DC subcloud with admin network failed to install, due to multiple default gateway configurations

[Lucas Ratusznei Fonseca]

Brief Description
-----------------
DC subcloud installed with admin network failed to come up after first unlock during a runtime manifest to configure the admin network.
The problem is caused by sysinv generating a default gateway configuration for each interface associated with an address-pool that contains the gateway address set. Since there can be only one default gateway address in the system, it created the problem.

Severity
--------
Critial.

Steps to Reproduce
------------------
Install a DC and a subcloud with the default admin network.

Expected Behavior
------------------
Default gateway is the OAM gateway.

Actual Behavior
----------------
Default gateway is the Admin gateway.

Reproducibility
---------------
100% reproducible.

System Configuration
--------------------
DC with AIO-SX subcloud.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/config/+/919618

[Ghada Khalil (gkhalil)]

Issue introduced by IPv4/IPv6 dual stack support: https://storyboard.openstack.org/#!/story/2011027

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/config/+/919618
Committed: https://opendev.org/starlingx/config/commit/136eecd2349ad3ea5d4f939dece4203ba3347030
Submitter: "Zuul (22348)"
Branch: master

commit 136eecd2349ad3ea5d4f939dece4203ba3347030
Author: Lucas Ratusznei Fonseca <email address hidden>
Date: Tue May 14 15:07:31 2024 -0300

    Generate network interface config with single default gateway

    As it was before, sysinv placed a gateway address in every interface
    config file for which the corresponding address pool had a gateway
    specified. This allowed multiple default gateways to exist
    simultaneously in the system, causing network problems.
    This change improves the hieradata generation logic so that only one
    interface has default gateways, one for each address family. The
    chosen interface config follows a precedence order which depends on
    the network type: OAM > Management > Admin.

    Test plan

    System: AIO-SX subcloud IPv4

    Initial setup:
      - oam0: ethernet, assigned to oam network, with gateway address
      - mgmt0: ethernet, assigned to mgmt network, no gateway address
      - admin0: ethernet, assigned to admin network, no gateway address

    [PASS] Add gateway to mgmt's address pool, check that oam's gateway
           remains the default
    [PASS] Add gateway to admin's address pool, check that oam's gateway
           remains the default
    [PASS] Remove gateway from oam's address pool, check that mgmt's
           gateway becomes the default
    [PASS] Remove gateway from mgmt's address pool, check that admin's
           gateway becomes the default

    Closes-Bug: 2065715
    Change-Id: I28eb5de0c34db2cef089c83cf568ba61fa2d4e42
    Signed-off-by: Lucas Ratusznei Fonseca <email address hidden>