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Placement Update 19-31

Pupdate 19-31. No bromides today.

Most Important

Same as last week: The main things on the Placement radar are implementing Consumer Types and cleanups, performance analysis, and documentation related to nested resource providers.

We need to decide how much of a priority consumer types support is. I've taken the task of asking around with the various interested parties.

What's Changed

  • A more complex nested topology is now being used in the nested-perfload check job, and both that and the non-nest perfload run apache benchmark at the end. When you make changes you can have a look at the results of the placement-perfload and placement-nested-perfload gate jobs to see if there has been a performance impact. Keep in mind the numbers are only a guide. The performance characteristics of VMs from different CI providers varies wildly.

  • A stack of several performance related improvements has merged, with still more to come. I've written a separate Placement Performance Analysis that summarizes some of the changes. Many of these may be useful for other services. Each iteration reveals another opportunity.

  • In some environments placement will receive a URL of '' when '/' is expected. Auth handling for version control needs to handle this.

  • osc-placmeent 1.6.0 is in the process of being released.


(Numbers in () are the change since the last pupdate.)

There are 22 (-1) stories in the placement group. 0 (0) are untagged. 3 (0) are bugs. 4 (-1) are cleanups. 11 (0) are rfes. 4 (0) are docs.

If you're interested in helping out with placement, those stories are good places to look.


osc-placement is currently behind by 12 microversions.

  • Add support for multiple member_of. There's been some useful discussion about how to achieve this, and a consensus has emerged on how to get the best results.

  • Adds a new '--amend' option which can update resource provider inventory without requiring the user to pass a full replacement for inventory. This has been broken up into three patches to help with review.

Main Themes

Consumer Types

Adding a type to consumers will allow them to be grouped for various purposes, including quota accounting.


Cleanup is an overarching theme related to improving documentation, performance and the maintainability of the code. The changes we are making this cycle are fairly complex to use and are fairly complex to write, so it is good that we're going to have plenty of time to clean and clarify all these things.

As said above, there's lots of performance work in progress. We'll need to make a similar effort with regard to docs.

One outcome of this work will be something like a Deployment Considerations document to help people choose how to tweak their placement deployment to match their needs. The simple answer is use more web servers and more database servers, but that's often very wasteful.

Other Placement

Miscellaneous changes can be found in the usual place.

There are two os-traits changes being discussed. And zero os-resource-classes changes.

Other Service Users

New discoveries are added to the end. Merged stuff is removed. Anything that has had no activity in 4 weeks has been removed.


Somewhere in this performance work is a lesson for life: Every time I think we've reached the bottom of the "easy stuff", I find yet another bit of easy stuff.

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