List the namenode and datanodes of a cluster from any node?

hadoop mapreduce
T. Webster picture T. Webster · Jun 1, 2013 · Viewed 65.9k times · Source

From any node in a Hadoop cluster, what is the command to

  • identify the running namenode?
  • identify all running datanodes?

I have looked through the commands manual and have not found this.

Answer

Tejas Patil picture Tejas Patil · Jun 1, 2013

Use the dfsadmin command:

bin/hadoop dfsadmin -report

Update (2015):

bin/hdfs dfsadmin -report

Related questions

What is Hive: Return Code 2 from org.apache.hadoop.hive.ql.exec.MapRedTask

I am getting: FAILED: Execution Error, return code 2 from org.apache.hadoop.hive.ql.exec.MapRedTask While trying to make a copy of a partitioned table using the commands in the hive console: CREATE TABLE copy_table_name LIKE table_…

Read More
Setting the number of map tasks and reduce tasks

I am currently running a job I fixed the number of map task to 20 but and getting a higher number. I also set the reduce task to zero but I am still getting a number other than zero. The total …

Read More
Container is running beyond memory limits

In Hadoop v1, I have assigned each 7 mapper and reducer slot with size of 1GB, my mappers & reducers runs fine. My machine has 8G memory, 8 processor. Now with YARN, when run the same application on the same machine, I …

Read More