yahoo-eng-team team mailing list archive

[Bug 2104160] [NEW] [DB] Stop expand migrations with field drop exceptions

Public bug reported:

I'm raising this bug in relationship to [1]. An environment upgrade from
Yoga to Zed caused a dataplane disruption because the L3 agent stopped
working. That was caused by an RPC call to the Neutron API, that
returned an exception.

The problem was caused by [2], that is dropping a table field in an
expand migration. Although we have allowed this kind of exceptions, that
could lead to problems during the upgrades.

The steps to upgrade an environment are (just a small snippet and just related to Neutron):
* Run the DB migration scripts, only the expand ones.
* Upgrade the Neutron APIs.
* Run the DB migration scripts, only the contract ones.

Between the 1st and the 2nd steps, the Neutron API made a call using a
DB schema that no longer exists, raising the exception reported in the
mail chain [3].

The aim of this bug is to stop doing these operations in the DB expand
scripts, documenting it.

[1]https://lists.openstack.org/archives/list/openstack-discuss@xxxxxxxxxxxxxxxxxxx/thread/Y3SHX2BXF5N37465KDYRAXEP4B3UMGQS/
[2]https://review.opendev.org/c/openstack/neutron/+/798961/35/neutron/db/migration/alembic_migrations/versions/zed/expand/I43e0b669096_port_forwarding_port_ranges.py#130
[3]https://paste.openstack.org/show/bJAP7rgEXoFH76wC6zSj/

** Affects: neutron
Importance: Undecided
Status: New

--
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to neutron.
https://bugs.launchpad.net/bugs/2104160

Title:
[DB] Stop expand migrations with field drop exceptions

Status in neutron:
New

Bug description:
I'm raising this bug in relationship to [1]. An environment upgrade
from Yoga to Zed caused a dataplane disruption because the L3 agent
stopped working. That was caused by an RPC call to the Neutron API,
that returned an exception.

The problem was caused by [2], that is dropping a table field in an
expand migration. Although we have allowed this kind of exceptions,
that could lead to problems during the upgrades.

Between the 1st and the 2nd steps, the Neutron API made a call using a
DB schema that no longer exists, raising the exception reported in the
mail chain [3].

The aim of this bug is to stop doing these operations in the DB expand
scripts, documenting it.

To manage notifications about this bug go to:
https://bugs.launchpad.net/neutron/+bug/2104160/+subscriptions