maas-devel team mailing list archive

[Graham Binns <graham.binns@xxxxxxxxxxxxx>]

Hi all,

Now that the sprint's past, we can finish the removal of
bootresources.yaml (see previous thread on this list on that topic).

I've been looking at how to replace it with a simple RPC-mesh API for
the cluster to call, thus:

 1. cluster bootstraps
 2. User commands cluster to import images (via UI, CLI, etc.)
 3. m-i-p-f runs on cluster, requests config from region
 4. … time passes … things download …
 5. … all proceeds as before [first iteration]

Now, in this admittedly simple first iteration we're shifting the
knowledge of the boot resources from bootresources.yaml to the DB. We
already have models for BootSource and BootSelection in the database;
it's now a matter of putting a simple API in place and then hooking
things up.

The simplest API I can think of looks like this:

  def get_boot_sources_for_cluster(uuid):
      # Fetch sources for cluster from DB
      # Convert to the same format as returned by a parsed bootresources.yaml
      # Return

This doesn't provide *anything* other than a replacement for the
config file. There's some obvious failure states we need to deal with:

 1. Region isn't up
 2. Region doesn't recognise cluster as one of its own.
 3. No boot sources for the cluster.

My feeling for 3 is that right now we should just set a sane default
for the boot source and then download the world, per Mark's
preferences.

I've doubtless missed something with my simple-minded API above, so
please tell me when you notice something.

I've started putting a branch together for the simple API; you can
find it here: lp:~gmb/maas/boot-source-api

Cheers,

Graham