[Fleet] Rename config value agents.elasticsearch.host => agents.elasticsearch.hosts (#101162)

docs/settings/fleet-settings.asciidoc

@@ -39,8 +39,8 @@ See the {fleet-guide}/index.html[{fleet}] docs for more information.
 |===
 | `xpack.fleet.agents.fleet_server.hosts`
   | Hostnames used by {agent} for accessing {fleet-server}.
-| `xpack.fleet.agents.elasticsearch.host`
-  | The hostname used by {agent} for accessing {es}.
+| `xpack.fleet.agents.elasticsearch.hosts`
+  | Hostnames used by {agent} for accessing {es}.
 |===
 
 [NOTE]

x-pack/plugins/fleet/common/types/index.ts

@@ -16,7 +16,7 @@ export interface FleetConfigType {
   agents: {
     enabled: boolean;
     elasticsearch: {
-      host?: string;
+      hosts?: string[];
       ca_sha256?: string;
     };
     fleet_server?: {

x-pack/plugins/fleet/public/applications/fleet/mock/plugin_configuration.ts

@@ -15,7 +15,7 @@ export const createConfigurationMock = (): FleetConfigType => {
     agents: {
       enabled: true,
       elasticsearch: {
-        host: '',
+        hosts: [''],
         ca_sha256: '',
       },
     },

x-pack/plugins/fleet/server/index.ts

@@ -41,6 +41,23 @@ export const config: PluginConfigDescriptor = {
     unused('agents.pollingRequestTimeout'),
     unused('agents.tlsCheckDisabled'),
     unused('agents.fleetServerEnabled'),
+    (fullConfig, fromPath, addDeprecation) => {
+      const oldValue = fullConfig?.xpack?.fleet?.agents?.elasticsearch?.host;
+      if (oldValue) {
+        delete fullConfig.xpack.fleet.agents.elasticsearch.host;
+        fullConfig.xpack.fleet.agents.elasticsearch.hosts = [oldValue];
+        addDeprecation({
+          message: `Config key [xpack.fleet.agents.elasticsearch.host] is deprecated and replaced by [xpack.fleet.agents.elasticsearch.hosts]`,
+          correctiveActions: {
+            manualSteps: [
+              `Use [xpack.fleet.agents.elasticsearch.hosts] with an array of host instead.`,
+            ],
+          },
+        });
+      }
+
+      return fullConfig;
+    },
   ],
   schema: schema.object({
     enabled: schema.boolean({ defaultValue: true }),
@@ -49,7 +66,7 @@ export const config: PluginConfigDescriptor = {
     agents: schema.object({
       enabled: schema.boolean({ defaultValue: true }),
       elasticsearch: schema.object({
-        host: schema.maybe(schema.string()),
+        hosts: schema.maybe(schema.arrayOf(schema.uri({ scheme: ['http', 'https'] }))),
         ca_sha256: schema.maybe(schema.string()),
       }),
       fleet_server: schema.maybe(

