Comment 23 for bug 1981113

Reviewed: https://review.opendev.org/c/openstack/neutron/+/870474
Committed: https://opendev.org/openstack/neutron/commit/bbaca0c86b3cb12aa3414a5e2921f86a8d01de7f
Submitter: "Zuul (22348)"
Branch: stable/zed

commit bbaca0c86b3cb12aa3414a5e2921f86a8d01de7f
Author: Miro Tomaska <email address hidden>
Date: Wed Oct 12 08:42:18 2022 -0500

    Improve agent provision performance for large networks

    Before this patch, the metadata agent would provision network namespace
    for all subnets under a network(datapath) as soon as the first
    VM(vif port) was mounted on the chassis. This operation can take very
    long time for networks with lots of subnets. See the linked bug for
    more details.
    This patch changes this mechanism to "lazy load" where metadata agent
    provisions metadata namespace with only the subnets belonging to the
    active ports on the chassis. This results in virtually constant
    throughput not effected by the number of subnets.

    Merge Conflict:
            Implicitly removes now dead function
            ensure_all_networks_provisioned
            neutron/agent/ovn/metadata/agent.py

    Closes-Bug: #1981113
    Change-Id: Ia2a66cfd3fd1380c5204109742d44f09160548d2
    (cherry picked from commit edf3b3f191c2eae229a754dcbfc448fa41bd8bc3)