Add image platform argument

roles/os_images/README.md

@@ -27,8 +27,8 @@ on the build host.
 
 `os_images_cache`: a path to a directory in which to cache build artefacts.
 It defaults to `~/disk_images`
-`NOTE`: new images will NOT be built, even if changes are made in config, if an image is already cached.
-Use `force_rebuild` flag in order to apply new config changes.
+`NOTE`: new images will NOT be built, even if changes are made in config, if an image
+is already cached. Use `force_rebuild` flag in order to apply new config changes.
 
 `os_images_auth_type`: OpenStack authentication endpoint and credentials.
 Defaults to `password`.
@@ -57,25 +57,34 @@ mutually exclusive where each contain:
   This is a dict of the form of `KEY: VALUE`.
 * `packages`: (optional) list of packages to install in the image.
 * `size`: (optional) size to make the image filesystem.
+* `architecture`: (optional) image CPU architecture to pass to diskimage-builder `-a`.
+  If unset, default to the diskimage-builder default architecture: `x86_64`, and upload
+  Glance images with the `cpu_arch: "x86_64"` image property. If architecture is set
+  to `arm64` or `aarch64`, Glance images with the `cpu_arch: "aarch64"` image property
+  When setting to other values, consider also setting `properties.cpu_arch` to a
+  corresponding value.
 * `properties`: (optional) dict of properties to set on the glance image.
   Common image properties are available
   [here](https://docs.openstack.org/glance/latest/user/common-image-properties.html).
 * `type`: (optional) image type. Default in DIB is qcow2. Image formats are
   available [here](https://docs.openstack.org/glance/latest/user/formats.html).
-* `force_rebuild`: (optional) boolean flag indicating whether or not the image should always
-  be built (even if an existing image that name has been built before). The images on glance
-  will be replaced if `os_images_upload` is set to `True`. This defaults to
+* `force_rebuild`: (optional) boolean flag indicating whether or not the image should
+  always be built (even if an existing image that name has been built before). The images
+  in glance will be replaced if `os_images_upload` is set to `True`. This defaults to
   `os_images_force_rebuild`if left unset.
-* `is_public`: (optional) (deprecated - use `visibility`) whether the image should be set as visible to all
-  projects or kept private. Note that if both `is_public` and `visibility` are provided, `is_public` will 
-  be preferred.
+* `is_public`: (optional) (deprecated - use `visibility`) whether the image should be set
+  as visible to all projects or kept private. Note that if both `is_public` and `visibility`
+  are provided, `is_public` will be preferred.
 * `visibility`: (optional) Allowed values are 'public', 'private', 'shared'
-or 'community'. Default is 'public'
+  or 'community'. Default is 'public'
 * `owner`: (optional) ID of the project that should own the uploaded image.
 
 `os_images_common`: A set of elements to include in every image listed.
 Defaults to `cloud-init enable-serial-console stable-interface-names`.
 
+`os_images_common_properties`: A dict of Glance image properties to set on all images.
+Defaults to an empty dict, and is overridden by `os_images_list.*.properties`.
+
 `os_images_dib_pkg_name`: Optionally customise the name parameter passed 
 to the ansible.builtin.pip module when installing diskimage-builder. This can
 be used to install diskimage-builder from version control.
@@ -96,27 +105,50 @@ following parameters:
 
 `os_images_upload`: Whether to upload built images to Glance. Defaults to `True`.
 
-`os_images_force_rebuild`: Whether or not to force a rebuild of the DIB image. The images on Glance
-will be replaced with the newly built image if `os_images_upload` is set to `True`. Defaults to
-`False`.
+`os_images_force_rebuild`: Whether or not to force a rebuild of the DIB image.
+The images on Glance will be replaced with the newly built image if `os_images_upload`
+is set to `True`. Defaults to `False`.
 
-`os_images_public`: (Deprecated - use `os_images_visibility`) Whether uploaded images are public. Defaults to `True` - note this requires admin permissions. 
+`os_images_public`: (Deprecated - use `os_images_visibility`) Whether uploaded
+images are public. Defaults to `True` - note this requires admin permissions.
 
-`os_images_visibility`: The visibility of images uploaded. One of `community`,`public` or `private`. If unset, defaults to `os_images_public` (requires admin permissions for anything other than `private`)
+`os_images_visibility`: The visibility of images uploaded. One of `community`,
+`public` or `private`. If unset, defaults to `os_images_public` (requires admin
+permissions for anything other than `private`)
 
-`os_images_venv`: Path to virtualenv in which to install python dependencies to upload images.
+`os_images_venv`: Path to virtualenv in which to install python dependencies to
+upload images.
 
 `os_images_dib_venv`: Path to virtualenv in which to install DIB to build images.
 
 `os_images_promote`: Whether or not to promote new images. Defaults to `False`.
 
-`os_images_retire`: Whether or not to retire old images. Defaults to `os_image_promote`. May be necessary to set separately if you are promoting a new candidate image for which there is no existing one to retire, for example. 
+`os_images_retire`: Whether or not to retire old images. Defaults to `os_image_promote`.
+May be necessary to set separately if you are promoting a new candidate image for which
+there is no existing one to retire, for example.
 
 `os_images_build`: Whether or not to build the images.
 
