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:
Code: Select all
-t, --timeout=INTERVAL:STATE
INTERVAL Number of seconds before connection times out (default=30)
STATE Check state to exit with in the event of a timeout (default=CRITICAL)
Timeout STATE must be a valid state name (case-insensitive) or integer:
(OK, WARNING, CRITICAL, UNKNOWN) or integer (0-3)
In a nutshell, Nagios Core was unable to reach the agent on host XXXXXX after trying for 30 seconds.
To get more specific than that, we'd need to see the exact check_command you're running and have knowledge of exactly what check_nrpe is connecting to. It could be a standard NRPE server on a Linux box, an NSClient++ server running on a windows box, some windows port of NRPE, or some other bespoke server.