Technique editor

A technique is a description in code form of what the agent has to do on the node. This code is actually composed of a series of Generic method calls. These different Generic method calls are conditional.

A generic method is a description of an elementary state independent of the operating system (ex: a package is installed, a file contains such line, etc…​). Generic methods are independent of the operating system (It has to work on any operating system). Generic methods calls are conditioned by condition expressions, which are boolean expression combining basic conditions with classic boolean operators (ex : operating system is Debian, such generic method produced a modification, did not produce any modification, produced an error, etc…)

Rudder provides a set of pre-defined Techniques that cover some basic configuration and system administration needs. Of course,this set of techniques cannot responds to all of the specific needs of each client. That’s why Rudder integrate the Technique editor, a tool to create advanced Techniques. Directly accessible from Ruder menu (Configuration policy → Techniques), this tool has an easy-to-use interface, which doesn’t require any programming skills but nevertheless allows to create complex Techniques.

Here is an overview of its interface :

The interface is divided into 3 columns:

Here, we can see our previously created Techniques. We can click on them to see their details/edit them, or create a new one by clicking on the “New” button. Theses Techniques are visible in the ncf techniques category in the Directives tree, so can be used to create new Directives.

When we create a new Technique, or when we edit an existing one, the configuration form appears at the center of the interface, instead of the title and the description of the tool.

Then we can see the name, the description, the Bundle name, the version and the Generic methods list of the current Technique. Only the name and the description are editable, the Bundle name and the version are automatically defined during the Technique creation.

To the right of the interface is the list of Generic methods available for Technique configuration. This list is made up of about a hundred Generic methods, grouped according to their category to make them easier to use (an exhaustive list can be found in the reference documentation)

You just need to click on a Generic method or drag’n drop it in the area provided for such purpose to add it to the current Technique. Once it’s done, you can configure it by clicking on it. Then a new display containing the method details appears instead of the Generic methods list:

The Generic method details are divided into 3 blocks :

Theses conditions can be used in another Generic methods conditions. ie, you can execute a command if a previous one failed or was repaired.

Let’s start from the beginning. Click on the "New Technique" button and start filling in the General information fields (only name is required).

In our case:

Now, we have to find and add the generic methods which correspond to the actions we want to execute. In our case, we want to add the following methods:

And… It’s already done. Rather fast, right? Don’t forget to save. Now you can see it in the Directives tree, and use it to create a Directive that will be applied on your Nodes thanks to a Rule.