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VERSION
This document describes version 0.7beta of check_csl, released
March 16, 2006.
SYNOPSIS
check_csl.pl option=value [switch(es)]
Available options are:
-f,--file Configuration file name - required;
-t,--timeout Plug-in timeout in seconds;
Available switches are:
-V,--version Plug-in version;
-v,--verbose Verbosity level (up to 3);
-h Usage help;
--help Manual help.
DESCRIPTION
check_csl runs necessary checks and according to defined conditions, interprets results and returns service
level - OK, Warning or
Critical.
Calculation conditions
are written to configuration
file in form
of formula. Also information about checks, executed by plug-in, is
included in same configuration file. It is also possible to specify custom plug-in runtime timeout and desirable verbosity
level.
Configuration
File
Configuration file consists of two
sections: formula section, according which the final
result will be calculated, and checks description section, where checks executables are written. Comments, beginning with comment sign # are allowed.
Formula
Section
Formula section must begin from
first uncommented configuration file line. Formula contains expression, which may consist of
variables, operators and parentheses. Variable keeps state of a particular
check, operators describe the way
results will be interpreted, and parentheses change the expression execution priority.
Variables
Check variable keeps calculated check's state. Every different check must have
one and only
variable. Information about what check
variable is related to is kept in Check's description
section. Name of the variable must
contain only ``word'' symbols (alphanumeric or _), no white spaces are allowed. Names are case-sensitive. Variables are separated between each other with
operator sign or parentheses too. Variables keep OK,
Warning
or Critical values.
Operators
Within calculations two types of
operators are used: logical OR marked with + sign and logical AND marked with * sign. logical AND operator has higher priority
level than logical OR operator. Execution priority may be changed with parentheses.
If expression contains two variables
and operator sign, the calculated
result would be:
1 var's value: OK OK OK Warning Warning Critical
2 var's value: OK Warning Critical Warning Critical Critical
Result of "+": OK Warning Warning Warning Warning Critical
Result of "*": OK Warning Critical Warning Critical Critical
Parentheses
Parentheses change the order of
operations. Covered expression will be evaluated first. If there are nested
parentheses, the expression covered with inner parentheses
is evaluated first. Overall:
·
If expression
has parentheses, the covered expression
is evaluated first.
·
Result of logical AND is calculated.
·
Result of logical OR is calculated.
Checks Section
In the Check's description section the check's
variable name, check's full path to the
executable, and short description (not required), are written. This section
must begin with first uncommented
line after the Formula section.
Check's
variable
Every check variable is written
on the separate
line. Requirements for the variable names
are written in Variables section.
Check's
executable
After the variable's name and equation sign = follows the path to check's
file and its arguments. Nagios must have
proper permissions to execute check.
Check's description
Since availability level calculations may include same
check's names with different arguments, the use of check's
file names for short description
is not convenient.
Also, using the variable's name for short check description
may not be convenient either. Therefore explicit short check description
is allowed after the exclamation
mark !. It is possible to specify distinct variable name or include a short check description.
Example of
Configuration File
###################################################################################
# #
# Start of Formula's section #
(a+b)*host3
# #
# End of Formula's section #
###################################################################################
# #
# Start of Check's Description section #
# #
a=/usr/share/nagios/plugins/check_ping -H google.lt -w 100,10%% -c 200,20%% !google
b=/usr/share/nagios/plugins/check_ping -H cisco.com -w 150,30%% -c 400,80%% !cisco
host3=/usr/share/nagios/plugins/check_ping -H 192.168.0.1 -w 30,5%% -c 50,50%%
# #
# End of Check's Description section #
# #
# The expression above shows, that the availability level can be achieved if right#
# host3 availability level and one of the google or cisco availability levels #
# condition met. #
###################################################################################
Runtime
Timeout
All plug-ins have limited runtime,
and the default
timeout value is specified in
the Nagios configuration file. It is possible to specify explicit timeout value in
seconds with option --timeout. Since every check is
run in separate
thread, when plug-in timeouts because of timeouted
check, it detaches all threads, leaving
them work by their own
until they're done, and exits
with state UNKNOWN.
This feature is highly experimental.
With default verbosity level plug-in produces single line output: Ok, Warning or Critical.
With first verbose level plug-in returns
single line output with additional information: short check's description, which returned state Warning
or Critical.
With second verbose level plug-in produces
multi line output, specifying on each
separate line which checks returned state Warning
and Critical and what arguments were they called
with.
If plug-in is run under
third verbosity level, it generates multi line output, additionally including check's generated output.
AUTHOR
Jelena Osadciaja ( elenute
AT gmail DOT com)
COPYRIGHT AND LICENCE
check_csl is licensed under the terms of
the GNU General
Public License Version 2 as published
by the Free
Software Foundation.
Like Nagios itself, check_csl is provided AS IS with NO
WARRANTY OF ANY KIND, INCLUDING THE WARRANTY OF
DESIGN, MERCHANTABILITY, AND FITNESS FOR
A PARTICULAR PURPOSE.