https://community.cloudera.com/t5/Support-Questions/Issue-quot-sandbox-hdp-hortonworks-com-8020-failed-on/m-p/235840#M197653 <P>Hi,</P> <P>&nbsp;</P> <P>In my CDA, on HDP while system is starting it is throwing below error:</P> <P>"sandbox-hdp.hortonworks.com:8020 failed on connection exception: java.net.connectexception: connection refused;" for namenode. Below is the more detailed log.</P> <P>Could you please let me know what should be done since it is not starting namenode and hence not letting to start entire system.</P> <PRE>stderr: stdout: 2019-07-20 01:20:47,602 - Waiting for this NameNode to leave Safemode due to the following conditions: HA: False, isActive: True, upgradeType: None 2019-07-20 01:20:47,604 - Waiting up to 19 minutes for the NameNode to leave Safemode... 2019-07-20 01:20:47,604 - Execute['/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://sandbox-hdp.hortonworks.com:8020 -safemode get | grep 'Safe mode is OFF''] {'logoutput': True, 'tries': 115, 'user': 'hdfs', 'try_sleep': 10} safemode: Call From <STRONG>sandbox-hdp.hortonworks.com/172.18.0.3 to sandbox-hdp.hortonworks.com:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see: &nbsp;http://wiki.apache.org/hadoop/ConnectionRefused</STRONG> 2019-07-20 01:20:51,904 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://sandbox-hdp.hortonworks.com:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. safemode: Call From sandbox-hdp.hortonworks.com/172.18.0.3 to sandbox-hdp.hortonworks.com:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see: <A href="http://wiki.apache.org/hadoop/ConnectionRefused" target="_blank" rel="noopener">http://wiki.apache.org/hadoop/ConnectionRefused</A> 2019-07-20 01:21:06,242 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://sandbox-hdp.hortonworks.com:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. 2019-07-20 01:21:19,389 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://sandbox-hdp.hortonworks.com:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. 2019-07-20 01:21:31,853 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://sandbox-hdp.hortonworks.com:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. 2019-07-20 01:21:45,871 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://sandbox-hdp.hortonworks.com:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. 2019-07-20 01:21:57,932 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://sandbox-hdp.hortonworks.com:8020 -safemode get | grep 'Safe mode is OFF'' returned 1.</PRE> Mon, 26 Aug 2019 01:35:25 GMT shashank_naresh 2019-08-26T01:35:25Z