndocumentation](https://github.com/sorenlouv/backport)\n\n\n\nCo-authored-by:
Nicolas Chaulet
<nicolas.chaulet@elastic.co>"}},{"branch":"main","label":"v9.1.0","branchLabelMappingKey":"^v9.1.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/214232","number":214232,"mergeCommit":{"message":"[Fleet]
Never delete @custom component templates
(#214232)","sha":"fc64501577284038eef59bb8fc37ea4d80b49827"}},{"branch":"8.18","label":"v8.18.1","branchLabelMappingKey":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

---------

Co-authored-by: Nicolas Chaulet <nicolas.chaulet@elastic.co>

x-pack/platform/plugins/shared/fleet/server/services/epm/elasticsearch/template/remove_legacy.ts

@@ -11,6 +11,7 @@ import type {
 } from '@elastic/elasticsearch/lib/api/types';
 import type { ElasticsearchClient, Logger } from '@kbn/core/server';
 
+import { USER_SETTINGS_TEMPLATE_SUFFIX } from '../../../../../common/constants';
 import type { InstallablePackage, RegistryDataStream } from '../../../../types';
 import { getRegistryDataStreamAssetBaseName } from '../../../../../common/services';
 const LEGACY_TEMPLATE_SUFFIXES = ['@mappings', '@settings'];
@@ -108,6 +109,9 @@ export const _filterComponentTemplatesInUse = ({
   const usedByLookup = _getIndexTemplatesToUsedByMap(indexTemplates);
 
   return componentTemplateNames.filter((componentTemplateName) => {
+    if (componentTemplateName.endsWith(USER_SETTINGS_TEMPLATE_SUFFIX)) {
+      return false;
+    }
     const indexTemplatesUsingComponentTemplate = usedByLookup.get(componentTemplateName);
 
     if (indexTemplatesUsingComponentTemplate?.length) {

x-pack/platform/plugins/shared/fleet/server/services/epm/packages/remove.test.ts

@@ -4,13 +4,14 @@
  * 2.0; you may not use this file except in compliance with the Elastic License
  * 2.0.
  */
+import { elasticsearchServiceMock } from '@kbn/core/server/mocks';
 
-import { PACKAGES_SAVED_OBJECT_TYPE } from '../../../../common';
+import { ElasticsearchAssetType, PACKAGES_SAVED_OBJECT_TYPE } from '../../../../common';
 
 import { packagePolicyService } from '../..';
 import { auditLoggingService } from '../../audit_logging';
 
-import { removeInstallation } from './remove';
+import { deleteESAssets, removeInstallation } from './remove';
 
 jest.mock('../..', () => {
   return {
@@ -111,3 +112,38 @@ describe('removeInstallation', () => {
     });
   });
 });
+
+describe('deleteESAssets', () => {
+  it('should not delete @custom components template', async () => {
+    const esClient = elasticsearchServiceMock.createInternalClient();
+    await deleteESAssets(
+      [
+        {
+          id: 'logs@custom',
+          type: ElasticsearchAssetType.componentTemplate,
+        },
+      ],
+      esClient
+    );
+
+    expect(esClient.cluster.deleteComponentTemplate).not.toBeCalled();
+  });
+
+  it('should delete @package components template', async () => {
+    const esClient = elasticsearchServiceMock.createInternalClient();
+    await deleteESAssets(
+      [
+        {
+          id: 'logs-nginx.access@package',
+          type: ElasticsearchAssetType.componentTemplate,
+        },
+      ],
+      esClient
+    );
+
+    expect(esClient.cluster.deleteComponentTemplate).toBeCalledWith(
+      { name: 'logs-nginx.access@package' },
+      expect.anything()
+    );
+  });
+});

x-pack/platform/plugins/shared/fleet/server/services/epm/packages/remove.ts

@@ -24,6 +24,7 @@ import {
   PACKAGE_POLICY_SAVED_OBJECT_TYPE,
   PACKAGES_SAVED_OBJECT_TYPE,
   SO_SEARCH_LIMIT,
+  USER_SETTINGS_TEMPLATE_SUFFIX,
 } from '../../../constants';
 import { ElasticsearchAssetType } from '../../../types';
 import type {
@@ -368,7 +369,7 @@ async function deleteIndexTemplate(esClient: ElasticsearchClient, name: string):
 
 async function deleteComponentTemplate(esClient: ElasticsearchClient, name: string): Promise<void> {
   // '*' shouldn't ever appear here, but it still would delete all templates
-  if (name && name !== '*') {
+  if (name && name !== '*' && !name.endsWith(USER_SETTINGS_TEMPLATE_SUFFIX)) {
     try {
       await esClient.cluster.deleteComponentTemplate({ name }, { ignore: [404] });
     } catch (error) {