Comment 6 for bug 1424096

Reviewed: https://review.openstack.org/176612
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=036133f932dd86f8d34d1e99c8ad2d25db44bd07
Submitter: Jenkins
Branch: stable/juno

commit 036133f932dd86f8d34d1e99c8ad2d25db44bd07
Author: Stephen Ma <email address hidden>
Date: Tue Feb 24 23:31:33 2015 +0000

    Router is not unscheduled when the last port is deleted

    When checking for ports that are still in use on a DVR router,
    the L3 agent scheduler makes the assumption that a port's
    network must be owned by the same tenant. This isn't always
    true as the admin could have created a shared network that
    other tenants may use. The result of this assumption is that
    the router associated with the shared network may not be
    unscheduled from a VM host when the last VM (created by a
    non-admin tenant) using the shared network is deleted from
    the compute node.

    The owner of a VM may not own all the ports of a shared
    network. Other tenants may have VMs using the same shared
    network running on the same compute node. Also the VM owner
    may not own the router ports. In order to check whether a
    router can be unscheduled from a node has to be run with
    admin context so all the ports associated with router are
    returned from database queries.

    This patch fixes this problem by using the admin context to
    make the queries needed for the DVR scheduler to make the
    correct unschedule decision.

    (cherry picked from commit edbade486102a219810137d1c6b916e87475d477)

    Conflicts:
        neutron/db/l3_dvrscheduler_db.py

    Closes-bug: #1424096
    Change-Id: I45477713d7ce16f2451fa6fbe04c610388b06867