Support Questions

Find answers, ask questions, and share your expertise
Announcements
Celebrating as our community reaches 100,000 members! Thank you!

Unable to start the HDFS using Ambari

avatar
Contributor

Hi All ,

I am trying to start the HDFS using ambari . It remains stuck at following error .

safemode: Call From  hostname/16.250.53.40 to hostname:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused
2017-09-04 09:00:04,064 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://hostname:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. safemode:

 Call From hostname/16.250.53.40 to hostname:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused
safemode: 

Call From hostname/16.250.53.40 to hostname:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused
1 ACCEPTED SOLUTION

avatar
Master Mentor

@Kishore Kumar

Pleas emake sure that all the cluster nodes has correct FQDN configured. All the hosts are returning the correct FQDN (hostname) when we run the following command:

# hostname -f

.

Try starting the NameNode manually to see if it works ? As mentioned here: https://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.6.2/bk_administration/content/starting_hdp_serv...

.

View solution in original post

6 REPLIES 6

avatar
Master Mentor

@Kishore Kumar

Can you do the following as user root

# su - hdfs

Now as user hdfs

$ hdfs dfsadmin -safemode leave

Then restart through Ambari

avatar
Contributor

@Geoffrey Shelton Okot

I tried that several time . It give following error too

afemode: Call From hostname/16.250.53.40 to hostnamet:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see: http://wiki.apache.org/hadoop/ConnectionRefused

avatar
Master Mentor

@Kishore Kumar

Pleas emake sure that all the cluster nodes has correct FQDN configured. All the hosts are returning the correct FQDN (hostname) when we run the following command:

# hostname -f

.

Try starting the NameNode manually to see if it works ? As mentioned here: https://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.6.2/bk_administration/content/starting_hdp_serv...

.

avatar
Contributor

It works, after stating manually as mention on this doc .

Thanks

avatar
Expert Contributor
@Kishore Kumar

Did you check the connectivity from Ambari Server to Namenode service?

avatar
Master Mentor

@Kishore Kumar

Can you check the /etc/hosts on the cluster nodes and make sure the entries are like

IP:FQDN : short-name optional

And the FQDN on each host should be the exact output of

# hostname -f