YARN-12002. Stop the Router delegation token secret manager on service stop

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/main/java/org/apache/hadoop/yarn/server/router/clientrm/RouterClientRMService.java

@@ -202,7 +202,18 @@ protected void serviceStop() throws Exception {
     if (this.server != null) {
       this.server.stop();
     }
-    userPipelineMap.clear();
+    // serviceStart() started the secret manager's ExpiredTokenRemover; stop it
+    // here, once the server accepts no more requests, so it does not outlive
+    // this service and keep using the federation state store. Server#stop does
+    // not wait for handlers already running, so one of those may still use the
+    // secret manager. Mirrors RMSecretManagerService#serviceStop.
+    if (this.routerDTSecretManager != null) {
+      this.routerDTSecretManager.stopThreads();
+    }
+    // serviceStart() creates the map, so it is null if the service never started.
+    if (userPipelineMap != null) {
+      userPipelineMap.clear();
+    }
     super.serviceStop();
   }
 

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/test/java/org/apache/hadoop/yarn/server/router/clientrm/TestRouterClientRMService.java

@@ -19,6 +19,7 @@
 package org.apache.hadoop.yarn.server.router.clientrm;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -29,6 +30,7 @@
 import java.util.Map;
 
 import org.apache.hadoop.security.UserGroupInformation;
+import org.apache.hadoop.service.Service.STATE;
 import org.apache.hadoop.yarn.api.protocolrecords.GetClusterMetricsResponse;
 import org.apache.hadoop.yarn.api.protocolrecords.GetClusterNodeLabelsResponse;
 import org.apache.hadoop.yarn.api.protocolrecords.GetClusterNodesResponse;
@@ -44,6 +46,7 @@
 import org.apache.hadoop.yarn.api.protocolrecords.SubmitApplicationResponse;
 import org.apache.hadoop.yarn.exceptions.YarnException;
 import org.apache.hadoop.yarn.server.router.clientrm.RouterClientRMService.RequestInterceptorChainWrapper;
+import org.apache.hadoop.yarn.server.router.security.RouterDelegationTokenSecretManager;
 import org.junit.jupiter.api.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -271,4 +274,33 @@ public ClientRequestInterceptor run() throws Exception {
     assertTrue(client1.interceptor == client2.interceptor);
   }
 
+  /**
+   * Stopping the service stops the delegation token secret manager's
+   * ExpiredTokenRemover thread, which serviceStart started.
+   */
+  @Test
+  public void testServiceStopStopsDelegationTokenSecretManager() {
+    MockRouterClientRMService service = getRouterClientRMService();
+    RouterDelegationTokenSecretManager dtSecretManager =
+        service.getRouterDTSecretManager();
+    assertTrue(dtSecretManager.isRunning());
+
+    service.stop();
+
+    assertFalse(dtSecretManager.isRunning());
+  }
+
+  /**
+   * A service that was initialized but never started can be stopped.
+   */
+  @Test
+  public void testServiceStopWithoutStart() {
+    MockRouterClientRMService service = new MockRouterClientRMService();
+    service.init(getConf());
+
+    service.stop();
+
+    assertEquals(STATE.STOPPED, service.getServiceState());
+  }
+
 }