Docker sandbox-hdp.hortonworks.com:50070: Connection refused (Connection refused

[#1]

Hello,

Just trying to work through the tutorial, im using the docker version. All was going well, until I got to the "explore Ambari" part. It seems some connections are getting refused, yet Ambari is running fine, and I can access the sandbox through the terminal and stop/start Ambari. Please have a look at the picture below.

[#2]

@Tim Roberts

Looks like in your case the HDFS Service check is failing because the HDFS service might not be healthy.

So please check the ambari UI --> HDFS --> "Service Actions" and then restart the HDFS services again then validate if the port 50070 is opened successfully or not?

# netstat -tnlpa | grep 50070
(OR)
# netstat -tnlpa | grep 	`cat /var/run/hadoop/hdfs/hadoop-hdfs-namenode.pid`

.

[#3]

Hey Jay, thanks for the reply 🙂

Am I doing this correctly?

[#4]

@Tim Roberts

Your netstat command output shows that your NameNode is not running because we do not see 50070 port listening at all.

So please login to ambari UI and then Navigate to

HDFS --> "Service Actions" (Drop Down) --> "Restart All"

.

Then check the NameNode logs to see if there are any strange errors. And then again validate the port 50070 is opened or not?

Once you see that port 50070 is listening fine then you can try accessing the Hive View..

[#5]

@Jay Kumar SenSharma

Thanks yes I did the restart all, and the result checking if 50070 was open as shown in the picture. Are you able to tell me how to check the namenode logs?

[#6]

@Tim Roberts

If the port 50070 is opened by the NameNode then we should see output like following:

[root@sandbox ~]# netstat -tnlpa | grep 50070
tcp        0      0 172.17.0.2:50070            0.0.0.0:*                   LISTEN      512/java 


[root@sandbox ~]# netstat -tnlpa | grep `cat /var/run/hadoop/hdfs/hadoop-hdfs-namenode.pid`
tcp        0      0 172.17.0.2:8020             0.0.0.0:*                   LISTEN      512/java            
tcp        0      0 172.17.0.2:50070            0.0.0.0:*                   LISTEN      512/java            
tcp        0      0 172.17.0.2:8020             172.17.0.2:36554            ESTABLISHED 512/java            
tcp        0      0 172.17.0.2:36554            172.17.0.2:8020             ESTABLISHED 512/java            
tcp        0      0 172.17.0.2:36512            172.17.0.2:8020             TIME_WAIT   -                   
tcp        0      0 172.17.0.2:8020             172.17.0.2:40692            ESTABLISHED 512/java            
tcp        0      0 172.17.0.2:35336            172.17.0.2:50010            ESTABLISHED 512/java            
tcp        0      0 172.17.0.2:8020             172.17.0.2:36576            ESTABLISHED 512/java            
tcp        0      0 172.17.0.2:8020             172.17.0.2:36590            ESTABLISHED 512/java            
tcp        0      0 172.17.0.2:8020             172.17.0.2:40554            ESTABLISHED 512/java  

.

For Name Node log (to see if there are any errors during startup) we can refer to the following log:

# less /var/log/hadoop/hdfs/hadoop-hdfs-namenode-sandbox.hortonworks.com.log 

.

[#7]

@Jay Kumar SenSharma Cool thanks- I can see the log, and there is indeed an error:

[#8]

@Tim Roberts

Can you please check if you have mistakenly modified your "/etc/hosts' file by any chance?

Following works for me.

[root@sandbox ~]# cat /etc/hosts
127.0.0.1    localhost
::1    localhost ip6-localhost ip6-loopback
fe00::0    ip6-localnet
ff00::0    ip6-mcastprefix
ff02::1    ip6-allnodes
ff02::2    ip6-allrouters
172.17.0.2    sandbox.hortonworks.com sandbox<br>

.

FQDN of your Sandbox should be correctly resolvable.

[root@sandbox ~]# hostname -f
sandbox.hortonworks.com

.

https://community.hortonworks.com/questions/148362/service-hdfs-check-failed-2.html

[#9]

localhost name resolution is handled within DNS itself. 
#127.0.0.1 localhost
#::1 localhost 
127.0.0.1 localhost sandbox.hortonworks.com sandbox-hdp.hortonworks.com sandbox-hdf.hortonworks.com

@Jay Kumar SenSharma Above is my etc/hosts

Should it be 172.17.0.2 instead?

[#10]

@Tim Roberts

Your /etc/hosts file does not look right. It is not the default one that comes with the HDP Sandbox.

So please check with any other HDP Sandbox image or use the default "/etc/hosts" file.

Try using my File data (Keep a backup of your File). Then after modifying the /etc/hosts file better to restart the whole Sandbox before testing further.

.