[Engine-devel] [virt-node] VDSM as a general purpose virt host manager

[Saggi Mizrahi]

There is an important discussion starting about the future of the VDSM API on
vdsm-devel. If you want to be involved in the future of the VDSM API don't miss
out and join vdsm-devel. To sign up go to
https://fedorahosted.org/mailman/listinfo/vdsm-devel

There growing need for a way to more easily reuse of the functionality of VDSM
in order to service projects other than Ovirt-Engine.

Originally VDSM was created as a proprietary agent for the sole purpose of
serving the then proprietary version of what is known as ovirt-engine. Red Hat,
after acquiring the technology, pressed on with it's commitment to open source
ideals and released the code. But just releasing code into the wild doesn't
build a community or makes a project successful. Further more when building
open source software you should aspire to build reusable components instead of
monolithic stacks.

We would like to expose a stable, documented, well supported API. This gives
us a chance to rethink the VDSM API from the ground up. There is already work
in progress of making the internal logic of VDSM separate enough from the API
layer so we could continue feature development and bug fixing while designing
the API of the future.

In order to achieve this though we need to do several things:
   1. Declare API supportability guidelines
   2. Decide on an API transport (e.g. REST, ZMQ, AMQP)
   3. Make the API easily consumable (e.g. proper docs, example code, extending
      the API, etc)
   4. Implement the API itself

All of these are dependent on one another and the permutations are endless.
This is why I think we should try and work on each one separately. All
discussions will be done openly on the mailing list and until the final version
comes out nothing is set in stone.

If you think you have anything to contribute to this process, please do so
either by commenting on the discussions or by sending code/docs/whatever
patches. Once the API solidifies it will be quite difficult to change
fundamental things, so speak now or forever hold your peace. Note that this is
just an introductory email. There will be a quick follow up email to kick start
the discussions. Don't forget to sign up to the vdsm-devel mailing list.