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Agents
  
Agents
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.
Agent
Environment
op5 NSClient++
Microsoft Windows
NRPE
Unix/Linux
MRTGEXT
Novell
Windows SyslogAgent
Microsoft Windows
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.
op5 NSClient++ runs as a service under
Windows 2000
Windows XP
Windows 2003
Windows 7
Windows 2008.
Windows 2008 R2
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
check_nrpe
check_nt
This plugin is used for all basic tests like
cpu
memory
disks
But it can also be used to check
Windows services
performances counters
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:
NSC.ini
op5.ini
custom.ini
They are located in the install directory.
Table 1 Description of the configurations files
 
File
Description
NSC.ini
This is the standard configuration file. This contains the default settings for NSClient++
This file might be overwritten during an update of NSClient++
op5.ini
This is a op5 specific configuration file. Here are the changes made by op5 entered.
This file might be overwritten during an update of NSClient++
custom.ini
This is where you shall place your own files.
It will never be overwritten during any update of NSClient++.
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: If a non default port is used you also need to make changes on the op5 Monitor server.
[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 Adding a custom script/plugin to NSClient++
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
rpm-packages
deb-packages
portable source-code.
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 Download the package for your environment from the download section at the support site at www.op5.com
2 Put the package to the host you like to install it on.
3 Install the package the same way as you do normally with packages on that host.
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:
/etc/nrpe.conf
Table 2 NRPE main configuration file settings
Setting
Description
server_port
The port NRPE should listen on.
Default: 5666
allowed_hosts
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
Make sure you do not add any space between the comma (,).
 
Default: empty
nrpe_user
The user the NRPE daemon is executed as.
Default: nobody
nrpe_group
The group the NRPE daemon is executed as.
Default: nobody
debug
Set to 1 if you need to debug the NRPE.
Default: 0
command_timeout
The default time out, in seconds, a check shall have.
Default: 60
dont_blame_nrpe
Set to 1 to be able to send arguments to NRPE.
Default: 0
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 NRPE command parts
Part
Description
command[name]
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.
Do not use space in the command name.
/opt/plugins/...
This is the command line used to execute the plugin you are going to use in your command.
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 Login to the host you have installed NRPE on as root user over ssh.
2 Create a new configuration file and open it up with your favorite editor.
3 Add a command line looking like this:
command[proc_smsd]=/opt/plugins/check_procs -w 1: -c 2:2 -C smsd
4 Save the file and restart NRPE:
service nrpe restart
Plugins used with NRPE
The only plugin used with NRPE is
check_nrpe
To use the plugin with the command defined in Adding commands to NRPE on page 18 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:
-port=<port>
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.
-debug
will enable some debugging output to the System Console screen. This is only really useful when you are first configuring the extension.
-mla=<license>
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
Windows 2000
Windows XP
Windows 2003
Windows 2008.
Windows 2008 R2
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.