Meaning of fs defaultFS property in core-site xml in hadoop

Question

I am installing Hadoop distributed mode cluster, and I have downloaded Hadoop and extracted the compressed file. While editing the configuration file, I am having some doubts. What does the fs.defaultFS property does in core-site.xml file.

I have 3 nodes:

192.168.101.1 --> Master Machine (NameNode, SecondaryNameNode & ResourceManager daemons)

192.168.101.2 --> Slave1 (Datanode & NodeManager daemons)

192.168.103.3 --> Slave2 (Datanode & NodeManager daemons)

My configuration is as below:

<property>
   <name>fs.default.name</name>
   <value>hdfs://192.168.1.2:9000/</value>
</property>

Do we have to pass the address of the NameNode here?

Answer 1

fs.default.name property in core-site.xml tells the address of the NameNode and all the HDFS command refers to the this NameNode address. It tells the default HDFS address.

9000 is the port where the datanode will send heartbeat to namenode.

Answer 2

It allows to run dfs commands more easily. Otherwise we have to give the full site name.

For Example

To remove file from hdfs, we use $ hdfs dfs -rm instead of $ hdfs dfs -rm hdfs://hdfs/.

Thank you