In this recipe, we'll configure the Nagios Core server to check its own disk usage and to flag a
CRITICAL state depending on how little free space is left on the disk. We'll accomplish this by adding a new service to the already defined
localhost host called
DISK, which will run the
check_local_disk command to examine the state of the mounted volumes on the server.
Because burgeoning disk usage can creep up on any system administrator and because of the dire effect it can have when a disk suddenly gets filled completely without any warning, this is among the more important things to monitor in any given network.
For simplicity, we'll demonstrate this only for the monitoring server itself, as a host called ...