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Agents

Agents
About agents
This chapter covers the following topics:
Introduction
Most of the monitoring in op5 Monitor is used with the help of agents. The plugins are contacting the agents and let them do the job.
There are mainly four agents available for download at the op5 support site.
op5 NSClient++
This is the agent used for monitoring Windows type operating systems.
This agent has the ability to function as a drop in replacement for NSClient providing the same features as NSClient combined with the ability to execute scripts on the monitored Windows server.
Installing and configuring op5 NSClient++
The installation and configuration of op5 NSClient++ is covered in detail in the op5 video tutorial How to monitor windows servers:
http://www.op5.com/support/documentation/video-tutorials
Plugins used with op5 NSClient++
There are mainly two plugins that is used to communicate with op5 NSClient++:
*
*
check_nt
This plugin is used for all basic tests like
*
*
*
But it can also be used to check
*
*
check_nrpe
check_nrpe can also be used in the communication with op5 NSClient++. This one is normally used when you are performing checks on the Windows server with custom scripts.
Configuration files
NSClient++ operation is configured in a couple of plain text files called:
*
*
*
They are located in the install directory.
Table 1
 
The default configuration provided is fully functional but there are some options that likely need to be changed.
Changing the configuration
To change the configuration
To change the configuration open the custom.ini file using your favorite text-editor (e.g. WordPad). This file is empty and but take a look at NSC.ini to view all settings.
Read the NSC.ini file carefully to get a complete understanding of all configuration options. Lines starting with ; (semicolon) are comments.
Before the changes will take effect NSClient++ must be restarted.
Options most likely in need for configuration are described bellow, section by section.

[Settings]
allowed_hosts=
This option lists all servers that are allowed to talk to the agent. Enter the IP-address of the op5 Monitor/Statistics server. If this option is left blank anybody will be able to communicate with the agent.
[log]
debug=0
Set debug to 1 to enable debugging. This is normally not needed but can be very useful when debugging.
[NSClient]
port=1248
This is the port used for NSClient style requests, i.e. using the check_nt plugin. If any other application is already using the default port it might be necessary to change this option.
Note:
[NRPE]
port=5666
This is the port used for nrpe style requests. In order for a minimum of configuration on the op5 Monitor server it’s recommended that this option is left with the default value. If this is changed new nrpe check commands using the configured port need to be created on the op5 Monitor server.
allow_arguments=0
Set this to 1 to enable the possibility to include arguments in nrpe requests. This could be considered a security risk so only enable this if needed. Also, make sure to set the allowed_hosts option described above if arguments are allowed.
[NRPE Handlers]
The nrpe handlers provide a way to execute any custom plugin/check command on the monitored Windows server. In this section you configure all the commands that should be available.
Example 1
command[my_custom]=c:\mycustomdir\my_prog.exe
Or the simplified syntax:
my_custom=c:\mycustomdir\my_prog.exe
 
 
NRPE
NRPE is a Unix client for executing plugins on remote hosts.
It is distributed as
*
*
*
NRPE is used in combination with a set of local plugins. By default in op5 Monitor the plugins are placed in:
/opt/plugins
 
There are only a few plugins shipped with the op5 NRPE packages but you may use the ones located on the op5 Monitor server.
 
Installing NRPE
To install NRPE
1
2
3
Configuring NRPE
Before we can start use the NRPE agent for monitoring with op5 Monitor we need to configure the agent.
The NRPE agent is located in:
*
Table 2
Default: 5666
Add the IP of you OP5 Monitor server on this line multiple addresses can be separated with , ie: allowed_hosts=1.2.3.4,1.2.3.5
Default: empty
Default: nobody
Default: nobody
Set to 1 if you need to debug the NRPE.
Set to 1 to be able to send arguments to NRPE.
Adding commands to NRPE
NRPE comes with a few predefined commands. Those commands are located in:
/etc/nrpe.d/op5_commands.cfg
You may add your own commands and you should do that in your own file in:
/etc/nrpe.d/
You must set .cfg as extension to your configuration file or else it will not be loaded into NRPE when the daemon is restarted.
 
