Open Stack

On Wed, Sep 26, 2018 at 3:44 PM, Matt Riedemann <mriedemos at gmail.com> wrote:
> I started documenting the compute API gaps in OSC last release [1]. It's a
> big gap and needs a lot of work, even for existing CLIs (the cold/live
> migration CLIs in OSC are a mess, and you can't even boot from volume where
> nova creates the volume for you). That's also why I put something into the
> etherpad about the OSC core team even being able to handle an onslaught of
> changes for a goal like this.

The OSC core team is very thin, yes, it seems as though companies
don't like to spend money on client-facing things...I'll be in the
hall following this thread should anyone want to talk...

The migration commands are a mess, mostly because I got them wrong to
start with and we have only tried to patch it up, this is one area I
think we need to wipe clean and fix properly.  Yay! Major version
release!

> I thought the same, and we talked about this at the Austin summit, but OSC
> is inconsistent about this (you can live migrate a server but you can't
> evacuate it - there is no CLI for evacuation). It also came up at the Stein
> PTG with Dean in the nova room giving us some direction. [2] I believe the
> summary of that discussion was:

> a) to deal with the core team sprawl, we could move the compute stuff out of
> python-openstackclient and into an osc-compute plugin (like the
> osc-placement plugin for the placement service); then we could create a new
> core team which would have python-openstackclient-core as a superset

This is not my first choice but is not terrible either...

> b) Dean suggested that we close the compute API gaps in the SDK first, but
> that could take a long time as well...but it sounded like we could use the
> SDK for things that existed in the SDK and use novaclient for things that
> didn't yet exist in the SDK

Yup, this can be done in parallel.  The unit of decision for use sdk
vs use XXXclient lib is per-API call.  If the client lib can use an
SDK adapter/session it becomes even better.  I think the priority for
what to address first should be guided by complete gaps in coverage
and the need for microversion-driven changes.

> This might be a candidate for one of these multi-release goals that the TC
> started talking about at the Stein PTG. I could see something like this
> being a goal for Stein:
>
> "Each project owns its own osc-<service_type> plugin for OSC CLIs"
>
> That deals with the core team and sprawl issue, especially with stevemar
> being gone and dtroyer being distracted by shiny x-men bird related things.
> That also seems relatively manageable for all projects to do in a single
> release. Having a single-release goal of "close all gaps across all service
> types" is going to be extremely tough for any older projects that had CLIs
> before OSC was created (nova/cinder/glance/keystone). For newer projects,
> like placement, it's not a problem because they never created any other CLI
> outside of OSC.

I think the major difficulty here is simply how to migrate users from
today state to future state in a reasonable manner.  If we could teach
OSC how to handle the same command being defined in multiple plugins
properly (hello entrypoints!) it could be much simpler as we could
start creating the new plugins and switch as the new command
implementations become available rather than having a hard cutover.

Or maybe the definition of OSC v4 is as above and we just work at it
until complete and cut over at the end.  Note that the current APIs
that are in-repo (Compute, Identity, Image, Network, Object, Volume)
are all implemented using the plugin structure, OSC v4 could start as
the breaking out of those without command changes (except new
migration commands!) and then the plugins all re-write and update at
their own tempo.  Dang, did I just deconstruct my project?

One thing I don't like about that is we just replace N client libs
with N (or more) plugins now and the number of things a user must
install doesn't go down.  I would like to hear from anyone who deals
with installing OSC if that is still a big deal or should I let go of
that worry?

dt

-- 

Dean Troyer
dtroyer at gmail.com