When active agent-based monitoring is not an option (because of a firewall, or security restriction), passive monitoring can provide the solution necessary to maintain network security and health. Today we will be discussing Nagios Remote Data Sender (NRDS) and how it can monitor Linux machines using passive check results. Passive results are sent to the Nagios Remote Data Processor (NRDP) server and processed in Nagios XI.
The NRDS client configuration can be managed centrally via the NRDS Config Manager Component in Nagios XI. Updated configuration files on the NRDS server are automatically picked up by all clients. The NRDS client runs on a cron job at a specified interval. Each time it runs, it will do the following:
- Run all of the commands, specified in the config file
- Send the results back to the Nagios XI server
- Check if there is a new version of the configuration file on the Nagios XI server, and if there is one, it will download it
- Download all of the plugins it needs from the server and install them on the client
In this article, I will show you how you can start monitoring a Linux host passively in three easy steps.
Step 1 – Adding Configuration
Go to Admin -> Monitoring Config -> NRDS Config Manager, click on Create Config, and select Linux from the Operating System drop-down menu.
Continue reading ‘How to Passively Monitor Linux Machines with NRDS & Nagios XI’
Now available 2 new clients to send passive check results to Nagios Remote Data Processor (NRDP) server.
We have just released:
send_nrdp.sh Bash NRDP Client
send_nrdp.py Python NRDP Client
You no longer need to install PHP or Perl on your client machines to run passive checks with NRDP. Both of these implementations can accept result piped from STDIN and you can change the delimiters to whatever you like.
STDIN results should be in the following order, for HOST checks:
for SERVICE checks
HOSTNAME SERVICENAME STATE OUTPUT
Additionally, the bash version can take an XML file of check results formatted like so:
<checkresult type="host" checktype="1">
<checkresult type="service" checktype="1">
Passive checks are extremely useful for integrating information from external applications and agents. They’re also the primary method of monitoring remote machines that are behind firewalls, proxies, and on private networks.
In an effort to simplify the setup of new remote agents and applications with Nagios XI, we developed a method for easily capturing and configuring new passive host and service check results.
Read How To Do it: Monitoring Unconfigured Objects With XI.pdf