Re: How to change nova db in Train ?

I can fix it in upstream master and backport it only downstream. I would use 403_placeholder.py in "downstream train" and when the customer upgrades from "downstream stein" to "downstream train", he can get the altered column. Do you think this is feasible ?

Yes, if you make the master migration idempotent (which it should be anyway), then you can effectively just copy it to 403_placeholder.py (replacing the name with something useful) and they will get it when they upgrade, assuming they haven't rolled over 403 yet. When they get to what is now master, the idempotent master equivalent should result in a no-op. --Dan