unable to check nodes on hadoop [Connection refused]

Question

If I type http://localhost:50070 or http://localhost:9000 to see the nodes,my browser shows me nothing I think it can't connect to the server. I tested my hadoop with this command:

hadoop jar hadoop-*test*.jar TestDFSIO -write -nrFiles 10 -fileSize 1000

but too didn't work and it tries to connect to the server,this is the output:

12/06/06 17:25:24 INFO mapred.FileInputFormat: nrFiles = 10
12/06/06 17:25:24 INFO mapred.FileInputFormat: fileSize (MB) = 1000
12/06/06 17:25:24 INFO mapred.FileInputFormat: bufferSize = 1000000
12/06/06 17:25:25 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 0 time(s).
12/06/06 17:25:26 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 1 time(s).
12/06/06 17:25:27 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 2 time(s).
12/06/06 17:25:28 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 3 time(s).
12/06/06 17:25:29 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 4 time(s).
12/06/06 17:25:30 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 5 time(s).
12/06/06 17:25:31 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 6 time(s).
12/06/06 17:25:32 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 7 time(s).
12/06/06 17:25:33 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 8 time(s).
12/06/06 17:25:34 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9000. Already tried 9 time(s).
java.net.ConnectException: Call to localhost/127.0.0.1:9000 failed on connection exception: java.net.ConnectException: Connection refused

I changed some files like this: in conf/core-site.xml:

<configuration>
  <property>
    <name>fs.default.name</name>
    <value>hdfs://localhost:9000</value>
  </property>

in conf/hdfs-site.xml:

<configuration>
  <property>
    <name>dfs.replication</name>
    <value>1</value>
  </property>
</configuration>
</configuration>

in conf/mapred-site.xml:

<configuration>
  <property>
    <name>mapred.job.tracker</name>
    <value>localhost:9001</value>
  </property>
</configuration>

Thanks for your attention. If I run this command:

cat /etc/hosts

I see:

127.0.0.1   localhost
127.0.1.1   ubuntu.ubuntu-domain    ubuntu

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

and if i run this one:

ps axww | grep hadoop

I see this result:

2170 pts/0    S+     0:00 grep --color=auto hadoop

but no effect. Have you any idea, how can I solve my problem?

Answer 1

There are few things that you need to take care of before starting hadoop services.

Check what this returns:

hostname --fqdn 

In your case this should be localhost. Also comment out IPV6 in /etc/hosts.

Did you format the namenode before starting HDFS.

hadoop namenode -format

How did you install Hadoop. Location of log files will depend on that. Usually it is in location "/var/log/hadoop/" if you have used cloudera's distribution.

If you are a complete newbie, I suggest installing Hadoop using Cloudera SCM which is quite easy. I have posted my approach in installing Hadoop with Cloudera's distribution.

Also

Make sure DFS location has a write permission. It usually sits @ /usr/local/hadoop_store/hdfs

That is a common reason.