Most of the when we start to setup any kind of cluster (for Hadoop, Spark etc…) from scratch, we as a beginner often face certain problems while performing steps (like setup Static IP address or setup FQDN) after installation of Linux flavour OS on our VM or Machine. There are very less forums where you can get all of these bazics steps together along with full understanding. Here I have tried to explain you the process of setting up static IP address and FQDN (Fully Qualified Domain Name) in 5 steps. All of these steps are tested on VM/Machine available straight after minimal installation of CentOS 6.4.
Setting up keyless SSH is quite easy on CentOS but still sometimes there are chances that after following all the steps mentioned in How to setup Keyless SSH with non root users in CentOS post it is still not setup properly. There could be many possibilities as a root cause like improper permissions, invalid configuration etc. I have mentioned mainly four debug points which you should follow if your keyless ssh setup seems to be misbehaving.