Make the convert-image role more generic

Specifically this patch adds knobs for controlling whether:
- an update is run (convert_image_update)
- what packages get removed (convert_image_remove_pkgs)
- what packages get installed (convert_image_install_pkgs)
- what tempest plugins get installed (convert_image_tempest-plugins)

All defaults for the above options are set to the current hardcoded
values, so this is a no-op change wrt current configurations.
However, it allows for new configurations to take advantage of this
feature.

Change-Id: Iecb2d07e4451eb97c958dcf19d9a76aa0982acef
Related-Bug: 1719902

releasenotes/notes/generic-convert-image-5605efaea6828aad.yaml

@@ -0,0 +1,9 @@
+---
+features:
+  - |
+    Added the ability to better control what happens when converting an
+    overcloud-full.qcow2 image into an undercloud image. It is now possible to
+    change whether an update is run (convert_image_update|bool), what packages
+    should be removed (convert_image_remove_pkgs|list), what packages should
+    be installed (convert_image_install_pkgs|list, and what tempest plugins
+    should be installed (convert_image_tempest_plugins|list).

roles/convert-image/README.md

@@ -0,0 +1,21 @@
+# Convert an overcloud-full.qcow2 into an image to boot an undercloud from
+
+The `convert-image` role transforms a overcloud-full image into one which an
+undercloud can be booted from in order to save time on package installs, while
+not needing to maintain/host a specific undercloud image.
+
+## Variables
+
+* `convert_image_working_dir`: -- directory to be used for image conversion
+* `convert_image_template`: jinja template for the script which does the
+  conversion
+* `convert_image_update`: Boolean controlling whether to run an update as part
+  of the image conversion
+* `convert_image_remove_pkgs`: List of packages that need to be removed from
+  the overcloud image
+* `convert_image_install_pkgs`: List of packages that need to be installed on
+  the overcloud image
+* `convert_image_tempest_plugins`: List of tempest plugins to install (This is
+  separate from the install list so that it can be allowed to fail without
+  failing the conversion)
+

roles/convert-image/defaults/main.yml

@@ -2,3 +2,32 @@
 convert_image_working_dir: "{{ working_dir }}"
 convert_image_template: convert_image.sh.j2
 
+# Do a yum update when converting overcloud to undercloud
+convert_image_update: true
+
+# List of packages that should be removed from the overcloud image
+convert_image_remove_pkgs:
+  - cloud-init
+  - python-django-horizon
+  - openstack-dashboard
+
+# List of packages that should be installed to convert overcloud to undercloud
+convert_image_install_pkgs:
+  - python-tripleoclient
+
+# List of tempest plugins to install. This is separated from the other install
+# packages list, because it is allowed to fail if there is some issue
+# installing the tempest plugins.
+convert_image_tempest_plugins:
+  - openstack-tempest
+  - python-aodh-tests
+  - python-ceilometer-tests
+  - python-heat-tests
+  - python-ironic-tests
+  - python-keystone-tests
+  - python-manila-tests
+  - python-mistral-tests
+  - python-neutron-tests
+  - python-sahara-tests
+  - python-zaqar-tests
+

roles/convert-image/templates/convert_image.sh.j2

@@ -15,19 +15,18 @@ fi
 
 {% if not undercloud_setup|bool %}
 
+{% if convert_image_update|bool %}
 yum update -y
+{% endif %}
 
-yum remove -y cloud-init python-django-horizon openstack-dashboard
-yum install -y python-tripleoclient
+yum remove -y {{ convert_image_remove_pkgs|join(" ") }}
+yum install -y {{ convert_image_install_pkgs|join(" ") }}
 # NOTE(trown) Install tempest and test packages in a seperate yum transaction
 # so that we do not fail the conversion if this install fails. There is a period
 # after TripleO uploads a new image, but before the buildlogs repo gets synced,
 # where this will fail because we try to install older test packages than the
 # service packages already installed in the image.
-yum install -y openstack-tempest python-aodh-tests python-ceilometer-tests \
-python-heat-tests python-ironic-tests python-keystone-tests python-manila-tests \
-python-mistral-tests python-neutron-tests python-sahara-tests python-zaqar-tests \
-|| /bin/true
+yum install -y {{ convert_image_tempest_plugins|join(" ") }} || /bin/true
 
 {% endif %}