AttributeError when setting external gw in DVR case

[Armando Migliaccio]

This has been found on master:

1) create a DVR router: neutron router-create test --distributed
2) set external gateway: neutron router-gateway-set test public
3) observe stacktrace: http://paste.openstack.org/show/90577/ in L3 Agent's log

This does not seem to upset the L3 Agent and its ability to work correctly, but it would be good to eradicate the trace.

[Carl Baldwin (carl-baldwin)]

Setting to Medium because it is reported that it does not affect the agent's ability to work correctly. Agree with Armando that it should be fixed soon.

Also, tagged low-hanging-fruit.

[Armando Migliaccio (armando-migliaccio)]

Another example of this stracktrace:

http://logs.openstack.org/43/111143/2/experimental/check-tempest-dsvm-neutron-dvr/a4f7648/logs/screen-q-vpn.txt.gz?#_2014-08-01_14_29_55_005

[Armando Migliaccio (armando-migliaccio)]

This is kind of a corner-case where the external gateway is set prior to adding an internal interface to the router. If we follow this workflow instead:

0) Create network/subnet "test"

1) create a DVR router: neutron router-create test --distributed
2) add router interface to subnet: neutron router-interface-add test test
3) set external gateway: neutron router-gateway-set test public

Everything goes smoothly.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/112146

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/112385

[OpenStack Infra (hudson-openstack)]

Change abandoned by Armando Migliaccio (<email address hidden>) on branch: master
Review: https://review.openstack.org/112385

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/112146
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=608003408b3aba6a8290427257460287d8a4ce96
Submitter: Jenkins
Branch: master

commit 608003408b3aba6a8290427257460287d8a4ce96
Author: armando-migliaccio <email address hidden>
Date: Tue Aug 5 12:35:37 2014 -0700

    Fix AttributeError when setting external gateway on DVR router

    DVR routers will have this manager initialized only after one
    or more subnets have been attached to the router. To address
    the issue, make sure the manager is defined and handle the snat
    rules appropriately.

    This patch also makes _update_arp_entry more defensive; this is
    because the arp update process can be affected by the same issue:
    the router may not have internal ports at the time the request
    come in. This is likely when VM's port creation and router
    configuration overlap slightly.

    Closes-bug: #1353006

    Change-Id: Ib46852f5b264e5ef2e2d499d3351f8974e393011
    Co-authored-by: Rajeev Grover <email address hidden>