Open Stack

Over the past few days a few of us have been experimenting with
extracting placement to its own repo, as has been discussed at
length on this list, and in some etherpads:

     https://etherpad.openstack.org/p/placement-extract-stein
     https://etherpad.openstack.org/p/placement-extraction-file-notes

As part of that, I've been doing some exploration to tease out the
issues we're going to hit as we do it. None of this is work that
will be merged, rather it is stuff to figure out what we need to
know to do the eventual merging correctly and efficiently.

Please note that doing that is just the near edge of a large
collection of changes that will cascade in many ways to many
projects, tools, distros, etc. The people doing this are aware of
that, and the relative simplicity (and fairly immediate success) of
these experiments is not misleading people into thinking "hey, no
big deal". It's a big deal.

There's a strategy now (described at the end of the first etherpad
listed above) for trimming the nova history to create a thing which
is placement. From the first run of that Ed created a github repo
and I branched that to eventually create:

     https://github.com/EdLeafe/placement/pull/2

In that, all the placement unit and functional tests are now
passing, and my placecat [1] integration suite also passes.

That work has highlighted some gaps in the process for trimming
history which will be refined to create another interim repo. We'll
repeat this until the process is smooth, eventually resulting in an
openstack/placement.

To take things further, this morning I pip installed the placement
code represented by that pull request into a nova repo and made some
changes to remove placement from nova.

With some minor adjustments I got the remaining unit and functional
tests working.

That work is in gerrit at

     https://review.openstack.org/#/c/596291/

with a hopefully clear commit message about what's going on. As with
the rest of this work, this is not something to merge, rather an
experiment to learn from. The hot spots in the changes are
relatively limited and about what you would expect so, with luck,
should be pretty easy to deal with, some of them even before we
actually do any extracting (to enhance the boundaries between the
two services).

If you're interested in this process please have a look at all the
links and leave comments there, in response to this email, or join
#openstack-placement on freenode to talk about it.

Thanks.

[1] https://github.com/cdent/placecat
-- 
Chris Dent                       ٩◔̯◔۶           https://anticdent.org/
freenode: cdent                                         tw: @anticdent