add links

Author: liyanp1987

articles/hdinsight/spark/TOC.yml

@@ -319,6 +319,8 @@
       items:
       - name: Debug Spark jobs
         href: apache-spark-job-debugging.md
+      - name: Debug Spark Jobs through Job Graph
+        href: apache-azure-spark-history-server.md
       - name: Use IntelliJ to debug Spark job
         href: apache-spark-intellij-tool-debug-remotely-through-ssh.md
       - name: Troubleshoot a slow or failing HDInsight cluster

articles/hdinsight/spark/apache-spark-job-debugging.md

@@ -103,6 +103,7 @@ Once a job is completed, the information about the job is persisted in the Spark
 
 ## See also
 *  [Manage resources for the Apache Spark cluster in Azure HDInsight](apache-spark-resource-manager.md)
+*  [Debug Spark Jobs using extended Spark History Server](apache-azure-spark-history-server.md)
 
 ### For data analysts