Why hdfs namenode and datanode both always listen on 0.0.0.0 at a random port?

Question

I installed a new hadoop-2.2.0 today, I found after hdfs is started (using /sbin/start-dfs.sh), namenode and datanode both always listen on 0.0.0.0 at a random port? I cannot find relate configuration on http://hadoop.apache.org/docs/r2.3.0/hadoop-project-dist/hadoop-hdfs/hdfs-default.xml.

The port is not 50070, 50470, 50090, 50010, 50020, 50075, 50475...etc. which are listed on hdfs-default.xml, it is just a random port.

8369 Jps
8109 DataNode
7936 NameNode

Namenode listens on the followings:

tcp 0 0 0.0.0.0:46628 0.0.0.0:* LISTEN 7936/java        <==
tcp 0 0 10.173.130.119:9000 0.0.0.0:* LISTEN 7936/java
tcp 0 0 10.173.130.119:50070 0.0.0.0:* LISTEN 7936/java

Datanode listens on the followings:

tcp 0 0 10.173.130.119:50020 0.0.0.0:* LISTEN 8109/java
tcp 0 0 0.0.0.0:35114 0.0.0.0:* LISTEN 8109/java        <==
tcp 0 0 10.173.130.119:50010 0.0.0.0:* LISTEN 8109/java
tcp 0 0 10.173.130.119:50075 0.0.0.0:* LISTEN 8109/java

Thanks for any advise.

Does anyone know how to change this listener of 0.0.0.0:random_port? Thanks a lot! — user2093994

sathish reddy sathish reddy · Accepted Answer · 2014-05-30T10:22:32

Yes It assigns random port everytime a namenode or datanode restarted. But if you observer all the namenode listeners running on same process id in this case (7936) and Datanode listeners run on same process id ie 8109. So internally process is same.

Why hdfs namenode and datanode both always listen on 0.0.0.0 at a random port?

1 Answers