The Watcher

With a convenient web interface and a flexible design, the Zenoss monitoring tool is winning converts around the world. Zenoss has an impressive list of features that seem to grow every month. The tool does a great job as a status monitor, and it even supports Nagios plugins. The Zenoss system is also good for monitoring performance and trending (Figure 1). The tool comes stocked with defaults for various types of devices, such as Linux boxes, switches, routers, and even Windows machines, and additional features are easy to add. In the grand tradition of *nix environments, Zenoss is designed with a modular architecture. To add new functionality, just plug in a new module (a ZenPack, in the parlance of the Zenoss masters).

Syslog Server

One function I find especially useful is Zenoss' syslog server. Zenoss will take standard syslog output and act as a syslog server. This means that, in addition to checking status and monitoring performance, you can also view log information, which is often the best way to see cause and effect. Your Windows machines aren't left out of the logging loop either because Zenoss handles Windows event logging via WMI (Windows Management Instrumentation.

Protocols

Zenoss supports monitoring and management technologies such as SNMP, WMI, ping, portscan, and ssh-based monitoring.

SNMP is the defacto standard for garnering network information, and virtually all computing or networked devices support SNMP.

For devices that don't use SNMP or WMI, or that are beyond the access of conventional monitoring tools, you can perform limited network tests with ping- or portscan-based monitoring.

Monitoring via ssh lets Zenoss connect to a machine and execute commands to determine a machine's status.

Interfaces

Zenoss offers several avenues for communicating network information. The first option is the web interface. The most useful view of what is happening on your network is the Event Console (Figure 2), which provides an interface for viewing and configuring monitoring events.

Most people, however, are not likely to be watching the event console all of the time. Thankfully, Zenoss can push out alerts to SMS and email. What's really fabulous is the granularity you can apply to alerts. For instance, a mail admin might want to know about a problem with a mailserver anytime, but other network problems only during the business day. Zenoss makes it quick and easy to configure a range of alerts for a range of different events.

Another Zenoss tool for viewing network data is a desktop applet called Zapplet. This applet provides status and event information in your system tray. Zapplet runs on just about anything that supports Gtk2.