# Hadoop Preparation

We need to add a new host name in /etc/hosts, called hadoop.master.lan, in my case:

cat /etc/hosts

…

10.0.0.46 master.hadoop.lan

You need to specify your IP address, not copy 10.0.0.46 in this slide. Run “ifconfig” to find out the IP address of your host.

Now, configure ssh key based authentication for hadoop account by running the below commands (replace the hostname or FQDN against the ssh-copy-id command accordingly).

Also, leave the passphrase filed blank in order to automatically login via ssh.

$ ssh-keygen -t rsa

$ ssh-copy-id master.hadoop.lan

You will see something similar to below:

![](/files/-M1dafAIH3pcOewihpR0)

You can test

ssh master.hadoop.lan

You should be able to log in by ssh without password


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