Quick Start: Make sure you have UCD SNMP 3.6.2+ (libraries) and the Perl SNMP module installed (http://www.cpan.org/misc/cpan-faq.html) Copy snmpvar.mon to your mon.d directory Copy snmpvar.def to /etc/mon, add your own variables Copy snmpvar.cf to /etc/mon and edit to match your needs Test from mon.d directory with ./snmpvar.monitor -l host1 host2 ... Test again from mon.d directory with ./snmpvar.monitor host1 host2 ... Add watch/service to mon.cf, using snmpvar.monitor Commandline options: --varconf=/path/to/snmpvar.def if neither /etc/mon nor /usr/lib/mon/etc --config=/path/to/snmpvar.cf if neither /etc/mon nor /usr/lib/mon/etc --community=your_SNMP_read_community if not 'public' --groups=Power,Disks test only a subset of variables for a host group --timeout=n SNMP GET timeout in seconds --retries=n number of times to retry the SNMP GET --debug tell what config is being useed --mibs='mib1:mib2:mibn' load specified MIBs --list[=linesperpage]] produce human-readable listing, not alarms For every host name passed on the command line, snmpval.monitor looks up the list of variables and corresponding limits in the configuration file (snmpmon.cf). If a --groups option is present, only those variables are checked which are in one of the specified groups. To specify more than one group, separate group names with commas. You can also exclude groups by prefixing the group name(s) with '-'. Don't mix in- and exclusion. Examples: --groups=Power only vars in the Power group --groups=Power,Env vars in the Power or Env group --groups=-Power,-Env all vars except those in Power or Env groups --groups=Power,-Env won't work (only the exclusions) For every such variable, it looks up the OID, description etc. from the variable definition file (snmpvar.def). This monitor looks for configuration files in the current directory, in /etc/mon and /usr/lib/mon/etc. Command line option --varconf overrides the location of the variable definition file, option --config sets the configuration file name. When invoked with the --list option, the output format is changed into a more human-readable form used to check and troubleshoot the configuration. This option must not be used from within MON. Exit values: 0 if everything is OK 1 if any observed value is outside the specified interval 2 in case of an SNMP error (e.g. no response from host) Basic Troubleshooting: use snmpvar.monitor --list option to see variable values use snmpwalk your_hostname public .1 | less to verify SNMP agent The snmpvar.def File: In this file we define variables that can be retrieved via SNMP. In a way, the .def file is snmpvar.monitor's idea of a MIB. Entries consist of a "Variable variable-name" declaration Variable PE4300_TEMP_MB [NOTE: The variable name cannot be "Host" or "FriendlyName"] followed by the mandatory specification of Object ID and Description: OID .1.3.6.1.4.1.674.10891.300.1.5.2.2.1.3 Description Motherboard Temperature It is suggested that OIDs be entered numerically as shown above in order to eliminate the need for having the SNMP libraries compile the relevant MIB files on every invocation of the monitor. By default, this monitor loads no MIBs. If you want to use symbolic OIDs, use the --mibs commandline option to specify which MIBs you need. By the author's convention, an OID describing an array of values, like ifOperStat which takes the interface number as an index, is written with a trailing dot, while OIDs of scalars end in a number. As of version 1.1.1, the monitor will insert the dot before the index if you forgot it in the .def file. Optional Elements of a Variable definition: DefaultIndex 3 4 5 A list of indices to test by default. Let's say the OID is .1.2.3. and DefaultIndex is "18 22 36", then the monitor will retrieve the values of .1.2.3.18, .1.2.3.22 and .1.2.3.36 when testing this variable, and will compare them all against the limits. Where necessary, the DefaultIndex can be overridden for one host/variable combination, using the Index statement in the .cf file. FriendlyName 3 Disk Fan 1 This lets you replace the standard display of "Variable [Index]", e.g. "Fan Speed [5]", with individual labels for each index. The FriendlyName option is typically specified in the .def file for items that have the same name for every use, e.g. component names like in the case of fans, power supplies etc. The same option exists in the .cf file to name a particular variable on a particular host, e.g. to display a line name instead of an interface number on a router. If the FriendlyName string begins with "@", the Description is substituted for the "@". Scale / 10.0 A formula to re-scale the value returned from the host. The expression is appended to the raw value and the resulting expression is evaluated by Perl. The raw value is available as $rawval if necessary. Unit C Used in value display / messages, Decode 1 unknown Decode 2 OK Decode 3 FAILURE Values retrieved through SNMP are often enumerations of status codes. The Decode statement lets you put text labels on these values. DefaultGroup Environment Defines that all, by default, instances of this variable go into the specified group. Individual overrides possible in .cf file. The snmpvar.cf File: In here, you "call up" the variables to be retrieved for a particular host. Entries consist of a "Host host-name" declaration followed by at least one "variable-name [options ...]" line. Host ntserv1 This hostname corresponds to the hostname on the command line, i.e. the hostname you used in MON's hostgroup statement. FOO_FAN_RPM Min 1000 Max 5000 MaxValid 10000 Index 1 2 3 4 This example uses almost all options. It instructs the monitor to retrieve the OID specified under "FOO_FAN_RPM" in the .def file. Min 1000 specifies a minimum value, measured >= minimum Max 1000 specifies a maxcium value, measured <= maximum If the measured value is outside of these limits, a failure is reported. To test for "Value = X", use "Min X Max X". MinValid -1 MaxValid 10000 Some monitoring hardware occasionally measures garbage. To avoid triggering an alarm when this happens, you can use MinValid/MaxValid to specify the range (inclusive) of plausible values for this variable. If the measured value exceeds these limits, only a warning will be generated, but no failure will be reported to MON. Group Environment Puts this particular variable into the specified group. Groups are used to test a partial set of the variables specified for a host, by using the --groups= command line option. Index 1 2 3 This tells the monitor which object instances (array elements) to test in case of a non-scalar object. Since the list of indices can be as long as necessary, the Index option must be the last one on the line (after Min X, Max Y etc.) The list specified as DefaultIndex in the .def file entry for this variable is used unless Index is pecified here. When retrieving a non-scalar value, the snmpvar.monitor will normally display the instances (array elements) by appending their index to the description, as in "Line Status [3]". Often, it is desirable to label individual instances in a more mnemonic way. To do this, you can add a number of FriendlyName directives after a variable request, like this: Host firewall IF_OPERSTAT Index 1 2 3 FriendlyName 1 1: Leased Line FriendlyName 2 2: DMZ FriendlyName 3 3: Internal Router In this case, the monitor checks the ifOperStat for interfaces 1, 2, and 3 on host "firewall". If interface 3 were not "up", the monitor would signal a failure of "Internal Router" instead of "ifOperStat [3]". If the FriendlyName string begins with "@", the Description is substituted for the "@". If all instances of this variable having the same index have the same meaning regardless of what host they are on, you can put the FriendlyName statement into te respective variable definition in the .def file instead. The snmpopt.cf File: This optional file is used to pass parameters to the SNMP library. For SNMPv1, this is generally not necessary unless the target's SNMP port differs from the default (161). Note that SNMPv1 community string, timeout and retries can also be specified on the snmpvar.monitor command line, overriding whatever default or configuration file setting. You will need to edit this file in order to use SNMPv3.