Support Questions
Find answers, ask questions, and share your expertise

Connection refused error while starting namenode from Ambari UI

I am getting error while installing namenode where it says "-safemode get | grep 'Safe mode is OFF''"

Ambari:2.7.0.0

HDP:3.0

I got the below error and I ran :

>hdfs dfsadmin -safemode leave
>Output:safemode: Call From devaz01/10.161.137.4 to devaz01:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused

then I ran>chmod -R 644 /var/log/hadoop/hdfs
Since then I am getting: Execution of 'ambari-sudo.sh su hdfs -l -s /bin/bash -c 'ulimit -c unlimited ;  /usr/hdp/3.0.1.0-187/hadoop/bin/hdfs --config /usr/hdp/3.0.1.0-187/hadoop/conf --daemon start namenode'' returned 1. ERROR: Unable to write in /var/log/hadoop/hdfs. Aborting.

019-02-08 03:31:21,394 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://machine:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. safemode: Call From machine/xx.xxx.xxx.x to machine:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused
safemode: Call From machine/10.161.137.4 to machine:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused 
1 ACCEPTED SOLUTION

Super Mentor

@Shraddha Singh

As we see the error :

ERROR: Unable to write in /var/log/hadoop/hdfs. Aborting.

.

So please make sure that the dir permissions are correctly set as following:

# ls -ld /var/log/hadoop/hdfs
drwxr-xr-x. 2 hdfs hadoop 8192 Feb 11 03:27 /var/log/hadoop/hdfs

.

If you see permissions are incorrectly set then please do the following and then try starting process again: (You executed chmod, better you change the ownership of the mentioned directories as following)

# chown -R hdfs:hadoop /var/log/hadoop

.

Then try your commands:

# su - hdfs
# hdfs dfsadmin -safemode leave

.

View solution in original post

5 REPLIES 5

Mentor

@Shraddha Singh

You are trying to run the dfsadmin command when the Namenode is not yet started. Please ensure the namendoe is in started status in Ambari

Hi @Geoffrey Shelton Okot

I am getting the above error while starting the namenode from Ambari UI . When I click 'Start All' the services does not start because namenode is not getting started due to the above error.

Super Mentor

@Shraddha Singh

As we see the error :

ERROR: Unable to write in /var/log/hadoop/hdfs. Aborting.

.

So please make sure that the dir permissions are correctly set as following:

# ls -ld /var/log/hadoop/hdfs
drwxr-xr-x. 2 hdfs hadoop 8192 Feb 11 03:27 /var/log/hadoop/hdfs

.

If you see permissions are incorrectly set then please do the following and then try starting process again: (You executed chmod, better you change the ownership of the mentioned directories as following)

# chown -R hdfs:hadoop /var/log/hadoop

.

Then try your commands:

# su - hdfs
# hdfs dfsadmin -safemode leave

.

Thanks @Jay Kumar SenSharma

That worked for me!

Mentor

@Shraddha Singh

Any updates did my response resolve the issue if so accept so the thread is marked as closed.

; ;