-`os_images_name_suffix`: Image suffix which would be removed during image promotion, for exmple: -rc, -dev, -test etc. Mandatory for promotion functionality. Empty by default.
+`os_images_name_suffix`: Image suffix which would be removed during image promotion, for
+exmple: -rc, -dev, -test etc. Mandatory for promotion functionality. Empty by default.
+
+`os_images_hide`: Whether or not to hide the images in Glance list. Hiding images is
+available as an option in image retirement/promotion process. Defaults to `False`.
+
+Changing platform architecture in os_images
+-------------------------------------------
+
+The target CPU architecture for each image defined in `os_images_list` may be set to any
+architecture supported by diskimage-builder with the `architecture` parameter.
+
+If it is unset, an image with the default diskimage-builder architecture (`x86_64`) will
+be built and optionally uploaded to Glance, with the Glance image property `cpu_arch` set
+to `x86_64`. If it is set to `arm64` or `aarch64`, images will be uploaded to Glance with
+the Glance image property `cpu_arch` set to `aarch64`.
 
-`os_images_hide`: Whether or not to hide the images in Glance list. Hiding images is available as an option in image retirement/promotion process. Defaults to `False`.
+If setting to a different `architecture`, consider also setting `properties.cpu_arch` to an
+architecture
+[supported by Glance](https://docs.openstack.org/glance/latest/admin/useful-image-properties.html#image-property-keys-and-values).
 
 Dependencies
 ------------

roles/os_images/defaults/main.yml

@@ -45,8 +45,7 @@ os_images_common: cloud-init enable-serial-console stable-interface-names
 #     type: qcow2
 os_images_list: []
 # Common properties to apply to all glance images.
-os_images_common_properties:
-  cpu_arch: x86_64
+os_images_common_properties: {}
 
 # OpenStack authentication type: passed to the os_image Ansible module
 os_images_auth_type: password

roles/os_images/tasks/images.yml

@@ -83,8 +83,9 @@
 - name: Generate diskimage-builder images
   vars:
     dib_args: >-
-      {% if item.size is defined %}--image-size {{ item.size }}{% endif %} {% if item.type is defined %}-t {{ item.type }}{% endif %} {% if item.packages | default
-      %}-p {{ item.packages | join(',') }}{% endif %} {{ os_images_common }} {{ item.elements | join(' ') }} -o {{ item.name }}
+      {% if item.size is defined %}--image-size {{ item.size }}{% endif %} {% if item.type is defined %}-t {{ item.type }}{% endif %}
+      {% if item.packages | default %}-p {{ item.packages | join(',') }}{% endif %} {{ os_images_common }} {{ item.elements | join(' ') }}
+      -o {{ item.name }} {% if item.architecture is defined %}-a {{ item.architecture }}{% endif %}
   ansible.builtin.shell: . {{ os_images_dib_venv }}/bin/activate && disk-image-create {{ dib_args }} > {{ item.name }}.stdout 2> {{ item.name }}.stderr
   args:
     chdir: "{{ os_images_cache }}/{{ item.name }}"

roles/os_images/tasks/prereqs.yml

@@ -29,3 +29,15 @@
     state: directory
     mode: "0755"
   become: true
+
+- name: Run multiarch/qemu-user-static image to support cross-arch build
+  ansible.builtin.command:
+    # We already have a precheck for presence of docker executable so use it here
+    cmd: docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
+  # Using --reset means that we always change something
+  changed_when: true
+  become: true
+  when: os_images_list |
+        selectattr("architecture", "defined") |
+        rejectattr("architecture", "equalto", ansible_facts.architecture) |
+        length > 0

roles/os_images/tasks/upload.yml

@@ -110,10 +110,22 @@
     container_format: bare
     disk_format: "{{ item.0.type | default('qcow2') }}"
     filename: "{{ os_images_cache }}/{{ item.0.name }}/{{ item.0.name }}.{{ item.0.type | default('qcow2') }}"
-    properties: "{{ os_images_common_properties | combine(item.0.properties | default({})) or omit }}"
+    properties: "{{ os_images_common_properties | combine(cpu_arch_properties) | combine(item.0.properties | default({})) or omit }}"
     kernel: "{{ item.1.id if is_baremetal else omit }}"
     ramdisk: "{{ item.2.id if is_baremetal else omit }}"
   vars:
+    # NOTE(m-anson): When architecture isn't defined for an
+    # image, assume that we should set cpu_arch: x86_64 as
+    # this is the diskimage-builder default. If an architecture
+    # of arm64 or aarch64 is defined, set cpu_arch: aarch64. In
+    # all other cases, leave it up to the operator to set
+    # properties.cpu_arch.
+    cpu_arch_properties: >-
+      {{
+          {"cpu_arch": "aarch64"}
+          if (item.0.architecture is defined and item.0.architecture in ["arm64", "aarch64"])
+          else ({"cpu_arch": "x86_64"} if item.0.architecture is not defined else {})
+      }}
     is_baremetal: "{{ item.0.elements is defined and 'baremetal' in item.0.elements }}"
     visibility: "{{ item.0.visibility | default(item.0.is_public | ternary('public', 'private') if item.0.is_public is defined else os_images_visibility) }}"
   with_together: