-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Andy,
What you have proposed makes sense to me. I vote to go ahead with it. Josh On Thursday February 12, 2009, Andy Kurth 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 will be able to have the computer left in the state it > requires. The default value will be off, meaning the OS will shut the > computer down after its pre_capture() tasks are done. > > 4. OS::capture_start() will be eliminated. All OS capture steps will be > handled by a single subroutine - pre_capture() including the final steps of > calling sysprep.exe if Windows and leaving the computer in the state > described in #3. I don't see a need to separate pre_capture() and > capture_start(). > > 5. Provisioning::capture_monitor() will be eliminated. Control is passed > from image.pm to the provisioning module's capture() subroutine. If > capture() needs to monitor the image being saved, it can either do so > directly in capture() or call another subroutine within the provisioning > module. > > > There are some other pages I started on the Confluence site. They are > somewhat messy at the moment. Feel free to add to them: > > General documentation for modularization: > http://cwiki.apache.org/confluence/display/VCL/Modularized+Architecture > > OS module API specification: > http://cwiki.apache.org/confluence/display/VCL/Operating+System+Module+Inte >rface+Specification > > Provisioning module API specification: > http://cwiki.apache.org/confluence/display/VCL/Provisioning+Engine+Module+I >nterface+Specification > > > Thanks, > Andy - -- - ------------------------------- Josh Thompson Systems Programmer Virtual Computing Lab (VCL) North Carolina State University josh_thomp...@ncsu.edu 919-515-5323 my GPG/PGP key can be found at pgp.mit.edu -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFJlI+TV/LQcNdtPQMRAqg5AJ4gebR0Z9saXj3SDP2Nl17+97cM+ACfeASu IiCvt3ZqmxkRvytu9VeHim8= =yWlX -----END PGP SIGNATURE-----
