Comment 7 for bug 1766301

Reviewed: https://review.opendev.org/743493
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=6be5a27b361ebaa36975459a2a32bf4330ce2660
Submitter: Zuul
Branch: stable/queens

commit 6be5a27b361ebaa36975459a2a32bf4330ce2660
Author: Jim Rollenhagen <email address hidden>
Date: Mon Apr 23 13:53:00 2018 -0400

    ironic: add instance_uuid before any other spawn activity

    In the baremetal use case, it is necessary to allow a remote
    source of truth assert information about a physical node,
    as opposed to a client asserting desired configuration.

    As such, the prepare_networks_before_block_device_mapping virt
    driver method was added, however in doing so network VIF attaching
    was moved before actual hardware reservation. As ironic only
    supports users to have a number of VIFs limited by the number
    of network interfaces in the physical node, VIF attach actions
    cannot be performed without first asserting control over the node.

    Adding an "instance_uuid" upfront allows other ironic API consumers
    to be aware that a node is now in use. Alternatively it also allows
    nova to become aware prior to adding network information on the node
    that the node may already be in use by an external user.

    Co-Authored-By: Julia Kreger <email address hidden>

    Conflicts:
        nova/tests/unit/compute/test_compute_mgr.py

    NOTE(melwitt): The conflict is because change
    I755b6fdddc9d754326cd9c81b6880581641f73e8 is not in Queens.

    Closes-Bug: #1766301
    Change-Id: I87f085589bb663c519650f307f25d087c88bbdb1
    (cherry picked from commit e45c5ec819cfba3a45367bfe7dd853769c80d816)