dhcp agent shouldn't spawn metadata-proxy for non-isolated networks

[John Schwarz]

The "enable_isolated_metadata = True" options tells DHCP agents that for each network under its care, a neutron-ns-metadata-proxy process should be spawned, regardless if it's isolated or not.
This is fine for isolated networks (networks with no routers and no default gateways), but for networks which are connected to a router (for which the L3 agent spawns a separate neutron-ns-metadata-proxy which is attached to the router's namespace), 2 different metadata proxies are spawned. For these networks, the static routes which are pushed to each instance, letting it know where to search for the metadata-proxy, is not pushed and the proxy spawned from the DHCP agent is left unused.

The DHCP agent should know if the network it handles is isolated or not, and for non-isolated networks, no neutron-ns-metadata-proxy processes should spawn.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/116832

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/116832
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=9569b2fe58d0e836071992f545886ca985d5ace8
Submitter: Jenkins
Branch: master

commit 9569b2fe58d0e836071992f545886ca985d5ace8
Author: John Schwarz <email address hidden>
Date: Tue Aug 26 11:43:11 2014 +0300

    Don't spawn metadata-proxy for non-isolated nets

    If the configuation option "enable_isolated_metadata = True" for the
    DHCP agent is set, the neutron-ns-metadata-proxy process is spawned
    for all networks, regardless if they are isolated or not. In case
    the network is not isolated (ie. connected to a neutron router), the
    L3 agent also spawns a proxy process, and the DHCP's proxy is left
    unused. This patch adds a check prior to the spawning of new proxies:
    if a network is not isolated, no proxy is spawned.

    Change-Id: I9bdb8c3d37997b22435bca33ec47a67db08efa51
    Closes-bug: #1361545

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/icehouse
Review: https://review.openstack.org/123074

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/123074
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=645f9849b6ccf2653ec68e54cf793453af34fe6a
Submitter: Jenkins
Branch: stable/icehouse

commit 645f9849b6ccf2653ec68e54cf793453af34fe6a
Author: John Schwarz <email address hidden>
Date: Tue Aug 26 11:43:11 2014 +0300

    Don't spawn metadata-proxy for non-isolated nets

    If the configuation option "enable_isolated_metadata = True" for the
    DHCP agent is set, the neutron-ns-metadata-proxy process is spawned
    for all networks, regardless if they are isolated or not. In case
    the network is not isolated (ie. connected to a neutron router), the
    L3 agent also spawns a proxy process, and the DHCP's proxy is left
    unused. This patch adds a check prior to the spawning of new proxies:
    if a network is not isolated, no proxy is spawned.

    Conflicts:
     neutron/tests/unit/test_dhcp_agent.py

    Change-Id: I9bdb8c3d37997b22435bca33ec47a67db08efa51
    Closes-bug: #1361545
    (cherry picked from commit 9569b2fe58d0e836071992f545886ca985d5ace8)