[CI] Use compatible version of heat-tempest-plugin

This is a combination of five patch to fix the gate:

1. Use compatible version of heat-tempest-plugin

heat-tempest-plugin dropped py38 support, hence it cannot be installed
from recent master, so we need to override the checkout to the version
that still supports py38 and compatible to the actual branch.

This is needed both for the grenade job and the functional job, because
these are using the heat-tempest-plugin.

2. Try archive path to download Fedora image

This is a temporal workaround to allow downloading Fedora 37 image
which was moved to the archive path.

3. Remove reference to devstack-gate

devstack-gate was deprecated in xena and is being retired now[1].

4. [stable-only] Cap setuptools <71.0.0

py39 jobs (on ubuntu-focal) started to fail due to recent virtualenv
release (20.26.4) on Yoga (which bundles setuptools), because we have
'packaging==21.3' in this branch that is not compatible with newer
setuptools [2].

setuptools is bundled in virtualenv, so it has to be capped via the
virtualenv package. tox also needed to be capped (<4) as gate uses
tox 3.28.0, but with capping virtualenv we pull in latest tox as well,
which would cause other errors.

5. Set functional jobs as non-voting

heat-functional jobs try to install python-zaqarclient (via zaqar
project) from master branch, but on master the client dropped py38
support, hence the jobs fail. This patch sets it non-voting as a
quick workaround until a final fix arrives.

[1] https://review.opendev.org/c/openstack/governance/+/919629
[2] pypa/setuptools#4483

Changes:
  .zuul.yaml

NOTE(elod.illes): change in .zuul.yaml is to adapt the patch to the
current branch ('<series>-last' needs to be used).

Change-Id: I9b1702749976a2cea42a24130e5fec2931b75ce1
(cherry picked from commit a806b40)
(cherry picked from commit ae62258)
(cherry picked from commit 4fd9953)
(cherry picked from commit 81a8b93)
(cherry picked from commit 665ccfc)
(cherry picked from commit c18b344)
(cherry picked from commit dcf7403)

.zuul.yaml

@@ -10,11 +10,11 @@
       - zuul: opendev.org/openstack/devstack
       - zuul: opendev.org/openstack/tempest
     required-projects:
-      - openstack/devstack-gate
       - openstack/barbican
       - openstack/heat
       - openstack/heat-templates
-      - openstack/heat-tempest-plugin
+      - name: opendev.org/openstack/heat-tempest-plugin
+        override-checkout: yoga-last
       - openstack/octavia
       - openstack/neutron
       - openstack/oslo.messaging
@@ -139,7 +139,8 @@
     voting: false
     required-projects:
       - opendev.org/openstack/heat
-      - opendev.org/openstack/heat-tempest-plugin
+      - name: opendev.org/openstack/heat-tempest-plugin
+        override-checkout: yoga-last
       - opendev.org/openstack/python-heatclient
     vars:
       grenade_devstack_localrc:
@@ -197,10 +198,20 @@
     check:
       jobs:
         - grenade-heat-multinode
-        - heat-functional
-        - heat-functional-legacy
+        # NOTE(elod.illes): functional jobs are failing due to
+        # python-zaqarclient dropped py38 support and even on
+        # this old branch the client is installed from master
+        # as a quick workaround this is now set as non-voting
+        - heat-functional:
+            voting: false
+        - heat-functional-legacy:
+            voting: false
     gate:
       jobs:
         - grenade-heat-multinode
-        - heat-functional
-        - heat-functional-legacy
+        # NOTE(elod.illes): functional jobs are failing due to
+        # python-zaqarclient dropped py38 support and even on
+        # this old branch the client is installed from master
+        # as a quick workaround this is now removed from gate
+        # - heat-functional
+        # - heat-functional-legacy

devstack/lib/heat

@@ -478,11 +478,14 @@ function configure_tempest_for_heat {
         source /etc/ci/mirror_info.sh
     fi
     HEAT_TEST_FEDORA_IMAGE_UPSTREAM=https://download.fedoraproject.org/pub/fedora/linux
+    HEAT_TEST_FEDORA_IMAGE_UPSTREAM_ARCHIVE=https://download.fedoraproject.org/pub/archive/fedora/linux/
     HEAT_TEST_FEDORA_IMAGE_PATH=releases/37/Cloud/x86_64/images/Fedora-Cloud-Base-37-1.7.x86_64.qcow2
-    if curl --output /dev/null --silent --head --fail "${NODEPOOL_FEDORA_MIRROR}/${HEAT_TEST_FEDORA_IMAGE_PATH}"; then
+    if curl --location --output /dev/null --silent --head --fail "${NODEPOOL_FEDORA_MIRROR}/${HEAT_TEST_FEDORA_IMAGE_PATH}"; then
         export HEAT_TEST_FEDORA_IMAGE="${NODEPOOL_FEDORA_MIRROR}/${HEAT_TEST_FEDORA_IMAGE_PATH}"
-    else
+    elif curl --location --output /dev/null --silent --head --fail "${HEAT_TEST_FEDORA_IMAGE_UPSTREAM}/${HEAT_TEST_FEDORA_IMAGE_PATH}"; then
         export HEAT_TEST_FEDORA_IMAGE="${HEAT_TEST_FEDORA_IMAGE_UPSTREAM}/${HEAT_TEST_FEDORA_IMAGE_PATH}"
+    else
+        export HEAT_TEST_FEDORA_IMAGE="${HEAT_TEST_FEDORA_IMAGE_UPSTREAM_ARCHIVE}/${HEAT_TEST_FEDORA_IMAGE_PATH}"
     fi
     TOKEN=$(openstack token issue -c id -f value)
     local image_exists=$( openstack image list | grep "Fedora-Cloud-Base-37-1.7.x86_64" )

tox.ini

@@ -3,6 +3,12 @@ envlist = py36,py37,py38,pep8
 ignore_basepython_conflict = True
 minversion = 3.1.0
 skipsdist = True
+# Cap setuptools via virtualenv to prevent compatibility issue with yoga
+# branch's upper constraint of 'packaging' package (21.3).
+requires =
+  virtualenv<20.26.4
+  tox<4
+  setuptools<71.0.0
 
 [testenv]
 basepython = python3