Fix IPA image download

The IPA ramdisk and kernel images may be built or downloaded via a URL.
If the latter option is used, any images previously downloaded to
$KOLLA_CONFIG_PATH/config/ironic/ironic-agent.* would previously not be
updated if the image contents change.

This change introduces variables for setting a URL to a file containing
checksums for the images. The algorithm used to compute the checksum is
also configurable (default sha256). This allows us to ensure we are
using the correct version of the image, while avoiding an expensive few
hundred megabyte image download just to check.

If a checksum is not specified, the image will be downloaded every time
to ensure that it is up to date.

Change-Id: I8120518ed98d61f3652f5205ce7ec9f798ab2aa1
Story: 2001660
Task: 6693

ansible/group_vars/all/bifrost

@@ -79,9 +79,21 @@ kolla_bifrost_inspector_deploy_ramdisk: "http://{{ provision_oc_net_name | net_i
 # URL of Ironic Python Agent (IPA) kernel image.
 kolla_bifrost_ipa_kernel_upstream_url: "{{ inspector_ipa_kernel_upstream_url }}"
 
+# URL of checksum of Ironic Python Agent (IPA) kernel image.
+kolla_bifrost_ipa_kernel_checksum_url: "{{ inspector_ipa_kernel_checksum_url }}"
+
+# Algorithm of checksum of Ironic Python Agent (IPA) kernel image.
+kolla_bifrost_ipa_kernel_checksum_algorithm: "{{ inspector_ipa_kernel_checksum_algorithm }}"
+
 # URL of Ironic Python Agent (IPA) ramdisk image.
 kolla_bifrost_ipa_ramdisk_upstream_url: "{{ inspector_ipa_ramdisk_upstream_url }}"
 
+# URL of checksum of Ironic Python Agent (IPA) ramdisk image.
+kolla_bifrost_ipa_ramdisk_checksum_url: "{{ inspector_ipa_ramdisk_checksum_url }}"
+
+# Algorithm of checksum of Ironic Python Agent (IPA) ramdisk image.
+kolla_bifrost_ipa_ramdisk_checksum_algorithm: "{{ inspector_ipa_ramdisk_checksum_algorithm }}"
+
 ###############################################################################
 # Inventory configuration.
 

ansible/group_vars/all/inspector

@@ -8,9 +8,21 @@ inspector_extra_kernel_options: "{{ ipa_kernel_options }}"
 # URL of Ironic Python Agent (IPA) kernel image.
 inspector_ipa_kernel_upstream_url: "{{ ipa_kernel_upstream_url }}"
 
+# URL of checksum of Ironic Python Agent (IPA) kernel image.
+inspector_ipa_kernel_checksum_url: "{{ ipa_kernel_checksum_url }}"
+
+# Algorithm of checksum of Ironic Python Agent (IPA) kernel image.
+inspector_ipa_kernel_checksum_algorithm: "{{ ipa_kernel_checksum_algorithm }}"
+
 # URL of Ironic Python Agent (IPA) ramdisk image.
 inspector_ipa_ramdisk_upstream_url: "{{ ipa_ramdisk_upstream_url }}"
 
+# URL of checksum of Ironic Python Agent (IPA) ramdisk image.
+inspector_ipa_ramdisk_checksum_url: "{{ ipa_ramdisk_checksum_url }}"
+
+# Algorithm of checksum of Ironic Python Agent (IPA) ramdisk image.
+inspector_ipa_ramdisk_checksum_algorithm: "{{ ipa_ramdisk_checksum_algorithm }}"
+
 ###############################################################################
 # Ironic inspector processing configuration.
 

ansible/group_vars/all/ipa

@@ -65,12 +65,24 @@ ipa_images_kernel_name: "ipa.vmlinuz"
 # URL of Ironic deployment kernel image to download.
 ipa_kernel_upstream_url: "https://tarballs.openstack.org/ironic-python-agent/coreos/files/coreos_production_pxe-stable-queens.vmlinuz"
 
