That typically means the check_nrpe plugin was unable to reach the NRPE server after a specified period (30 seconds by default). More info on NRPE in general: https://github.com/NagiosEnterprises/nrpe From the check_nrpe plugin's help menu: -t, --timeout=INTERVAL:STATE INTERVAL Number of seconds bef...

You could probably script something out using the external commands file and JSON CGIs: https://assets.nagios.com/downloads/nagioscore/docs/externalcmds/ https://labs.nagios.com/2014/06/19/exploring-the-new-json-cgis-in-nagios-core-4-0-7-part-1/ Else, there's a few related feature requests you may w...

The official documentation for installing on Ubuntu has a discrete step for configuring the service/daemon files: https://support.nagios.com/kb/article/nagios-core-installing-nagios-core-from-source-96.html#Ubuntu What process did you use to install Nagios Core? If you followed the official document...

the hosts can send out but nothing is allowed in. Passive checks were designed specifically for this use case. Practically every such network I've seen with federated Nagios Core installations has the single local Core instance shipping to a master Core instance via passive checks coupled to event ...

The way practically any Java runtime is monitored is via JMX , either remotely via JMX clients connecting to JMX servers or locally via some tool like jconsole . Here's the official documentation for monitoring Java runtimes via JMX with Nagios: https://assets.nagios.com/downloads/nagiosxi/docs/Moni...

What daemon is managing the service? Here are some service check examples: https://support.nagios.com/kb/article/service-checks-775.html If you're using init, you could probably peel the check_init_service script out from the linux-nrpe-agent tarball and load that up into your NRPE config. Let us kn...

In your command executed from the Nagios Core server: root@tgcs017:/usr/local/nagios/etc/objects/windowsservers# /usr/lib/nagios/plugins/check_nrpe -t 50 -H TGCS016 -c check_sqldbsize -a tgcs016\wsussql SUSDB 8000 5000 Have you taken Bash reserved characters into account? You may need a double backs...

Are you following any particular documentation for installing Nagios Core? Perhaps the official documentation for OSX? https://support.nagios.com/kb/article/nagios-core-installing-nagios-core-from-source-96.html#Apple_OS_X All that make step does is write some Apache configurations. If it's failing,...

Which version of Nagios Core are you using?

How many total checks is Nagios Core processing? Can you share the output of a nagiostats execution?

What process/documentation did you follow when installing the Nagios plugins suite on this remote machine hosting your MySQL instance? The Configure script used for compiling these plugins allows you to explicitly provide a path to the mysql client libraries ( ./configure --help for more info), whic...