ML2 plugin deletes port even if associated with multiple subnets on subnet deletion

[Oleg Bondarev]

On subnet deletion ml2 plugin deletes all the ports associated with this subnet and does not check if a port is associated with other subnets.
Steps to reproduce:
1) create a network with two subnets
2) create dhcp port for the network, port is associated with both subnets
3) delete one of the subnets
4) dhcp port is getting deleted

Though new dhcp port is created shortly I think it's not ok to delete existing dhcp port.

[Robert Kukura (rkukura)]

In NeutronDbPluginV2.delete_subnet(), there is a statement "allocated.delete()" that I had erroneously interpreted as deleting the port at the DB level - probably mislead by the "# remove network owned ports" comment. I therefore changed Ml2Plugin.delete_subnet() to not call the base class and to instead use its own delete_port() method so that MechanismDrivers would be called for the auto-deleted port.

But, as Oleg discovered, the base class's "allocated.delete()" statement is actually just deleting the IPAllocation record, not the port itself. This is in effect removing the subnet's IP from the port's fixed_ips attribute. Therefore, instead of calling delete_port(), the Ml2Plugin.delete_subnet() method should be calling update_port() for each allocation to remove the IP from the port and call the MechanismDrivers.

[Armando Migliaccio (armando-migliaccio)]

This review might be relevant to this bug: https://review.openstack.org/#/c/54850/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/54918

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/54918
Committed: http://github.com/openstack/neutron/commit/0d131ff0e9964cb6a65f64809270f9d597c2d5d1
Submitter: Jenkins
Branch: master

commit 0d131ff0e9964cb6a65f64809270f9d597c2d5d1
Author: Oleg Bondarev <email address hidden>
Date: Fri Nov 1 15:20:27 2013 +0400

    ML2 plugin should not delete ports on subnet deletion

    On subnet deletion ports are deleted asynchronously by dhcp agent
    so plugin doesn't need to delete them itself.
    Instead Ml2Plugin.delete_subnet() method should call update_port()
    for each allocation to remove the IP from the port and call the MechanismDrivers.
    The patch also adds subnets test suite from test_db_plugin to test_ml2_plugin.

    Closes-Bug: #1246737
    Change-Id: I7cf0461e9a3cfec4921e2de41fb1ab3fc119fddc

[Armando Migliaccio (armando-migliaccio)]

This has been reverted here:

https://review.openstack.org/#/c/58827/

Because of a side-effect that might have been introduced by this one.

Please take the time to look at this one again to ensure the right behavior is implemented at subnet deletion

[Akihiro Motoki (amotoki)]

If I understand correctly, there is no patch commited in stable/havana.

[Akihiro Motoki (amotoki)]

I confirmed the issue still exists in stable/havana.

[Alan Pevec (apevec)]

Sorry for the confusion, script set this to commited on stable/havana based on this bug# mentioned in https://github.com/openstack/neutron/commit/35e595f7b3d85eb6053a50ab08044bd89eb554ab

[Shiv Haris (shh)]

Oleg, can u please update what more needs to be done here. it says backport to Havana. really? anyone affected by this?

[padkrish (kprad1)]

Just for records, this currently seems to be committed. I was slightly misled, thinking it's reverted by https://review.openstack.org/#/c/58827/ !!

https://review.openstack.org/#/c/62696/

https://github.com/openstack/neutron/commit/58cc80a2a883a13120eadd487b55b5c3b683b5b6

[padkrish (kprad1)]

We had a discussion today in the ML2 IRC. Does it really need to be back ported to havana? If not, this can be closed. I have modified the status to "Opinion"

[Andrey Epifanov (aepifanov)]

This bug was fixed with with the following commit:
https://review.openstack.org/#/c/62696/

[Itsuro Oda (oda-g)]

icehouse was released with this patch reverted. Should be re-submitted to icehouse too.