HDFS_NAMENODE_USER, HDFS_DATANODE_USER & HDFS_SECONDARYNAMENODE_USER not defined

Question

I am new to hadoop.
I\'m trying to install hadoop in my laptop in Pseudo-Distributed mode.
I am running it with root user, but I\'m getting the error below.

Answer 1

Based on on the first warning, HADOOP_PREFIX, sounds like you've not defined HADOOP_HOME correctly.

This would be done in your /etc/profile.d.

hadoop-env.sh is where the remainder of those variables are are defined.

Please refer to the UNIX Shell Guide

hadoop is not able to access ssh service with other user

This has nothing to do with Hadoop itself. It's basic SSH account management. You need to

1. Make the hadoop (and other, like yarn) accounts on all machines of a cluster (see adduser command documentation)
2. Copy a passwordless SSH key using ssh-copy-id hadoop@localhost, for example

If you don't need distributed mode and just want to use Hadoop locally, you can use a Mini Cluster.

The documentation also recommends making a single node installation before continuing to pseudo distributed