Nagios Support Forum

I'm running nagios core on CentOS 6.5, and I may have just crashed my Monitoring

I installed the nagvis following the guide in https://mathias-kettner.com/checkmk_livestatus.html

when done, I'm able to open the nagvis portal (localhost/nagvis) and add background and create maps.
but when I try to add a host, I'm getting the error "unable to fetch data from backend- failing back to input filed"

but I have now a bigger issue.
my nagios is not monitoring anymore, when I click on the Host ( in localhost/nagios) , I'm getting the error:

Whoops!

Error: Could not read host and service status information!

The most common cause of this error message (especially for new users), is the fact that Nagios is not actually running. If Nagios is indeed not running, this is a normal error message. It simply indicates that the CGIs could not obtain the current status of hosts and services that are being monitored. If you've just installed things, make sure you read the documentation on starting Nagios.

Some other things you should check in order to resolve this error include:

Check the Nagios log file for messages relating to startup or status data errors.
Always verify configuration options using the -v command-line option before starting or restarting Nagios!
Make sure you read the documentation on installing, configuring and running Nagios thoroughly before continuing. If all else fails, try sending a message to one of the mailing lists. More information can be found at http://www.nagios.org.


I went back to nagios and restarted the service and it's not restarting.

[root@ClearMon etc]# service nagios restart
Stopping nagios: [FAILED]
Starting nagios: [ OK ]
You have new mail in /var/spool/mail/root

I check the log and what I see is
[1411738873] Nagios 4.0.1 starting... (PID=8307)
[1411738873] Local time is Fri Sep 26 10:41:13 ADT 2014
[1411738873] LOG VERSION: 2.0
[1411738873] qh: Socket '/usr/local/nagios/var/rw/nagios.qh' successfully initialized
[1411738873] qh: core query handler registered
[1411738873] nerd: Channel hostchecks registered successfully
[1411738873] nerd: Channel servicechecks registered successfully
[1411738873] nerd: Channel opathchecks registered successfully
[1411738873] nerd: Fully initialized and ready to rock!
[1411738873] wproc: Successfully registered manager as @wproc with query handler
[1411738873] wproc: Registry request: name=Core Worker 8310;pid=8310
[1411738873] wproc: Registry request: name=Core Worker 8312;pid=8312
[1411738873] wproc: Registry request: name=Core Worker 8309;pid=8309
[1411738873] wproc: Registry request: name=Core Worker 8311;pid=8311
[1411738873] Error: Could not load module '/usr/local/lib/mk-livestatus/livestatus.o' -> /usr/local/lib/mk-livestatus/livestatus.o: undefined symbol: last_command_check
[1411738873] Error: Failed to load module '/usr/local/lib/mk-livestatus/livestatus.o'.
[1411738873] Error: Module loading failed. Aborting.


can some please help me on this, I may just crashed our production monitoring system.

It appears that A) you did not install nagvis, but mklivestatus and B) unfortunately followed the guide that does not work with core 4. I would suggest removing the livestatus broker module line from your nagios.cfg and restarting the core daemon. If you wanted livestatus and not nagvis, there is a core 4 branch floating around that should work fine.