Image Capture Sequence

The following diagram shows the how the image capture sequence differs if different provisioning modules are used -- xCAT and VMWare.  Take note of the following:

• The calls made by image.pm to the xCAT and VMWare capture() subroutines areidentical.  image.pm does not care which provisioning engine is being used.  All it knows is that a provisioning engine object has been created before process() was called, the object can be accessed via $self->provisioner, and the name of the subroutine to call is capture().
• The calls made by xCAT and VMWare to the Windows.pm capture_prepare() subroutine areidentical.  All a provisioning engine module needs to know is that an OS object has been created, the object can be accessed via $self->os, and the name of the subroutine to call is pre_image().
• Each provisioning engine module does not need to know any of the operating system details.  They assume the OS module's pre_image() subroutine will perform all the steps necessary for the particular OS to be captured and that the computer will be shut down when pre_image() returns.
• The OS module's pre_capture() subroutine does not care which provisioning engine is being used.  It performs identical steps.
• A very similar example could be made using the same provisioning engine module and different OS modules.