Essential System Administration, 3rd Edition

Automating Complex Configuration Tasks with Cfengine

Cfengine is a wonderful tool for configuring and maintaining Unix computer systems. MarkBurgess, the author ofCfengine, describes it as follows:

Cfengine, or the configuration engine, is an autonomous agent and a middle to high level policy language for building expert systems which administrate and configure large computer networks. Cfengine uses the idea of classes and a primitive intelligence to define and automate the configuration and maintenance of system state, for small to huge configurations.

What’d he say? Using Cfengine means that you’ll have to get used to some unfamiliar jargon, but it’s worth it. Basically, what Mark is saying is that Cfengine is a standalone tool (set of tools) that administers and configures computers according to the instructions in its configuration files. The configuration files describe the desired characteristics of various system components using a high-level language which is easy to learn and use (and involves no programming). In this way, Cfengine can automatically bring one or a very large number of systems into line with each one’s individually defined configuration specifications. It can also make sure they stay that way by monitoring them and correcting them as needed on an ongoing basis.

In more practical terms, the following list will give you some idea of the breadth of administration and configuration tasks thatCfengine can automate:

• Configure the network interface.

• Edit system configuration ...