AIO-SX not going enabled when oam interface is down

[Bin Qian]

SM requires at least 1 interface (oam, mgmt or infra) to be in "up" state before starting scheduling service, this is correct as SM needs to communicate to the peer to determine the role it is. This is not true for AIO-SX, as it is designed to not having peers, so it shouldn't wait for interface to be in "up" state.

This bug causes an AIO-SX not being enabled if oam interface is down.

Severity
--------
This is critical as it causes unexpected system out of service

Step to reporduce
--------
Configure an AIO-SX, unplug the oam cable and reboot the node. When the node is up, the node will not be enabled until the oam cable plug in.

Expected Behavior
--------
The system should be enabled, and an alarm should be raise for oam is down.

Reproducibility
--------
Reproducible

System configuration
--------
Single node system AIO-SX

Last pass
--------
Never

Test Activity
--------
Manual

[Ghada Khalil (gkhalil)]

Marking as stx.3.0 / medium priority - this issue prevents simplex systems from being properly configured in the oam interface is down.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/683014

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/683014
Committed: https://git.openstack.org/cgit/starlingx/ha/commit/?id=2966c89c1cb754432284506da1c6a7ce6aeec069
Submitter: Zuul
Branch: master

commit 2966c89c1cb754432284506da1c6a7ce6aeec069
Author: Bin Qian <email address hidden>
Date: Wed Sep 18 21:26:42 2019 -0400

    Ensure in AIO-SX, i/f down does not block node going enabled

    AIO-SX by design does not have a peer, so it never needs to
    communicate potential peer before determining its role. For
    AIO-SX even all network interfaces are down, the node should
    still go enabled based on the situation of the node.

    Closes-Bug: 1844427

    Change-Id: Iafe0a8209cdbd3f83514c07041856cf6b6824f9c
    Signed-off-by: Bin Qian <email address hidden>