HDFS-7329. Improve logging when MiniDFSCluster fails to start. Contributed by Byron Wong.

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -89,6 +89,9 @@ Release 2.7.0 - UNRELEASED
     HDFS-7361. TestCheckpoint fails after change of log message related to
     locking violation. (shv)
 
+    HDFS-7329. Improve logging when MiniDFSCluster fails to start.
+    (Byron Wong via shv)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/MiniDFSCluster.java

@@ -810,7 +810,7 @@ public class MiniDFSCluster {
             format, startOpt, clusterId, conf);
       } catch (IOException ioe) {
         LOG.error("IOE creating namenodes. Permissions dump:\n" +
-            createPermissionsDiagnosisString(data_dir));
+            createPermissionsDiagnosisString(data_dir), ioe);
         throw ioe;
       }
       if (format) {