I just wanted to blurt this out since it hit me a few times at the
summit, and see if I'm misreading the rooms.
For the last few years, Nova has pushed back on adding orchestration to
the compute API, and even define a policy for it since it comes up so
much [1]. The stance is that the compute API should expose capabilities
that a higher-level orchestration service can stitch together for a more
fluid end user experience.
One simple example that comes up time and again is allowing a user to
pass volume type to the compute API when booting from volume such that
when nova creates the backing volume in Cinder, it passes through the
volume type. If you need a non-default volume type for boot from volume,
the way you do this today is first create the volume with said type in
Cinder and then provide that volume to the compute API when creating the
server. However, people claim that is bad UX or hard for users to
understand, something like that (at least from a command line, I assume
Horizon hides this, and basic users should probably be using Horizon
anyway right?).
While talking about claims in the scheduler and a top-level conductor
for cells v2 deployments, we've talked about the desire to eliminate
"up-calls" from the compute service to the top-level controller services
(nova-api, nova-conductor and nova-scheduler). Build retries is one such
up-call. CERN disables build retries, but others rely on them, because
of how racy claims in the computes are (that's another story and why
we're working on fixing it). While talking about this, we asked, "why
not just do away with build retries in nova altogether? If the scheduler
picks a host and the build fails, it fails, and you have to
retry/rebuild/delete/recreate from a top-level service."
But during several different Forum sessions, like user API improvements
[2] but also the cells v2 and claims in the scheduler sessions, I was
hearing about how operators only wanted to expose the base IaaS services
and APIs and end API users wanted to only use those, which means any
improvements in those APIs would have to be in the base APIs (nova,
cinder, etc). To me, that generally means any orchestration would have
to be baked into the compute API if you're not using Heat or something
similar.
Am I missing the point, or is the pendulum really swinging away from
PaaS layer services which abstract the dirty details of the lower-level
IaaS APIs? Or was this always something people wanted and I've just
never made the connection until now?
[1] https://docs.openstack.org/developer/nova/project_scope.html#api-scope
[2]
https://etherpad.openstack.org/p/BOS-forum-openstack-user-api-improvements
--
Thanks,
Matt
__________________________________________________________________________
OpenStack Development Mailing List (not for usage questions)
Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
