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.