Comment 12 for bug 1158684

Reviewed: https://review.openstack.org/121693
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=30ece56a2118bff073e36a108324d12ee646fab6
Submitter: Jenkins
Branch: master

commit 30ece56a2118bff073e36a108324d12ee646fab6
Author: Steve Baker <email address hidden>
Date: Mon Sep 15 16:37:29 2014 +1200

    Default port policy to force replacement

    This change adds a replacement_policy property to OS::Neutron::Port
    which defaults to always replacing the port on stack-update
    regardless of any changes to the template.

    Currently when a server is replaced, the new server is booted with
    the port that is still attached to the old server, which raises a
    port-still-in-use error.

    Even if heat managed to detach and attach a single port, Nova currently
    deletes all ports on interface-detach and server delete, so the port
    would no longer be available anyway.

    This change ensures that a new server is always booted with a new port,
    so it fixes the above 2 issues, however there are implications for
    other scenarios.

    If the server is not replaced during the stack-update, the server
    handle_update will detach/attach to the new port, so this is fine.

    If the port specifies a fixed_ips ip_address which doesn't change
    during stack-update, an error will be raised that 2 ports exist
    with the same IP address. The only current workaround would be
    to set update_policy:AUTO and not make any changes to the server
    which results in server replacement (or do 2 stack updates using
    a transition ip_address).

    Likewise, update_policy:AUTO will need to be set on any port
    consumed by resources which don't support update without replacement
    (such as OS::Neutron::FloatingIP and OS::Trove::Instance)

    Change-Id: I558db6bac196f49e5c488a577f0580c934b06747
    Closes-Bug: #1301486
    Related-Bug: #1158684
    Related-Bug: #1369748