+# URL of checksum of Ironic deployment kernel image.
+ipa_kernel_checksum_url: "{{ ipa_kernel_upstream_url }}.{{ ipa_kernel_checksum_algorithm }}"
+
+# Algorithm of checksum of Ironic deployment kernel image.
+ipa_kernel_checksum_algorithm: "sha256"
+
 # Name of Ironic deployment ramdisk image to register in Glance.
 ipa_images_ramdisk_name: "ipa.initramfs"
 
 # URL of Ironic deployment ramdisk image to download.
 ipa_ramdisk_upstream_url: "https://tarballs.openstack.org/ironic-python-agent/coreos/files/coreos_production_pxe_image-oem-stable-queens.cpio.gz"
 
+# URL of checksum of Ironic deployment ramdisk image.
+ipa_ramdisk_checksum_url: "{{ ipa_ramdisk_upstream_url }}.{{ ipa_ramdisk_checksum_algorithm }}"
+
+# Algorithm of checksum of Ironic deployment ramdisk image.
+ipa_ramdisk_checksum_algorithm: "sha256"
+
 ###############################################################################
 # Ironic Python Agent (IPA) deployment configuration.
 

ansible/kolla-openstack.yml

@@ -171,7 +171,11 @@
             - name: Set facts containing IPA kernel and ramdisk URLs
               set_fact:
                 kolla_inspector_ipa_kernel_upstream_url: "{{ inspector_ipa_kernel_upstream_url }}"
+                kolla_inspector_ipa_kernel_checksum_url: "{{ inspector_ipa_kernel_checksum_url }}"
+                kolla_inspector_ipa_kernel_checksum_algorithm: "{{ inspector_ipa_kernel_checksum_algorithm }}"
                 kolla_inspector_ipa_ramdisk_upstream_url: "{{ inspector_ipa_ramdisk_upstream_url }}"
+                kolla_inspector_ipa_ramdisk_checksum_url: "{{ inspector_ipa_ramdisk_checksum_url }}"
+                kolla_inspector_ipa_ramdisk_checksum_algorithm: "{{ inspector_ipa_ramdisk_checksum_algorithm }}"
               when: not ipa_build_images | bool
 
             - name: Set facts containing IPA kernel and ramdisk paths

ansible/overcloud-ipa-images.yml

@@ -58,7 +58,11 @@
       set_fact:
         # Don't pass the kernel and ramdisk image URLs if using built images.
         ipa_images_kernel_url: "{{ ipa_kernel_upstream_url }}"
+        ipa_images_kernel_checksum_url: "{{ ipa_kernel_checksum_url }}"
+        ipa_images_kernel_checksum_algorithm: "{{ ipa_kernel_checksum_algorithm }}"
         ipa_images_ramdisk_url: "{{ ipa_ramdisk_upstream_url }}"
+        ipa_images_ramdisk_checksum_url: "{{ ipa_ramdisk_checksum_url }}"
+        ipa_images_ramdisk_checksum_algorithm: "{{ ipa_ramdisk_checksum_algorithm }}"
       when: not ipa_build_images | bool
 
     - name: Check whether the image cache directory exists

ansible/roles/image-download/defaults/main.yml

@@ -0,0 +1,19 @@
+---
+# URL of the image.
+# Mutually exclusive with image_download_path.
+image_download_url:
+
+# URL of a checksum of the image.
+# Mutually exclusive with image_download_path.
+image_download_checksum_url:
+
+# Algorithm of a checksum of the image.
+# Mutually exclusive with image_download_path.
+image_download_checksum_algorithm:
+
+# Path to a local file containing the image.
+# Mutually exclusive with image_download_url.
+image_download_path:
+
+# Path to the image's destination.
+image_download_dest:

