HADOOP-11328. ZKFailoverController does not log Exception when doRun raises errors. Contributed by Tianyin Xu.

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -525,6 +525,9 @@ Release 2.8.0 - UNRELEASED
     HADOOP-11357. Print information of the build enviornment in test-patch.sh
     (aw)
 
+    HADOOP-11328. ZKFailoverController does not log Exception when doRun raises
+    errors. (Tianyin Xu via ozawa)
+
   OPTIMIZATIONS
 
     HADOOP-11785. Reduce the number of listStatus operation in distcp

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

@@ -180,6 +180,7 @@ public Integer run() {
         }
       });
     } catch (RuntimeException rte) {
+      LOG.fatal("The failover controller encounters runtime error: " + rte);
       throw (Exception)rte.getCause();
     }
   }