In this section, we will look at the steps to install and enable a passwordless SSH. It's always better that you have a dedicated Linux user for Hadoop and HBase processes. Let's create a user for Hadoop and HBase and name it hbasehadoop. We will use this user to start and stop all Hadoop/HBase daemon processes. Once the user is created, we can generate SSH for the same and set up a passwordless SSH on all machines. This user must exist on all machines in the cluster. Also, this user must be provided a root access if we need to install SSH using this user, else we can create a simple user just to start and stop the process, and we can install using the existing root user. The following figure will give you a clear picture:

To add a user, the current user must be a root user. So, switch to the root user using the following command before setting up a password:

useraddhbasehadoop

To set a password for the hbasehadoop user, use the following command:

passwdhbasehadoop...