Successful automatic service detection

Treasure Hunt

Article from ADMIN 11/2012

By Bernd Erk

A lack of information about your infrastructure can result in faulty system configuration and other difficulties. Automatic discovery of all hosts and services would seem to be the best solution – but can it also prove itself in practice?

The term "autodiscovery" sounds promising and raises expectations: At the press of a button, a computer is supposed to piece together everything it needs from the web and then configure the appropriate monitoring system. Subsequently, all it has to do is sound an alarm if an incident occurs. However, things are different in practice. Neither Nagios nor Icinga has an autodiscovery function. However, if you want this functionality, you can take advantage of many useful tools available. In this article, I describe how.

Although often no Configuration Management Database (CMDB) or similar tool is provided for managing configuration settings, other sources of information are available. These could be lists of server hardware, DHCP and DNS entries, or inventory information from an Active Directory.

Tools from the manufacturer also frequently manage certain hardware, and this information often can be exported easily. For example, you can import the data from Cisco Works with the CLI utility or access the underlying database directly via JDBC.

The configuration of Nagios or Icinga can be divided into various files and subfolders. In one directory, for example, configuration files can be maintained manually, with automatically generated configurations kept in another folder. In this respect, configuration files are a very flexible medium.

Automatic Monitoring

If you have insufficient – or even no – information about the environment to be monitored, autodiscovery is a common way to take a first inventory of the infrastructure. Almost all autodiscovery tools work according to the same pattern: The admin specifies an IP range whose addresses are then scanned to find open ports and thus identify services running on them. SNMP queries also provide detailed information about components and status, especially for networks and hardware.

...

Use Express-Checkout link below to read the full article (PDF).