nodepool/releasenotes/notes/buildid-4131ffe6f4cea09f.yaml
James E. Blair 3815cce7aa Change image ID from int sequence to UUID
When we export and import image data (for backup/restore purposes),
we need to reset the ZK sequence counter for image builds in order
to avoid collisions.  The only way we can do that is to create and
then delete a large number of znodes.  Some sites (including
OpenDev) have sequence numbers that are in the hundreds of thousands.

To avoid this time-consuming operation (which is only intended to
be run to restore from backup -- when operators are already under
additional stress!), this change switches the build IDs from integer
sequences to UUIDs.  This avoids the problem with collisions after
import (at least, to the degree that UUIDs avoid collisions).

The actual change is fairly simple, but many unit tests need to be
updated.

Since the change is user-visible in the command output (image lists,
etc), a release note is added.

A related change which updates all of the textual references of
build "number" to build "id" follows this one for clarity and ease
of review.

Change-Id: Ie7c68b094bc9733914a808756eeee8b62f696713
2023-08-02 11:18:15 -07:00

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YAML

---
upgrade:
- |
New diskimage build ids are now in UUID format instead of integer
sequences with leading zeroes. This facilitates faster
restoration of images from backup data on systems with large
numbers of image builds. Existing builds will continue to use the
integer format and can coexist with the new format.