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Resolving Permission Issue in Multi-node Hadoop Cluster

Sometimes it has been observed that when we configure and deploy multi-node Hadoop cluster or add new DataNodes, there is an SSH permission issue in communication with Hadoop daemons.

This short article aims to explain how we can resolve the permission issue among DataNodes with NameNode while trying to establish the Secure Shell/SSH without a passphrase. By using DataNode Protocol, all DataNodes talk to the NameNode. By design, the NameNode never initiates any RPCs (Remote Procedure Call). Instead, it only responds to RPC requests issued by DataNodes or clients.

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An Introduction to SSH – Secure Shell

What Is SSH?

SSH is a network protocol that allows a secure connection between different computers. SSH protocol also referred to as Secure Shell, provides many functionalities like,

  • Strong connection and security
  • Strong authentication
  • Maintains connection integrity
  • Strong encryption.

In general, there are different ways of logging in to a remote machine,