Single machine installations:

Make sure entries exist in the /etc/hosts file for all IP addresses configured on the system, including 127.0.0.1.

Multiple machine installations:

Make sure entries exist in the /etc/hosts file for all IP addresses configured on the system, including 127.0.0.1, plus any other IP addresses in the cluster accessible from this machine. This is particularly important for NFS.

All machines:

Make sure each machine has set its permanent full hostname. Depending on the Linux distribution used, some alternatives you may follow are:

• By editing the /etc/hosts file, as mentioned above.
• By editing the /etc/hostname file.
• By running a command like "hostnamectl set-hostname enswitch.example.com".
• By running a command like "hostnamectl hostname enswitch.example.com".

Either way, when running the "hostname" or "hostname -f" commands you should get the effective machine hostname.