HADOOP-10668. TestZKFailoverControllerStress#testExpireBackAndForth occasionally fails. Contributed by Ming Ma.

(cherry picked from commit 7fc1f2f5cf4312d72aeffb1a9cef497d00c60adb)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ha/ZKFailoverController.java

@@ -153,7 +153,9 @@ public abstract class ZKFailoverController {
   public HAServiceTarget getLocalTarget() {
     return localTarget;
   }
-  
+
+  HAServiceState getServiceState() { return serviceState; }
+
   public int run(final String[] args) throws Exception {
     if (!localTarget.isAutoFailoverEnabled()) {
       LOG.fatal("Automatic failover is not enabled for " + localTarget + "." +

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/ha/MiniZKFCCluster.java

@@ -163,8 +163,8 @@ public class MiniZKFCCluster {
    */
   public void waitForHAState(int idx, HAServiceState state)
       throws Exception {
-    DummyHAService svc = getService(idx);
-    while (svc.state != state) {
+    DummyZKFC svc = getZkfc(idx);
+    while (svc.getServiceState() != state) {
       ctx.checkException();
       Thread.sleep(50);
     }