NRPE command definition
The NRPE command definitions is divided into two parts.
Table 3
The string between the square brackets will be the name of this command. The name is used when you executes the command with check_plugin.
To add a command to NRPE
Here we will add a command that is looking for a process named smsd using the plugin check_procs, which is installed by default.
1
2
3
Add a command line looking like this:
command[proc_smsd]=/opt/plugins/check_procs -w 1: -c 2:2 -C smsd
4
Plugins used with NRPE
The only plugin used with NRPE is
*
To use the plugin with the command defined in Adding commands to NRPE on page 11 you shall use the following command line in your service definition:
/opt/plugins/check_nrpe -H $HOSTADDRESS$ -C proc_smsd
 
Novell
MRTGEXT was originally written as an NLM for Novell Netware to obtain values used with the widely known MRTG (predecessor of cacti, which is the base of OP5 Statistics), but it can also be used to poll values from op5 Monitor.
Installing Novell MRTGEXT
To install this extension, simply copy the MRTGEXT.NLM to each NetWare server's SYS:SYSTEM directory that you wish to gather statistics from. Then edit the server's AUTOEXEC.NCF to “LOAD MRTGEXT” so it will load each time the server is restarted.
The MRTGEXT.NLM has three command line switches available:
*
will change the port that MRTGEXT listens on for statistic requests. By default, MRTGEXT will use port 9999. For example, to have MRTGEXT use port 1023, add -port=1023 to the load line. If you change the port number on the command line, be sure to modify the perl script as well.
*
will enable some debugging output to the System Console screen. This is only really useful when you are first configuring the extension.
*
For those with an MLA license (mostly for NetWare 5), the MRTGEXT.NLM currently can not obtain a valid value for the server license count. Using this option will tell the MRTGEXT.NLM the license count max to report. This is important if you use the NWEXTCFG.PL to create configuration files or if you use the servstat.pl script. For example, if you have a NetWare 5 MLA license and you really only have a 100 user server, then you would add -mla=100 to your load command line.
More information
For more information please read here:
http://download.op5.com/agents/novell/1.46b/readme.txt
Windows SyslogAgent
op5 SyslogAgent runs as a service under
*
*
*
*
It formats all types of Windows Eventlog entries into syslog format and sends them to a syslog host (The op5 Monitor server or the op5 LogServer). The agent can also forward plaintext log-files.
Introduction
The entries in the Event log are sent to the op5 Logserver or op5 Monitor server. Text based application logs are also supported.
The op5 SyslogAgent is a repackaged version of the Datagram SyslogAgent, which initially is a bug fixed version of Sabre Net's old NT_Syslog. The op5 SyslogAgent is licenced as GPL software.
Installation
The op5 SyslogAgent installation package consists of an msi installer. To install simply double click the installation msi file and follow the on-screen instructions.
By default the op5 SyslogAgent will be installed in an op5 subdirectory to the program files folder. Usually:
C:\Program Files\op5\SyslogAgent\
 
You will also have the possibility to choose if you want to create start-menu, desktop and quick launch shortcuts to the SyslogAgent-configuration tool.
After the installation is completed you will be asked if you want to start SyslogAgentConfig. If you don't do this the agent won't be configured and cannot be started. If you choose to start the
SyslogAgent configuration continue to the section.
Upgrading
If a prior version of the SyslogAgent is installed it should, to avoid problems, be stopped and
uninstalled as a service and then uninstalled. Stopping and uninstalling the service can be done
from the SyslogAgent Configuration tool. Follow these steps to stop and uninstall the
SyslogAgent service:
1. Start the SyslogAgent Configuration tool
2. Press the “Stop”-button (see Fig 3. in the section Configuration)
3. Press the “Uninstall”-button
After the service have been stopped and uninstalled you should uninstall the previous version of
the SyslogAgent from “Add/Remove software” on the windows control panel.
Now you can proceed with the installation of the new version as usual. Note that your previous
settings will be used directly when the installation is complete.
Configuration
When the configuration tool is started the following window should be displayed:
Configuring the elementary functions
To configure the elementary functions and start the SyslogAgent started follow the following steps:
1
Press Install, this will install the SyslogAgent as a service.
2
Enter the IP address in the field Syslog Server:. This IP should be the one to your op5 Logserver or op5 Monitor server.
3
Make sure the check box “Enable forwarding of event logs” is checked.
4
Press Start Service.
Your SyslogAgent is now configured and should be sending logs to your op5 Logserver or op5
Monitor server.

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