Archive for the 'NRPE' Category

Monitoring Apache Cassandra Database Nodes with Nagios XI

As cloud services grow in popularity, so do the networks that provide those cloud services.  Few webserver-based distributed databases are as easy to install and configure as Apache Cassandra.  Apache Cassandra is an open source distributed database management system designed to handle large amounts of data across many commodity servers, providing high availability with no single point of failure. Cassandra offers robust support for clusters spanning multiple data centers, with asynchronous master-less replication allowing low latency operations for all clients.

Cassandra relies on the Java platform, and as those of you who have tried to configure Java app monitoring most likely know, the experience can be painful.  There are a handful of plugins on the Nagios Exchange that attempt to simplify the configuration.  As these plugins rely on the Apache Cassandra utility “nodetool”, you either need to install Cassandra on the Nagios server (which is not suggested) or use an agent (like NRPE) to run the plugin script directly from the Cassandra server (which should have the nodetool utility).

The Cluster Node Check is designed to verify whether the number of live nodes is less than a specified number, and if so trigger a warning or critical alert within Nagios.

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Major Improvements to Agent-Based Monitoring with the Release of Nagios Cross-Platform Agent — NCPA

Major improvements to agent-based monitoring have been taking place at Nagios Enterprises. NCPA, the Nagios Cross-Platform Agent, is a project that has the potential to revolutionize agent-based monitoring and increase the efficiency of IT support teams world-wide.

As many Nagios users know, monitoring with agents means juggling the installation of many different types of plugins to try and match devices, operating systems, and the basic functions of each agent. For example, in a simple agent-based Linux and Windows server environment you have to install 2 agents, know the 2 user manuals, there are 2 times the troubleshooting hours required, 2 times the commands on remote systems, 2 change logs to sift through for potential update breaks…the list goes on. It can be very difficult to keep organized and take a lot of time to implement and update your configuration, especially when your monitoring environment becomes larger and more complex.

Whether your environment is large or small, there are usually a myriad of devices that need to be monitored and more often than not, some sort of agent needs to be installed on these devices.

Wouldn’t it be simple if you only had to install one agent regardless of operating system or device?

We have been working on a project that aims to do this. Nagios Cross-Platform Agent (NCPA) is a fully contained agent that runs on Mac OS X, Windows, and Linux and seeks to solve all of the previously mentioned pitfalls of agent based monitoring with Nagios. The main goal of NCPA was to monitor the core metrics of a server and other devices without the added hassle of plugins and dependencies. Metrics such as CPU Usage, Disk Usage, Memory Usage, Interface Usage, Swap Usage, User Count, etc. are preloaded in NCPA so that all you have to do is install the agent. It has since broadened in scope to be a general purpose agent that is very good at doing the aforementioned job. Just install the NCPA agent on your system, and away you go.

Features & Benefits of NCPA:

-Installs on multiple platforms : Windows, Linux, Mac OS X and FreeBSD (untested on AIX, HPUX and Solaris)
-Real-time performance graphs and GUI configuration
-Fully contained agent, including dependencies
-Identical cross-platform configuration editing for both active and passive agents
-Minimizes knowledge needed to know down to one
-Advanced visual data representation

Direct links to the NCPA .exe and .rpm files can be found in the installation instructions which can be downloaded at the link below: Installing NCPA.pdf

We are very excited about this new agent and are currently looking for real world testers to try it out. To test NCPA please contact Thanks!

NRPE 2.15 Released – Now with IPv6 Support

NRPE 2.15 was released earlier today. The primary update in this version of NRPE is full support for IPv6.

The NRPE daemon now has the ability to listen on IPv4 and/or IPv6 addresses. In addition, the check_nrpe plugin now accepts switches that specify whether an IPv4 or IPv6 connection should be made to the NRPE daemon. The NRPE daemon has always had the ability to perform checks using IPv6, assuming the plugin it runs supports it. Thanks to Leo Baltus for the patch that made this possible.

IPv6 communication has been tested on Linux (RHEL/CentOS) and is known to work there. It also known to compile on other Unices that we have access to: Solaris 10, AIX 5.3 and 6.1 and HP-UX 11i v1. Feedback on these and other platforms is welcome. Bugs or enhancements (preferably with patches) can be submitted to Other discussion/questions can be sent to the mailing lists or