openvswitch plugin would fail with replicated quantum-server

[Robert Kukura]

OpenStack API services can generally be replicated behind a load balancer in order to scale horizontally, or an SSL terminator might dispatch requests to multiple server processes in parallel. In either case, multiple quantum-server processes might execute in parallel using the same DB. The openvswitch plugin currently maintains a VlanMap class in memory that is used to keep track of free VLAN tags and allocate them as networks are created. If multiple quantum-server instances run in parallel, its possible that the openvswitch plugin would allocate the same VLAN tag to multiple networks, breaking network isolation as well as database consistency. VLAN tags should instead be allocated via atomic DB transactions.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/10700

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/10700
Committed: http://github.com/openstack/quantum/commit/88078250028d50b6d726a6bdf79874a2f4e9abce
Submitter: Jenkins
Branch: master

commit 88078250028d50b6d726a6bdf79874a2f4e9abce
Author: Bob Kukura <email address hidden>
Date: Mon Jul 30 14:52:06 2012 -0400

    Replace openvswitch plugin's VlanMap with vlan_ids DB table.

    Fixes bug 1023167.

    The openswitch plugin's in-memory VlanMap is replaced with a vlan_ids
    DB table similar to that used by the linuxbridge plugin. This will
    prevent conflicting VLAN assignments if multiple server replicas are
    run, and also sets the stage for phase 2 of the provider-networks BP
    implementation that will add support for multiple physical
    networks.

    Unlike with the current linuxbridge plugin, the contents of the
    openvswitch plugin's vlan_ids table are properly updated at startup in
    case the vlan_min or vlan_max configuration variables have changed.

    A new test_ovs_db test case has been added.

    The primary key of the vlan_bindings table is changed from the vlan_id
    to the network_id, which is now a foreign key, and network deletion is
    now properly handled.

    The net_id has been removed from the VlanIdInUse exception, requiring
    a minor update to the linuxbridge plugin. The new NoNetworksAvailable
    exception, with ResourceExhausted as its base class, is returned when
    no more VLANs are available.

    Change-Id: I65a2347dea5366cc0d15d98a88f40e42e1a45f4c