x-pack/plugins/fleet/server/services/output.test.ts

@@ -0,0 +1,85 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { outputService } from './output';
+
+import { appContextService } from './app_context';
+
+jest.mock('./app_context');
+
+const mockedAppContextService = appContextService as jest.Mocked<typeof appContextService>;
+
+const CLOUD_ID =
+  'dXMtZWFzdC0xLmF3cy5mb3VuZC5pbyRjZWM2ZjI2MWE3NGJmMjRjZTMzYmI4ODExYjg0Mjk0ZiRjNmMyY2E2ZDA0MjI0OWFmMGNjN2Q3YTllOTYyNTc0Mw==';
+
+const CONFIG_WITH_ES_HOSTS = {
+  enabled: true,
+  agents: {
+    enabled: true,
+    elasticsearch: {
+      hosts: ['http://host1.com'],
+    },
+  },
+};
+
+const CONFIG_WITHOUT_ES_HOSTS = {
+  enabled: true,
+  agents: {
+    enabled: true,
+    elasticsearch: {},
+  },
+};
+
+describe('Output Service', () => {
+  describe('getDefaultESHosts', () => {
+    afterEach(() => {
+      mockedAppContextService.getConfig.mockReset();
+      mockedAppContextService.getConfig.mockReset();
+    });
+    it('Should use cloud ID as the source of truth for ES hosts', () => {
+      // @ts-expect-error
+      mockedAppContextService.getCloud.mockReturnValue({
+        isCloudEnabled: true,
+        cloudId: CLOUD_ID,
+      });
+
+      mockedAppContextService.getConfig.mockReturnValue(CONFIG_WITH_ES_HOSTS);
+
+      const hosts = outputService.getDefaultESHosts();
+
+      expect(hosts).toEqual([
+        'https://cec6f261a74bf24ce33bb8811b84294f.us-east-1.aws.found.io:443',
+      ]);
+    });
+
+    it('Should use the value from the config if not in cloud', () => {
+      // @ts-expect-error
+      mockedAppContextService.getCloud.mockReturnValue({
+        isCloudEnabled: false,
+      });
+
+      mockedAppContextService.getConfig.mockReturnValue(CONFIG_WITH_ES_HOSTS);
+
+      const hosts = outputService.getDefaultESHosts();
+
+      expect(hosts).toEqual(['http://host1.com']);
+    });
+
+    it('Should use the default value if there is no config', () => {
+      // @ts-expect-error
+      mockedAppContextService.getCloud.mockReturnValue({
+        isCloudEnabled: false,
+      });
+
+      mockedAppContextService.getConfig.mockReturnValue(CONFIG_WITHOUT_ES_HOSTS);
+
+      const hosts = outputService.getDefaultESHosts();
+
+      expect(hosts).toEqual(['http://localhost:9200']);
+    });
+  });
+});

x-pack/plugins/fleet/server/services/output.ts

@@ -16,6 +16,8 @@ import { normalizeHostsForAgents } from './hosts_utils';
 
 const SAVED_OBJECT_TYPE = OUTPUT_SAVED_OBJECT_TYPE;
 
+const DEFAULT_ES_HOSTS = ['http://localhost:9200'];
+
 class OutputService {
   public async getDefaultOutput(soClient: SavedObjectsClientContract) {
     return await soClient.find<OutputSOAttributes>({
@@ -27,17 +29,11 @@ class OutputService {
 
   public async ensureDefaultOutput(soClient: SavedObjectsClientContract) {
     const outputs = await this.getDefaultOutput(soClient);
-    const cloud = appContextService.getCloud();
-    const cloudId = cloud?.isCloudEnabled && cloud.cloudId;
-    const cloudUrl = cloudId && decodeCloudId(cloudId)?.elasticsearchUrl;
-    const flagsUrl = appContextService.getConfig()!.agents.elasticsearch.host;
-    const defaultUrl = 'http://localhost:9200';
-    const defaultOutputUrl = cloudUrl || flagsUrl || defaultUrl;
 
     if (!outputs.saved_objects.length) {
       const newDefaultOutput = {
         ...DEFAULT_OUTPUT,
-        hosts: [defaultOutputUrl],
+        hosts: this.getDefaultESHosts(),
         ca_sha256: appContextService.getConfig()!.agents.elasticsearch.ca_sha256,
       } as NewOutput;
 
@@ -50,6 +46,20 @@ class OutputService {
     };
   }
 
+  public getDefaultESHosts(): string[] {
+    const cloud = appContextService.getCloud();
+    const cloudId = cloud?.isCloudEnabled && cloud.cloudId;
+    const cloudUrl = cloudId && decodeCloudId(cloudId)?.elasticsearchUrl;
+    const cloudHosts = cloudUrl ? [cloudUrl] : undefined;
+    const flagHosts =
+      appContextService.getConfig()!.agents?.elasticsearch?.hosts &&
+      appContextService.getConfig()!.agents.elasticsearch.hosts?.length
+        ? appContextService.getConfig()!.agents.elasticsearch.hosts
+        : undefined;
+
+    return cloudHosts || flagHosts || DEFAULT_ES_HOSTS;
+  }
+
   public async getDefaultOutputId(soClient: SavedObjectsClientContract) {
     const outputs = await this.getDefaultOutput(soClient);