jWatchdog delivers a simple watchdog to actively monitor your infrastructure and send you notifications in case something goes wrong. It is configured using a simple XML configuration file. This configuration file can be changed on-the-fly without a need to restart the watchdog. jWatchdog does not offer data collection itself. It assumes that you already collected the data on which you want to run jWatchdog. The de facto standard tool Collectd is recommended for data collection. jWatchdog assumes that you use the RRDTool collectd output plugin to store the collected data in RRD files, or use Graphite as a datasource.