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NameNode is not starting in Ambari

NameNode is not starting in Ambari

New Contributor

Hi,

I am facing problem while creating HDP cluster through Ambari.

I am having 3 zookeeper servers and those are in aws environment. While trying to start all the services I am getting the following error in hbase-master -> namenode log. Please help.

2016-06-29 07:26:46,200 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://hdphost.hmaster.com:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. safemode: Call From hdphost.hmaster.com/54.252.82.136 to hdphost.hmaster.com:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused
5 REPLIES 5

Re: NameNode is not starting in Ambari

Rising Star

@Payel Datta please try to manually execute the command that ambari is trying, the one where it is checking on safemode. You will also want to check if the daemon is running and namenode log is being generated on hdphost.hmaster.com

Re: NameNode is not starting in Ambari

Expert Contributor

@Payel Datta

This issue usually happens when either datanodes are not running or they are unable to communicate with Namenode. Please make sure all the required HDFS ports are open to communicate within the cluster in your AWS security group. Here is a list of ports which need to be opened:

https://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.4.0/bk_HDP_Reference_Guide/content/hdfs-ports.h...

Re: NameNode is not starting in Ambari

Rising Star

@Payel Datta

I see that the issue is due to connection failure :

call From hdphost.hmaster.com/54.252.82.136 to hdphost.hmaster.com:8020 failed on connection exception: java.net.ConnectException: Connection refused

1. Is the Name resolution set correctly? For AWS, this is sometimes a problem.

2. Is the routing proper?

The issue is mostly network connection due to name resilution.

Re: NameNode is not starting in Ambari

New Contributor

I have checked with /etc/hosts for each node. They are same.

Re: NameNode is not starting in Ambari

Expert Contributor

@Payel Datta

Did you use external hostnames or internal ones during the installation? Internal hostname is recommended and external names do not work

.