1. Simulation Mode
The simulation mode allows you to make a dry run of your check_mk installation. It is enabled by setting simulation_mode to True in your main.mk:
simulation_mode = True
When simulation mode is enabled, then:
- target hosts are never contacted, neither by TCP, nor SNMP, nor datasource programs, nor by ping.
- instead, the data is always read from the cache files, if present.
- if no cache file is present, the check will go into UNKNOWN state.
- all IP addresses are hardcoded to 127.0.0.1, so no DNS lookups occur when creating the Nagios host definitions.
- thus any PING host check will just go to localhost.
- legacy_checks, custom_checks and active_checks - i.e. all active checks that are configured via Check_MK - are being replaced with dummy commands that just print a message and always are OK.
This all allows you to simulate a complex monitoring environment without have any real targets to monitor. All you have to do is to copy all configuration and runtime data from another installation to your test installation. The best way to do this is by using Check_MK's backup & restore mechanism.
After the restore, edit main.mk and set simulation_mode to True. As of version 1.1.10 you also can put this variable into local.mk. That configuration file will be read as very last and ist not touched by backup or restore.
user@host:~$ cmk -R Generating Nagios configuration...OK Validating Nagios configuration...OK Precompiling host checks...OK Reloading Nagios...OK
After this access the site via your web browser and you should find your whole Nagios setup is running in simulation mode.