The magics of configuration management

There are some magics in configuration management world.

First of all, I’d like to mention hiera, which is a component of Puppet. The magic of hiera is as the name indicated, it allows a hierarchy to be applied. The hierarchy defined different levels of priorities, the higher higher level hierarchy will overwrite lower level configuration. This is really useful when it comes to custom some specific stuff based on generalized settings.

Secondly, I’d like to talk about code reuse. The idea and concept is actually wide spread in programming world. Puppet uses puppet class to parse a bundle of actions to be reused , while Ansible uses Ansible roles. Programming in this area might not be too much related to logic, but structure and organization are pretty important.

Another magic that I want to talk about is reference, we know that any language has references and we know that top-level variables can be used anywhere. This is very useful when it comes to username and password management, cause normally a system contains multiple component. We call it system integration when we combine them. Eg, a web server uses MySQL access info to contact with MySQL databases. If there are multiple types servers like web servers, java backend servers need to talk to the same database, it might be a good idea to promote the access info into a global variable.

OK, generally speaking, it is not that hard to manage infrastructure if you have a thorough understanding of the code.