YARN-9714. ZooKeeper connection in ZKRMStateStore leaks after RM transitioned to standby. Contributed by Tao Yang.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/recovery/ZKRMStateStore.java

@@ -443,7 +443,7 @@ public class ZKRMStateStore extends RMStateStore {
       verifyActiveStatusThread.join(1000);
     }
 
-    if (!HAUtil.isHAEnabled(getConfig())) {
+    if (resourceManager.getZKManager() == null) {
       CuratorFramework curatorFramework = zkManager.getCurator();
       IOUtils.closeStream(curatorFramework);
     }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/recovery/TestZKRMStateStore.java

@@ -450,6 +450,7 @@ public class TestZKRMStateStore extends RMStateStoreTestBase {
     rm = new MockRM(conf);
     rm.start();
     rm.getRMContext().getRMAdminService().transitionToActive(req);
+    stateStore = (ZKRMStateStore) rm.getRMContext().getStateStore();
     acls = stateStore.getACL(rootPath);
     assertEquals(acls.size(), 1);
     verifyZKACL("world", "anyone", Perms.ALL, acls);
@@ -460,6 +461,7 @@ public class TestZKRMStateStore extends RMStateStoreTestBase {
     rm = new MockRM(conf);
     rm.start();
     rm.getRMContext().getRMAdminService().transitionToActive(req);
+    stateStore = (ZKRMStateStore) rm.getRMContext().getStateStore();
     acls = stateStore.getACL(rootPath);
     assertEquals(acls.size(), 2);
     verifyZKACL("digest", "localhost", Perms.CREATE | Perms.DELETE, acls);