The commits I made on 2/26 extended the state modules with the new flow
described in this thread. Up to this point, nothing has functionally changed
because none of the provisioning or OS modules have been committed which have
been modified to use the new flow.
The image capture flow changes and OS modularization that I'm working on are
very intertwined. Vista.pm was the first attempt at modularization and the next
step is to get the other Windows OS's working in the same fashion. I want to
take steps so the code that's already working isn't affected. Here's how I
intend to do this...
See the diagram at the top of this page:
http://cwiki.apache.org/confluence/display/VCL/Operating%20System%20Module%20Inheritance
The current Windows OS modules are using or inheriting from Windows.pm,
Desktop.pm, and Vista.pm. I don't want to change these at all. I plan to
commit new files named Windows_mod.pm, Version_5.pm, Version_6.pm, XP_mod.pm,
and Vista_mod.pm, as shown on the right side of the diagram. This will allow us
to work on and test the new modules without affecting existing, working code.
Once tested and everyone's comfortable with the modularized code, the old files
can be removed and Windows_mod.pm will be renamed Windows.pm, etc. Much of the
code is not actually new. Several subroutines were copied from Vista.pm because
they work for any Windows OS.
It's possible to use the old code and test new in parallel because of the way
the database was designed to handle modularization. All that needs to be done
is to create a new entry in the OS table (call it XP_mod) and a corresponding
entry in the module table with its module.perlpackage column pointing to
XP_mod.pm. Any images you configure with the image.OSid pointing to the new
XP_mod OS type will receive the new code. All of existing XP images will not be
affected. I have begun to document this on the page noted above.
The file named Version_5.pm and Version_6.pm will replace Desktop.pm and
Server.pm (which doesn't actually exist). After working with the different
Windows versions and seeing where the major differences lie, it makes more sense
to organize the Windows inheritance tree by Windows major version rather than
desktop/server.
I have a good bit of the new layout done and will commit it soon if there are no
objections. Please let me know if you have any questions, ideas, or want to help.
Thanks,
Andy
Andy Kurth wrote:
Thanks to everyone for the feedback. I'll begin working on the proposed
changes today.
Thanks,
Andy
Aaron Peeler wrote:
I like these changes also, this falls in line with our overall
modularization goal.
Aaron
--On February 12, 2009 3:48:30 PM -0500 Andy Kurth
andy_ku...@ncsu.edu wrote:
I would like to begin defining and documenting the API for the backend
code as people are actively working on developing new modules. I have
begun some pages on the Confluence site and would like to start
discussing this.
API development is somewhat related to the image capture and
modularization issues discussed at the meeting on 2/5. Solving the
issues requires the modularization architecture to be modified and the
API should be specified/updated along the way.
The main problem is that xCAT.pm expects the OS to reboot when the OS
capture tasks are done and vmware.pm needs the OS to shut down. xCAT.pm
is currently the only provisioning module which has had the OS-specific
code removed and is fully modularized. vmware.pm still contains OS
code.
It will be difficult to modularize vmware.pm and the ESX.pm module that
Brian and Andrew are working on because of this.
I have given it some thought and would like to propose the numbered
changes below. These changes probably sound bigger than they really
are.
Minor changes would need to be made to xCAT.pm and image.pm. This will
be easier to understand if you look at the diagram on the following
page:
http://cwiki.apache.org/confluence/display/VCL/Image+Capture+Sequence
1. The name of the OS module's capture_prepare subroutine will be
changed
to pre_capture(). The reason for this is to align the name of the main
OS capture subroutine with the main OS load subroutine - pre_capture()
and post_load().
2. image.pm will no longer call the OS::pre_capture() subroutine. It
will be the provisioning module's responsibility to do this. This
allows
the provisioning module to have greater control over the capture
sequence. image.pm will only call the provisioning module's capture()
subroutine. This makes better sense to me because provisioning engines
can be quite varied and the sequence should really be driven by the
provisioning module.
3. OS::pre_capture() will accept an optional argument named 'end_state'
with possible values 'on', 'off', 'reboot'. This instructs
OS::pre_capture() what to do after completing its image capture steps.
Because pre_capture() will be called by the provisioning module, the
provisioning module
