After installing and successfully starting nagios server you may encounter a warning:

Starting nagios: No directory, logging in with HOME=

This is reported because install script or you didn’t create a /home directory for user nagios.

To solve this simply follow these steps:

Create a /home/nagios directory and change permissions (all executed as sudo):

mkdir/home/nagios 
chown-R nagios:nagios/home/nagios

Then set new home directory for user nagios:

usermod --home /home/nagios nagios

Finally restart nagios service:

service nagios restart

That’s it, no more logging in to /Home Warning :)