From eb488705eedeea16254e059f26e5528f58d936f1 Mon Sep 17 00:00:00 2001
From: Vinayakumar B <vinayakumarb@google.com>
Date: Tue, 12 Aug 2025 05:32:14 +0000
Subject: [PATCH] YARN-11839. [RM HA] - In corner case, RM stay in ACTIVE with
 RMStateStore in FENCED state

---
 .../hadoop/yarn/server/resourcemanager/ResourceManager.java | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ResourceManager.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ResourceManager.java
index b35f8cb295cae..b2d5a9c9d394d 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ResourceManager.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ResourceManager.java
@@ -1218,7 +1218,11 @@ protected void serviceStop() throws Exception {
    * Transition to standby state in a new thread. The transition operation is
    * asynchronous to avoid deadlock caused by cyclic dependency.
    */
-  private void handleTransitionToStandByInNewThread() {
+  private synchronized void handleTransitionToStandByInNewThread() {
+    if (rmContext.getHAServiceState() == HAServiceProtocol.HAServiceState.STANDBY) {
+      LOG.info("RM already in standby state");
+      return;
+    }
     Thread standByTransitionThread =
         new Thread(activeServices.standByTransitionRunnable);
     standByTransitionThread.setName("StandByTransitionThread");