Dependencies via meta declaration

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The SDM framework does not allow the usage of declaration of dependencies within the meta main file of a role. The reason for this is that task files of a role are comparable to procedures or functions in programming languages and a role can access this role tasks at any time. This access mechanism is equal in horizontal and vertical direction. The following conceivable scenarios explains this mechanism on the basis of the creation of an installation image of an operation system distribution and its derivate.

Scenario 1

A derivate of an operation system distribution uses the same installation image like the parent operation system distribution. The tasks for creating the installation image can executed directly.

Scenario 2

An operation system distribution provides tasks to start and finalise an installation image. A derivate of this operation system distribution uses these tasks to modify the installation image of the parent operation system distribution with its own features. This is done between the executions of the mentioned tasks.

Scenario 3

A derivate of an operation system distribution uses a completely different installation image as the parent operation system distribution. In this case, it is not necessary to execute the tasks of the parent operation system distribution.