dhcp agent not discarding stale updates

[Kevin Benton]

The DHCP agent ends up asking for IPs on subnets it already has IPs on because of the following order of events:

neutron_port_create (for DHCP port)
neutron_port_status_update (from l2 agent for dhcp port)
neutron_subnet_create

However, because the dhcp agent uses a semaphore, events may be processed in this order

subnet_create_end (which DHCP agent uses to update dhcp port)
port_update_end (which has the DHCP agent's port from port_status_update and causes the agent to think IPs have changed and retriggers a request to the server)

The issue here is that the agent is recognizing the port update message as stale.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/373566

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/373566
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=9019ff2f744ae91839d05a188358ef92343add43
Submitter: Jenkins
Branch: master

commit 9019ff2f744ae91839d05a188358ef92343add43
Author: Kevin Benton <email address hidden>
Date: Mon Sep 19 18:44:02 2016 -0700

    Make DHCP agent use 'revision_number'

    Change I445974b0e0dabb762807c6f318b1b44f51b3fe15 updated the
    'revision' field to 'revision_number' but it missed the DHCP
    agent and subsequently broke it's ability to detect stale updates.

    This fixes the name in the agent.

    This is marked as a partial for 1622616 because one of the reasons
    the agent was frequently updating the DHCP port was in reaction
    to stale port update messages for its own port.

    Partial-Bug: #1622616
    Closes-Bug: #1625867
    Change-Id: Id41000127e1084f7ff243f8dc9c399999fbdaab4

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/newton
Review: https://review.openstack.org/373887

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/373887
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=c11b08a66887490a4643690bd0a4360a3b0a9215
Submitter: Jenkins
Branch: stable/newton

commit c11b08a66887490a4643690bd0a4360a3b0a9215
Author: Kevin Benton <email address hidden>
Date: Mon Sep 19 18:44:02 2016 -0700

    Make DHCP agent use 'revision_number'

    Change I445974b0e0dabb762807c6f318b1b44f51b3fe15 updated the
    'revision' field to 'revision_number' but it missed the DHCP
    agent and subsequently broke it's ability to detect stale updates.

    This fixes the name in the agent.

    This is marked as a partial for 1622616 because one of the reasons
    the agent was frequently updating the DHCP port was in reaction
    to stale port update messages for its own port.

    Partial-Bug: #1622616
    Closes-Bug: #1625867
    Change-Id: Id41000127e1084f7ff243f8dc9c399999fbdaab4
    (cherry picked from commit 9019ff2f744ae91839d05a188358ef92343add43)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 9.0.0.0rc2 release candidate.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 10.0.0.0b1 development milestone.