ensure-virtualenv: Don't support on CentOS 9-stream

It looks like 9-stream don't want to support virtualenv.  Fail the
ensure-virtualenv role on this platform, and account for this in
testing.

People should use ensure-pip and venv which is portable everywhere.

Change-Id: Ifae93c1eeb96792aa26a624574d595d77cb58c4b

roles/ensure-virtualenv/tasks/RedHat.yaml

@@ -1,6 +1,16 @@
+# It looks like CentOS 9 has no plans to support this,
+# and we should be using "python3 -m venv". [1]
+#
+# ensure-pip already exports 'ensure_pip_virtualenv_command'
+#
+# [1] https://lists.centos.org/pipermail/centos-devel/2021-August/098470.html
+- name: Fail on CentOS 9
+  fail:
+    msg: 'This element not supported on CentOS >= 9'
+  when: (ansible_facts['distribution'] == 'CentOS' and ansible_facts['distribution_major_version']|int >= 9)
+
 - name: Install virtualenv
   package:
     name:
       - python3-virtualenv
   become: yes
-

test-playbooks/ensure-pip.yaml

@@ -36,6 +36,10 @@
         $run_pip wheel --no-deps .
         ls zuul-*.whl || exit 1
 
+    - name: Test virtualenv
+      # NOTE(ianw) 2022-02-03 : not supported on 9-stream, see inline comments
+      when: not (ansible_facts['distribution'] == 'CentOS' and  ansible_facts['distribution_major_version']|int >= 9)
+      block:
         # ensure-virtualenv
         - name: Include ensure-virtualenv
           include_role: