Comment 2 for bug 1780373

First, I assume your boot request included the instance group, for example:

  nova boot --flavor flavor --net net-name=netname --image image --max-count 3 --hint group=<sg uuid> server-name

I was able to reproduce this with devstack by setting quota to 2 and using the above command ^ and found the reason for the bug is that the resource count for server_group_members during the quota check counts instance records for a user, and we're not creating instance records until much later on, in conductor. So on a fresh install and a multi-create request, the quota check repeatedly counts 0 group members for a user as we add members to the instance_group_members table in the API database.

I added several comments on the patch review, but to summarize, it seems like we need to consider counting build requests in addition to instance records for multi-create scenarios (and maybe more) while de-duping instance uuids for the small window where a build request and instance record can co-exist for the same instance uuid, to avoid over-counting.