This page reviews how to use WMI agentless plugins and is valid for use with any version of GroundWork Monitor. Further, those customers using GroundWork Distributed Monitor Agent (GDMA) may find the description of plugins and WMI troubleshooting sections useful.
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Windows Management Instrumentation (WMI) is a management standard technology for accessing management information and automating administrative tasks in an enterprise environment. There are two main systems management architectures; Agent-based where the proprietary software agent is loaded on a managed system and, Agent-less which depends on management functionality that is built into a managed system.
This project consists of a collection of script monitors (.vbs for starters) that use the Microsoft .NET Framework and WMI to retrieve performance data from remote Windows hosts without the need for agents on the remote hosts. Initially we have about 20 scripts, although it is a fairly minor matter to script others.
There are large numbers of WMI Classes on Windows hosts. This plugin package with a small change to each plugin can be used to retrieve almost any parameter of interest in the default WMI namespace. There is no need for agents on the remote hosts.
The plugin package comes with an NRPE configuration file that can be included from the base nrpe.cfg file. Some of the plugins retrieve specific properties such as CPU load percentage, disk utilization, disk and network I/O, etc., while others are for retrieving arbitrary properties from WMI. The provided NRPE configuration file defines NRPE commands using the plugins to get both specific and arbitrary properties and there are documented syntax examples for each command.
Plugins are configured to return performance data where it makes sense which facilitates easy graphing of results on a Nagios server.
A typical monitor works like this:
This script returns a string to stand out that says something like:
The warning and critical thresholds will be passed as command line arguments (in percent).
In addition it returns an exit value like this:
All scripts return syntax and help if passed the --help command line option. And all scripts return performance data formatted according to the Nagios Plugin Developer's Guidelines.
The following table lists and describes plugins in the package.
|check_100nsec_timer.vbs||checks WMI counters of type 'PERF_100NSEC_TIMER'|
|check_counter_bulk_count.vbs||checks WMI counters of type 'PERF_COUNTER_BULK_COUNT'|
|check_counter_counter.vbs||checks WMI counters of type 'PERF_COUNTER_COUNTER'|
|check_counter_large_rawcount.vbs||checks WMI counters of type 'PERF_COUNTER_LARGE_RAWCOUNT'|
|check_counter_rawcount.vbs||checks WMI counters of type 'PERF_COUNTER_RAWCOUNT'|
|check_cpu_load_percentage.vbs||checks load percentage of one or more CPUs|
|check_disks_io.vbs||checks disk I/O of one or more logical disks|
|check_disks_percentage_space_used.vbs||checks disk usage of one or more logical disks|
|check_memory_percentage_space_used.vbs||checks RAM, page file, or total memory usage|
|check_network_io.vbs||checks network I/O of one or more TCP/IP network interfaces|
|check_proc_num.vbs||checks number of running processes matching a search expression|
|check_raw_fraction.vbs||checks WMI counters of type 'PERF_RAW_FRACTION'|
|check_services_states.vbs||checks the state of an installed service|
|get_computer_info.vbs||enumerates information about processors, installed services, running processes, network interfaces, and logical disks for use in configuring other plugins|
|get_counter_type.vbs||enumerates information about WMI classes and properties to determine which counter plugin to use|
|get_system_uptime.vbs||checks system uptime and enumerations information about the hardware and OS|
|verify_wmi_status.vbs||checks OS version to verify WMI is working|
- NRPE_NT version 0.8b. The remainder of this document assumes that NRPE_NT has been installed under C:\NRPE_NT with the executable and configuration file under C:\NRPE_NT\bin. It also assumes that you have tested correct operation of NRPE_NT by calling it with the check_nrpe Nagios plugin from your Nagios server. Version 0.8b is necessary in order to fully support specification of some special characters when calling NRPE_NT from check_nrpe. NRPE_NT can be downloaded from Sourceforge.
- Nagios 2.x or later with check_nrpe plugin compatible with NRPE_NT version 0.8b. Nagios can be found at www.nagios.org.
- Once you have installed NRPE_NT on a host (designated as <host>) and tested that it can be called from your Nagios server with a check_nrpe -H <host> create the following directories:
- Copy all of the VBS programs from this directory into:
- Copy the file V2_nrpe_commands.cfg into:
- Edit C:\NRPE_NT\bin\nrpe.cfg and append the following line to the bottom:
- Restart the NRPE_NT service.
After completing the installation procedure you should be able to call each of the installed scripts with the commands defined in V2_nrpe_commands.cfg either from the Windows server itself or from the Nagios server using check_nrpe.
- On the Windows server you installed NRPE_NT and the plugins on, open a command window and type:
The output you get should look something like:
This indicates that the plugin was able to successfully talk with the WMI service on 127.0.0.1 and retrieve the OS version.
- On the Nagios server, type the following command in a shell once you have changed directory to the location of the check_nrpe plugin:
The output you get should look something like:
You have just executed the same verify_wmi_status.vbs plugin but through the NRPE_NT service from your Nagios server.
The following example Nagios command and service definitions assume you have Nagios 2.x or later installed with a version of check_nrpe compatible with NRPE_NT v0.8b. They also assume that $USER1$ points to the directory containing check_nrpe, and that $USER21$ is the address of the host on which NRPE_NT is installed! Download information about both Nagios 2.x (or later) and NRPE_NT v0.8b is available in the install document referenced below.
For a list of further examples refer to the NRPE_NT configuration file available for download below. One key point is that you can reverse warning and critical thresholds and have match in the reverse sense, (e.g., If you set -w 80 -c 50 and the returned value is 90 the return code will be 0 (OK)).