Configuration files Traditionally, Unix systems configuration were based on text files; you edit a file, sometime have to restart a service (rarely the entire system) and you’re in business. Most of the configuration files were located in the /etc folder. This paradigm is good when you have few servers to manage, but quickly becomes a hell above a dozen of servers: you have to manually edit the files which is error-prone and very time-consuming. Manual editing introduces differences between servers, proscribing the use of tool to help you. Configuration folders Linux authors suggested another approach: the configuration folders. The idea is simple: the main configuration file is only a skeleton with few parameters and commands to include files located in a folder (generally named xxx.d, in xxx is the configuration file). Apache users knows this paradigm for years. Examples: /etc/sudoers <-- main configuration file /etc/sudoers.d <-- configuration folder /etc/sudoer...