debian: Remove kolla-ansible-debian-zun job

* When the Debian job got upgraded from Bullseye
  to Bookworm, the non-voting Zun job started failing.
* This is because Debian Bookworm doesn't support the
  required Docker 20 pinning.
* Until Zun gains support for newer dependencies this
  job will keep failing.

Change-Id: I1e1d9ea7c76d1b2f77b09b7948f138b88ef483d2

doc/source/reference/compute/zun-guide.rst

@@ -33,6 +33,10 @@ to cap docker by setting the following variables in globals.yml.
    docker_apt_package_pin: "5:20.*"
    docker_yum_package_pin: "20.*"
 
+Debian Bookworm is not recommended as a host OS for Zun.
+It does not support a version of Docker with the deprecated option.
+Compatibility with Zun is not tested in CI.
+
 Docker reconfiguration requires rebootstrapping before deploy.
 Make sure you understand the consequences of restarting Docker.
 Please see :ref:`rebootstrapping` for details.

releasenotes/notes/zun-drop-bullseye-3259e0bb8995d3ad.yaml

+---
+upgrade:
+  - |
+    Zun is currently incompatible with Debian Bookworm. This is because Zun
+    currently has a hard dependency on a deprecated Docker feature. Operators
+    upgrading from Bullseye are strongly encouraged to disable Zun first.
+    While workarounds may be possible, none are currently tested in CI.

zuul.d/jobs.yaml

@@ -203,13 +203,6 @@
     vars:
       base_distro: rocky
 
-- job:
-    name: kolla-ansible-debian-zun
-    parent: kolla-ansible-zun-base
-    nodeset: kolla-ansible-debian-bookworm-multi
-    vars:
-      base_distro: debian
-
 - job:
     name: kolla-ansible-ubuntu-zun
     parent: kolla-ansible-zun-base

zuul.d/project.yaml

@@ -23,7 +23,6 @@
         - kolla-ansible-rocky9-bifrost
         - kolla-ansible-ubuntu-bifrost
         - kolla-ansible-rocky9-zun
-        - kolla-ansible-debian-zun
         - kolla-ansible-ubuntu-zun
         - kolla-ansible-rocky9-swift
         - kolla-ansible-ubuntu-swift