ansible/roles/image-download/tasks/main.yml

@@ -0,0 +1,42 @@
+---
+- block:
+    - block:
+        - name: Fail if the checksum algorithm is not set
+          fail:
+            msg: "Checksum algorithm for image {{ image_download_url }} not set"
+          when: image_download_checksum_algorithm is none or
+                image_download_checksum_algorithm == ""
+
+        - name: Get the expected checksum
+          uri:
+            url: "{{ image_download_checksum_url }}"
+            return_content: true
+          register: expected_checksum
+      when:
+        - image_download_checksum_url is not none
+        - image_download_checksum_url != ""
+
+    - name: Ensure the image is downloaded
+      vars:
+        checksum: "{{ image_download_checksum_algorithm }}:{{ expected_checksum.content.split(' ')[0] }}"
+      get_url:
+        url: "{{ image_download_url }}"
+        dest: "{{ image_download_dest }}"
+        mode: 0640
+        # If the file exists locally, its checksum will be compared with this.
+        checksum: "{{ checksum if expected_checksum is not skipped else omit }}"
+        # Always download the image if we have no checksum to compare with.
+        force: "{{ expected_checksum is skipped }}"
+        backup: true
+  when:
+    - image_download_url is not none
+    - image_download_url != ""
+
+- name: Ensure the local image is copied
+  copy:
+    src: "{{ image_download_path }}"
+    dest: "{{ image_download_dest }}"
+    mode: 0640
+  when:
+    - image_download_path is not none
+    - image_download_path != ""

ansible/roles/ipa-images/defaults/main.yml

@@ -24,6 +24,12 @@ ipa_images_kernel_name:
 # image in ipa_images_cache_path will be used.
 ipa_images_kernel_url:
 
+# URL of checksum of Ironic deployment kernel image.
+ipa_images_kernel_checksum_url:
+
+# Algorithm of checksum of Ironic deployment kernel image.
+ipa_images_kernel_checksum_algorithm:
+
 # Name of Ironic deployment ramdisk image to register in Glance.
 ipa_images_ramdisk_name:
 
@@ -31,6 +37,12 @@ ipa_images_ramdisk_name:
 # image in ipa_images_cache_path will be used.
 ipa_images_ramdisk_url:
 
+# URL of checksum of Ironic deployment ramdisk image.
+ipa_images_ramdisk_checksum_url:
+
+# Algorithm of checksum of Ironic deployment ramdisk image.
+ipa_images_ramdisk_checksum_algorithm:
+
 # Ansible host pattern for limiting which nodes are updated with deploy_ramdisk
 # and deploy_kernel properties
 ipa_images_compute_node_limit: baremetal-compute

ansible/roles/ipa-images/tasks/main.yml

@@ -7,18 +7,26 @@
     group: "{{ ansible_user_gid }}"
   become: True
 
-- name: Ensure Ironic Python Agent (IPA) images are downloaded
-  get_url:
-    url: "{{ item.url }}"
-    dest: "{{ ipa_images_cache_path }}/{{ item.filename }}"
-    force: true
-    backup: true
+- name: Ensure Ironic Python Agent (IPA) images are present
+  vars:
+    image_download_url: "{{ item.url }}"
+    image_download_checksum_url: "{{ item.checksum_url }}"
+    image_download_checksum_algorithm: "{{ item.checksum_algorithm }}"
+    image_download_dest: "{{ item.dest }}"
+  include_role:
+    name: image-download
   with_items:
     - url: "{{ ipa_images_kernel_url }}"
-      filename: "{{ ipa_images_kernel_name }}"
+      checksum_url: "{{ ipa_images_kernel_checksum_url }}"
+      checksum_algorithm: "{{ ipa_images_kernel_checksum_algorithm }}"
+      dest: "{{ ipa_images_cache_path }}/{{ ipa_images_kernel_name }}"
     - url: "{{ ipa_images_ramdisk_url }}"
-      filename: "{{ ipa_images_ramdisk_name }}"
-  when: item.url != None
+      checksum_url: "{{ ipa_images_ramdisk_checksum_url }}"
+      checksum_algorithm: "{{ ipa_images_ramdisk_checksum_algorithm }}"
+      dest: "{{ ipa_images_cache_path }}/{{ ipa_images_ramdisk_name }}"
+  when: item.url is not none
+  loop_control:
+    label: "{{ item.dest }}"
 
