Don't attach to multiple Quantum networks by default

[Phil Day]

If no networking information is passed to a create request Nova will connect the instance to all available networks.

Whilst this may make sense in Nova Networking (where the networks are mainly controlled by the cloud provider) in a Quantum configuration, where the user may have many networks it really doesn't make sense to allow this, as the network order is non-deterministic and most guest OS's will only set up the first network (which may not be the one which is externally route-able.

To prevent the user getting into this state, the system should reject requests with no networking information when more than one quantum network is available, so that the user is made to specify them in the required order.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/33996

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/33996
Committed: http://github.com/openstack/nova/commit/5936b2158da16bc0dbcaa99d5009a76f077999d7
Submitter: Jenkins
Branch: master

commit 5936b2158da16bc0dbcaa99d5009a76f077999d7
Author: Phil Day <email address hidden>
Date: Fri Jun 21 15:57:31 2013 +0100

    Don't attach to multiple Quantum networks by default

    If no networking information is passed to a create request
    Nova will connect the instance to all available networks.

    In a Quantum configuration, where the user may have many
    networks it really doesn't make sense to allow this, as the
    network order is critical to most Guests and this approach
    non-deterministic.

    For example most guest OS's will only automatically configure
    the first network which may not be externally route-able thereby
    leaving the instance in an un-usable state.

    To prevent the user getting into this state, the system should
    reject requests with no networking information when more than
    one quantum network is available, so that the user is made to
    specify them in the required order.

    Fixes bug 1193376

    Change-Id: I950798cc3d04994b82be16e94397c117aaceecce