Check Parameters

During inventory Check_MK creates checks (Nagios services) for items that should be checked. These checks are written to text files in /var/lib/check_mk/autochecks/*.mk. The question that soon arises is: how can I configure parameters for those checks? How can e.g. warning and critical levels for filesystems checks?

There are several ways to do that:

• Creating manual checks instead of inventorized checks (using the variable checks).
• Using the config variable check_parameters (available since 1.1.7i4).
• Setting check specific global default values.
• Deprecated since 1.1.7i4: using check specific special configuration such as filesystem_levels.

The general way how check parameters are applied is:

1. If the check is defined manually via checks, parameters given there are used, regardless of any other settings.
2. If the check has been created by inventory, then the rules in check_parameters are applied (see below).
3. If no rule in check_parameters applies, then a check specific configuration variable for system wide default levels is consulted, if you have defined that in main.mk. For example for filesystem checks such a levels can be defined with:
main.mk

filesystem_default_levels = (90, 95)

4. As a last resort each check has hard coded global default parameters. For example all filesystem checks (e.g. df or df_netapp) have global default levels of (80, 90). Information about that can be found in the checks man pages.

With the configuration variable check_parameters you can define rules for check parameters, using host names, host tags and service descriptions. The syntax is the same as in many other cases in Check_MK, for example as in service_groups.

Here is an example for defining filesystem levels:

check_parameters = [
 # (1) Filesystem C: on winsrv02 gets levels (92, 96)
 ( (92, 96), [ "winsrv02" ], [ "fs_C:" ]),

 # (2) Filesystems on hosts with tag 'sap' and 'test' are always OK
 ( (101, 101), [ 'sap', 'test' ], ALL_HOSTS, [ "fs_"]),

 # (3) Levels for filesystems below /sap (also /saptrans, /saptest)
 ( (80, 95), ALL_HOSTS, [ "fs_/sap" ]),

 # (4) Levels for filesystems /var and /tmp on all hosts
 ( (90, 95), ALL_HOSTS, [ "fs_/var$", "fs_/tmp$" ] ),

 # (5) Set levels for all remaining file systems to 80% / 90%
 ( (80, 90), ALL_HOSTS, [ "fs_" ] ),
]

Please note, that:

• The service expressions are always matched against the beginning of the service name. They are regular expressions. Use a $ to denote the end.
• If a service description matches more than one rule, the first match wins. So the most specific rules (the exceptions) must be appear first.
• Make sure that the parameters are in the format expected by the specific check. Please refer to the check manual of the check in question (check_mk -M).
• These rules only apply on checks found by inventory. For example the rule (3) applies only to hosts which actually have a filesystem beginning with /sap.