After testing a nagios configuration update ( including a new service or renaming some host etc..) before committing the changes and reloading / restarting the nagios service a good test is the following:
/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
A healthy config would result in something like the following
11:52:44-root@nagios:/usr/local/nagios/etc$ /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
Nagios Core 3.4.1
Copyright (c) 2009-2011 Nagios Core Development Team and Community Contributors
Copyright (c) 1999-2009 Ethan Galstad
Last Modified: 05-11-2012
License: GPL
Website: http://www.nagios.org
Reading configuration data…
Read main config file okay…
Processing object config file ‘/usr/local/nagios/etc/objects/commands.cfg’…
Processing object config file ‘/usr/local/nagios/etc/objects/contacts.cfg’…
Processing object config file ‘/usr/local/nagios/etc/objects/timeperiods.cfg’…
Processing object config file ‘/usr/local/nagios/etc/objects/templates.cfg’…
Processing object config file ‘/usr/local/nagios/etc/objects/localhost.cfg’…
Processing object config file ‘/usr/local/nagios/etc/objects/www.cfg’…
Read object config files okay…
Running pre-flight check on configuration data…
Checking services…
Checked 16 services.
Checking hosts…
Checked 2 hosts.
Checking host groups…
Checked 1 host groups.
Checking service groups…
Checked 0 service groups.
Checking contacts…
Checked 1 contacts.
Checking contact groups…
Checked 1 contact groups.
Checking service escalations…
Checked 0 service escalations.
Checking service dependencies…
Checked 0 service dependencies.
Checking host escalations…
Checked 0 host escalations.
Checking host dependencies…
Checked 0 host dependencies.
Checking commands…
Checked 24 commands.
Checking time periods…
Checked 5 time periods.
Checking for circular paths between hosts…
Checking for circular host and service dependencies…
Checking global event handlers…
Checking obsessive compulsive processor commands…
Checking misc settings…
Total Warnings: 0
Total Errors: 0
Things look okay – No serious problems were detected during the pre-flight check
12:05:08-root@nagios:/usr/local/nagios/etc$
Errors would result in something like this
12:13:14-root@nagios:/usr/local/nagios/etc$ /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
Nagios Core 3.4.1
Copyright (c) 2009-2011 Nagios Core Development Team and Community Contributors
Copyright (c) 1999-2009 Ethan Galstad
Last Modified: 05-11-2012
License: GPL
Website: http://www.nagios.org
Reading configuration data…
Read main config file okay…
Processing object config file ‘/usr/local/nagios/etc/objects/commands.cfg’…
Processing object config file ‘/usr/local/nagios/etc/objects/contacts.cfg’…
Processing object config file ‘/usr/local/nagios/etc/objects/timeperiods.cfg’…
Processing object config file ‘/usr/local/nagios/etc/objects/templates.cfg’…
Processing object config file ‘/usr/local/nagios/etc/objects/localhost.cfg’…
Processing object config file ‘/usr/local/nagios/etc/objects/www.cfg’…
Error: Invalid service object directive ‘servicedescription’.
Error: Could not add object property in file ‘/usr/local/nagios/etc/objects/www.cfg’ on line 132.
Error processing object config files!
***> One or more problems was encountered while processing the config files…
Check your configuration file(s) to ensure that they contain valid
directives and data defintions. If you are upgrading from a previous
version of Nagios, you should be aware that some variables/definitions
may have been removed or modified in this version. Make sure to read
the HTML documentation regarding the config files, as well as the
‘Whats New’ section to find out what has changed.
12:13:16-root@nagios:/usr/local/nagios/etc$