How to solve message "Starting nagios:No directory, logging in with HOME=/" when starting nagios deamon

I wrote a script of installing nagios 3 named "install-nagios3.sh" on my github repository (https://github.com/yeonki-choi/nagios) and tested it. After ran this, everything was fine excepts for message "Starting nagios:No directory, logging in with HOME=/" when starting nagios daemon.

$ sudo service nagios start
Starting nagios:No directory, logging in with HOME=/
done.

I found this message was same-produced when I switched to user "nagios". It was caused there was no home directory for user "nagios". This script created the user "nagios" with no home directory during running to own nagios-core's home directory and start its daemon.

$ sudo su - nagios
No directory, logging in with HOME=/

To do solve this, it just make home directory for that user

# Make a directory and changed the ownership
$ sudo mkdir /home/nagios
$ sudo chown -R nagios:nagios /home/nagios

# Setting the directory as the home of nagios
$ sudo usermod --home /home/nagios nagios
usermod: no changes

# Restarting nagios daemon, this time there is no above message 
$ sudo service nagios restart
Running configuration check...done.
Stopping nagios: done.
Starting nagios: done.