All-in-one duplex installation fails to install controller-1 due to dnsmasq start-up error

[M. Vefa Bicakci]

Brief Description
-----------------

While installing StarlingX master branch ISO image from 2023-09-28 onto an All-in-One Duplex system, I encountered the following errors in /var/log/daemon.log, which indicated that dnsmasq did not start.

This prevented PXE booting controller-1 from controller-0, and failed the installation, at least until I created a placeholder file in the same path. (See workaround below.)

```
2023-09-29T14:25:15.584 controller-0 dnsmasq[213534]: crit FAILED to start up
2023-09-29T14:25:55.999 controller-0 dnsmasq[219948]: crit cannot read /opt/platform/config/23.09//dnsmasq.addn_conf: No such file or directory
2023-09-29T14:25:55.999 controller-0 dnsmasq[219948]: crit FAILED to start up
2023-09-29T14:26:36.415 controller-0 dnsmasq[224628]: crit cannot read /opt/platform/config/23.09//dnsmasq.addn_conf: No such file or directory
2023-09-29T14:26:36.415 controller-0 dnsmasq[224628]: crit FAILED to start up
2023-09-29T14:27:16.843 controller-0 dnsmasq[230711]: crit cannot read /opt/platform/config/23.09//dnsmasq.addn_conf: No such file or directory
2023-09-29T14:27:16.843 controller-0 dnsmasq[230711]: crit FAILED to start up
2023-09-29T14:27:57.224 controller-0 dnsmasq[235086]: crit cannot read /opt/platform/config/23.09//dnsmasq.addn_conf: No such file or directory
2023-09-29T14:27:57.224 controller-0 dnsmasq[235086]: crit FAILED to start up
2023-09-29T14:28:37.586 controller-0 dnsmasq[239822]: crit cannot read /opt/platform/config/23.09//dnsmasq.addn_conf: No such file or directory
2023-09-29T14:28:37.586 controller-0 dnsmasq[239822]: crit FAILED to start up
2023-09-29T14:29:18.023 controller-0 dnsmasq[246595]: crit cannot read /opt/platform/config/23.09//dnsmasq.addn_conf: No such file or directory
2023-09-29T14:29:18.023 controller-0 dnsmasq[246595]: crit FAILED to start up
```

Severity
--------
Major: controller-1 cannot be installed in All-in-One Duplex systems

Steps to Reproduce
------------------

Attempt to install an All-in-One Duplex StarlingX system.

Expected Behavior
------------------
Installation ought to be successful for both controller-0 and controller-1.

Actual Behavior
----------------
Installation fails to PXE boot controller-1, so controller-1 cannot be installed.

Reproducibility
---------------
Once only, for now, but I am fairly confident that this is a repeatable/reproducible issue.

System Configuration
--------------------
All-in-One Duplex with IPv6 connectivity.

Branch/Pull Time/Commit
-----------------------

sysadmin@controller-0:~$ cat /etc/build.info
SW_VERSION="23.09"
BUILD_TARGET="Host Installer"
BUILD_TYPE="Formal"
BUILD_ID="20230928T060059Z"
SRC_BUILD_ID="149"

JOB="STX_build_debian_master"
BUILD_BY="jenkins"
BUILD_NUMBER="161"
BUILD_HOST="yow2-wrcp2-lx"
BUILD_DATE="2023-09-28 06:00:59 +0000"

Last Pass
---------
Yes, this is a new issue, but I am not sure when this issue started to occur, as I only attempted such an installation with StarlingX last night.

Timestamp/Logs
--------------
Please see above.

Test Activity
-------------
Normal use.

Workaround
----------

Run the following command on controller-0, and the power-cycle controller-1, so that controller-1 can boot up from PXE boot, when dnsmasq on controller-0 recovers itself:

  sudo touch /opt/platform/config/23.09//dnsmasq.addn_conf

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/stx-puppet/+/896857
Committed: https://opendev.org/starlingx/stx-puppet/commit/1fbc6cdca4bd8d50e7661844b25e1879dc46a8ac
Submitter: "Zuul (22348)"
Branch: master

commit 1fbc6cdca4bd8d50e7661844b25e1879dc46a8ac
Author: Joseph V <email address hidden>
Date: Fri Sep 29 18:38:50 2023 +0000

    Revert "Update dnsmasq conf file for host-record support"

    This reverts commit 6c418b0441460ed018e76cfda0b13c97e240e000.

    Reason for revert: Partial-Bug

    LP: https://bugs.launchpad.net/starlingx/+bug/2037734

    Closes-Bug: 2037734
    Story: 2010835
    Task: 48724

    Change-Id: Ic9779078349fdbfa6e48a9e90bad8f0794b6ddd9