Nagios 3 introduces a very powerful feature called adaptive monitoring that allows the modification of various check-related parameters on the fly. This is done by sending a command to the Nagios external command pipe.

The first thing that can be changed on the fly is the command to be executed by Nagios, along with the attributes that will be passed to it — an equivalent of the check_command directive in the object definition. In order to do that, you can use the CHANGE_HOST_CHECK_COMMAND (visit http://www.nagios.org/developerinfo/externalcommands/commandinfo.php? command_id=107) or CHANGE_SVC_CHECK_COMMAND (visit http://www.nagios.org/developerinfo/externalcommands/commandinfo.php? command_id=108) command. These require the host name, or the host name and service description, and the check command as arguments.

This can be used to actually change how hosts or services are checked, or to only modify parameters that are passed to the check commands — for example, a check...