Open Stack

Thanks for this, a few things inline.

On 6/15/2018 10:04 AM, Chris Dent wrote:
> 
> The flip side of this is that it highlights that we have a growing
> documentation debt with the many features provided by placement and
> how to make best use of them in nova (and other services that might
> like to use placement). Before the end of the cycle we will need to
> be sure that we set aside a considerable chunk of time to address
> this gap.

I'm glad you mentioned this so I didn't have to. :) The two things off 
the top of my head that are going to be important for docs are:

1. How to deploy / model shared disk. Seems fairly straight-forward, and 
we could even maybe create a multi-node ceph job that does this - 
wouldn't that be awesome?!?!

2. Adding the placement database stuff to the install guide and the 
placement upgrade notes. I assume that for fresh installs, we want 
people using the placement database configuration so they don't have to 
move later during an upgrade, so that seems like a no-brainer. The 
upgrade docs for placement are per-release and should have a mention of 
the placement database and any notes / pointers (the spec?) on migration 
options. What we heard at the summit, for the most part, was 10 minutes 
of down time in the API for a DB copy and re-config was OK for most, and 
others that need zero downtime have ways of doing that as well. We don't 
need a definitive guide, just high level wording on options.

> 
> There is now a [heal allocations
> CLI](https://review.openstack.org/#/c/565886/) which is designed to
> help people migrate away from the CachingScheduler (which doesn't
> use placement).

Not only that, but we can use it to heal missing/sentinel consumers from 
the "consumer generations" blueprint. I've started something for that here:

https://review.openstack.org/#/c/574488/

> 
> Nova host aggregates are now magically mirrored as placement
> aggregates and, amongst other things, this is used to honor the
> [availability_zone hint via
> placement](https://review.openstack.org/#/c/546282/).

The aggregates mirror blueprint is not done until the 'nova-manage 
placement sync_aggregates' command is in place, which is started here:

https://review.openstack.org/#/c/575912/

> 
> # Extraction
> 

All of the functional changes for the placement DB stuff are merged or 
approved, I think there are just some cleanup follow-ups and docs needed 
still, but otherwise that's done I think and could probably be removed 
from the runway slot it's in?

> 
> * <https://review.openstack.org/#/c/538498/>
>    Convert driver supported capabilities to compute node provider
>    traits

I (finally) got around to rebasing this yesterday. There are a few TODOs 
left but it shouldn't be too bad, hopefully I can close that out when I 
get back next week.

-- 

Thanks,

Matt