Allow some configure-mirrors repositories to be disabled

Out-of-the-box installs of centos-8 do not enable the PowerTools
or HighAvailability repositories. Debian/Ubuntu do not enable
the backports repository by default.

Having these repos enabled by default in CI has led to merging
broken code for OpenStack deployment tooling which is attempting
to also manage the presence/absence of these repositories. It
is challenging to remove these repositories on the running node
because the repo URL (rather than just the name) is required as
input to the apt_repository and yum_repository ansible modules.

This patch adds a role default variable to configure-mirrors to
allow a job to opt out of these extra repositories. The default
is set to 'True' to allow existing jobs to work as before.

Change-Id: I74b9de7092f182c942a58ac7a46b9fbd791889de

roles/configure-mirrors/README.rst

@@ -30,3 +30,14 @@ An ansible role to configure services to use mirrors.
    Set to True in order to tag APT mirrors as trusted, needed
    when accessing unsigned mirrors with newer releases like
    Ubuntu Bionic.
+
+-- zuul:rolevar:: configure_mirrors_extra_repos
+   :default: True
+
+   Set to False to opt-out of installing extra repositories such
+   as PowerTools and HighAvailability on centos-8-stream and
+   backports for Debian/Ubuntu. The intent is to match the upstream
+   distro state when this variable is set to False. Note that this
+   role is not necessarily consistent with the repos that are
+   enabled by default between distribution versions (centos stream
+   8 vs. 9 for example).

roles/configure-mirrors/defaults/main.yaml

@@ -10,3 +10,4 @@ http_or_https: >-
   {%- endif -%}
 pypi_mirror: "{{ http_or_https }}://{{ pypi_fqdn }}/pypi/simple"
 wheel_mirror: "{{ http_or_https }}://{{ mirror_fqdn }}/wheel/{{ ansible_distribution | lower }}-{{ ansible_distribution_version }}-{{ ansible_architecture | lower }}"
+configure_mirrors_extra_repos: True

roles/configure-mirrors/tasks/mirror/Debian.yaml

@@ -1,18 +1,20 @@
 - name: Install Debian repository files
   become: yes
   template:
-    dest: "/{{ zj_repo }}"
+    dest: "/{{ zj_repo.repo }}"
     group: root
     mode: 0644
     owner: root
-    src: "apt/{{ zj_repo }}.j2"
+    src: "apt/{{ zj_repo.repo }}.j2"
   with_items:
-    - etc/apt/sources.list.d/default.list
-    - etc/apt/sources.list.d/updates.list
-    - etc/apt/sources.list.d/backports.list
-    - etc/apt/sources.list.d/security.list
-    - etc/apt/apt.conf.d/99unauthenticated
+    - repo: etc/apt/sources.list.d/default.list
+    - repo: etc/apt/sources.list.d/updates.list
+    - repo: etc/apt/sources.list.d/backports.list
+      condition: "{{ configure_mirrors_extra_repos }}"
+    - repo: etc/apt/sources.list.d/security.list
+    - repo: etc/apt/apt.conf.d/99unauthenticated
   loop_control:
     loop_var: zj_repo
+  when: zj_repo.condition | default(True) | bool
   notify:
     - Update apt cache

roles/configure-mirrors/templates/apt/etc/apt/sources.list.j2

@@ -1,5 +1,5 @@
 # {{ ansible_managed }}
 deb {% if set_apt_mirrors_trusted %}[ trusted=yes ] {% endif %}{{ package_mirror }} {{ ansible_distribution_release }} main universe
 deb {% if set_apt_mirrors_trusted %}[ trusted=yes ] {% endif %}{{ package_mirror }} {{ ansible_distribution_release }}-updates main universe
-deb {% if set_apt_mirrors_trusted %}[ trusted=yes ] {% endif %}{{ package_mirror }} {{ ansible_distribution_release }}-backports main universe
+{% if configure_mirrors_extra_repos | bool %}deb {% if set_apt_mirrors_trusted %}[ trusted=yes ] {% endif %}{{ package_mirror }} {{ ansible_distribution_release }}-backports main universe{% endif %}
 deb {% if set_apt_mirrors_trusted %}[ trusted=yes ] {% endif %}{{ package_mirror }} {{ ansible_distribution_release }}-security main universe

roles/configure-mirrors/templates/centos8-stream/etc/yum.repos.d/CentOS-Stream-HighAvailability.repo.j2

@@ -3,5 +3,5 @@
 name=CentOS-Stream - HighAvailability
 baseurl={{ package_mirror }}/$stream/HighAvailability/$basearch/os/
 gpgcheck=1
-enabled=1
+enabled="{{ configure_mirrors_extra_repos | bool | ternary('1', '0') }}"
 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

roles/configure-mirrors/templates/centos8-stream/etc/yum.repos.d/CentOS-Stream-PowerTools.repo.j2

@@ -3,5 +3,5 @@
 name=CentOS-Stream - PowerTools
 baseurl={{ package_mirror }}/$stream/PowerTools/$basearch/os/
 gpgcheck=1
-enabled=1
+enabled="{{ configure_mirrors_extra_repos | bool | ternary('1', '0') }}"
 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial