downgrade: fail to downgrade controller-0 after upgrade

[Bin Qian]

Brief Description

Platform downgrade on controller-0 fails.
Sysinv error on FileExistsError: [Errno 17] File exists: '/var/pxeboot/pxelinux.cfg/efi-01-24-8a-07-58-d0-a0' -> '/var/pxeboot/pxelinux.cfg/efi-01-24-8a-07-58-d0-a0.cfg'

Severity
Critical:

Steps to Reproduce
1. Follow the upgrade procedure and upgrade from 21.12 to 22.12. Stop continuing upgrade procedure after upgrading controller-0
2. Start following Upgrade abort procedure after controller-0 as per the procedure.
3. While downgrading controller-0 failure happened and Downgrade was not started.

Expected Behavior

Able to downgrade Controller-0 from Controller-1

Actual Behavior

[sysadmin@controller-1 ~(keystone_admin)]$ system host-list
+----+--------------+-------------+----------------+-------------+--------------+
| id | hostname | personality | administrative | operational | availability |
+----+--------------+-------------+----------------+-------------+--------------+
| 1 | controller-0 | controller | locked | disabled | online |
| 2 | compute-0 | worker | locked | disabled | offline |
| 3 | compute-1 | worker | locked | disabled | offline |
| 4 | controller-1 | controller | unlocked | enabled | available |
+----+--------------+-------------+----------------+-------------+--------------+
[sysadmin@controller-1 ~(keystone_admin)]$ system host-downgrade 1
Remote error: FileExistsError [Errno 17] File exists: '/var/pxeboot/pxelinux.cfg/efi-01-24-8a-07-58-d0-a0' -> '/var/pxeboot/pxelinux.cfg/efi-01-24-8a-07-58-d0-a0.cfg'
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/zerorpc/core.py", line 167, in _async_task
    functor.pattern.process_call(self._context, bufchan, event, functor)
  File "/usr/lib/python3/dist-packages/zerorpc/patterns.py", line 30, in process_call
    result = functor(*req_event.args, **req_event.kwargs)
  File "/usr/lib/python3/dist-packages/zerorpc/decorators.py", line 44, in __call__
    return self._functor(*args, **kargs)
  File "/usr/lib/python3/dist-packages/sysinv/zmq_rpc/zmq_rpc.py", line 39, in method
    retval = getattr(self.target, func)(context, **kwargs)
  File "/usr/lib/python3/dist-packages/sysinv/conductor/manager.py", line 12069, in upgrade_ihost_pxe_config
    self._update_pxe_config(host, load)
  File "/usr/lib/python3/dist-packages/sysinv/conductor/manager.py", line 1350, in _update_pxe_config
    os.symlink(source, link_name)
FileExistsError: [Errno 17] File exists: '/var/pxeboot/pxelinux.cfg/efi-01-24-8a-07-58-d0-a0' -> '/var/pxeboot/pxelinux.cfg/efi-01-24-8a-07-58-d0-a0.cfg'
.

Reproducibility
always

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/config/+/880065

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/config/+/880065
Committed: https://opendev.org/starlingx/config/commit/a234501420bf75bfc140ab984df0cdf239a83e5c
Submitter: "Zuul (22348)"
Branch: master

commit a234501420bf75bfc140ab984df0cdf239a83e5c
Author: Bin Qian <email address hidden>
Date: Tue Apr 11 16:22:37 2023 +0000

    Create pxeboot cfg link for 22.12 pxeinstall only

    This fix is to only create link:
    efi-01-<dashed_mac> -> efi-01-<dashed_mac>.cfg when creating
    pxeboot cfg file for 22.12 or later installation.

    Closes-Bug: 2015893

    TCs:
        Downgrade after controller-0 upgraded to 22.12 from 21.12.

    Signed-off-by: Bin Qian <email address hidden>
    Change-Id: Icdcc2cbd77f1781044219dd70a59f894edb1e675