 - name: Compute the MD5 checksum of the Ironic Python Agent (IPA) images
   stat:

ansible/roles/kolla-bifrost/defaults/main.yml

@@ -58,9 +58,21 @@ kolla_bifrost_download_ipa: true
 # URL of Ironic Python Agent (IPA) kernel image.
 kolla_bifrost_ipa_kernel_upstream_url:
 
+# URL of checksum of Ironic Python Agent (IPA) kernel image.
+kolla_bifrost_ipa_kernel_checksum_url:
+
+# Algorithm of checksum of Ironic Python Agent (IPA) kernel image.
+kolla_bifrost_ipa_kernel_checksum_algorithm:
+
 # URL of Ironic Python Agent (IPA) ramdisk image.
 kolla_bifrost_ipa_ramdisk_upstream_url:
 
+# URL of checksum of Ironic Python Agent (IPA) ramdisk image.
+kolla_bifrost_ipa_ramdisk_checksum_url:
+
+# Algorithm of checksum of Ironic Python Agent (IPA) ramdisk image.
+kolla_bifrost_ipa_ramdisk_checksum_algorithm:
+
 # Server inventory to be configured in {{ kolla_node_custom_config_path }}/bifrost/servers.yml.
 kolla_bifrost_servers: {}
 

ansible/roles/kolla-bifrost/templates/bifrost.yml.j2

@@ -51,11 +51,31 @@ download_ipa: "{{ kolla_bifrost_download_ipa }}"
 ipa_kernel_upstream_url: "{{ kolla_bifrost_ipa_kernel_upstream_url }}"
 {% endif %}
 
+{% if kolla_bifrost_ipa_kernel_checksum_url %}
+# URL of checksum of Ironic Python Agent (IPA) kernel image.
+ipa_kernel_upstream_checksum_url: "{{ kolla_bifrost_ipa_kernel_checksum_url }}"
+{% endif %}
+
+{% if kolla_bifrost_ipa_kernel_checksum_algorithm %}
+# Algorithm of checksum of Ironic Python Agent (IPA) kernel image.
+ipa_kernel_upstream_checksum_algo: "{{ kolla_bifrost_ipa_kernel_checksum_algorithm }}"
+{% endif %}
+
 {% if kolla_bifrost_ipa_ramdisk_upstream_url %}
 # URL of Ironic Python Agent (IPA) ramdisk image.
 ipa_ramdisk_upstream_url: "{{ kolla_bifrost_ipa_ramdisk_upstream_url }}"
 {% endif %}
 
+{% if kolla_bifrost_ipa_ramdisk_checksum_url %}
+# URL of checksum of Ironic Python Agent (IPA) ramdisk image.
+ipa_ramdisk_upstream_checksum_url: "{{ kolla_bifrost_ipa_ramdisk_checksum_url }}"
+{% endif %}
+
+{% if kolla_bifrost_ipa_ramdisk_checksum_algorithm %}
+# Algorithm of checksum of Ironic Python Agent (IPA) ramdisk image.
+ipa_ramdisk_upstream_checksum_algo: "{{ kolla_bifrost_ipa_ramdisk_checksum_algorithm }}"
+{% endif %}
+
 {% if kolla_bifrost_extra_globals %}
 ###############################################################################
 # Extra configuration

ansible/roles/kolla-openstack/defaults/main.yml

@@ -227,10 +227,26 @@ kolla_inspector_extra_kernel_options: []
 # Mutually exclusive with kolla_inspector_ipa_kernel_path.
 kolla_inspector_ipa_kernel_upstream_url:
 
+# URL of checksum of Ironic Python Agent (IPA) kernel image for Ironic
+# inspector. Mutually exclusive with kolla_inspector_ipa_kernel_path.
+kolla_inspector_ipa_kernel_checksum_url:
+
+# Algorithm of checksum of Ironic Python Agent (IPA) kernel image for Ironic
+# inspector. Mutually exclusive with kolla_inspector_ipa_kernel_path.
+kolla_inspector_ipa_kernel_checksum_algorithm:
+
 # URL of Ironic Python Agent (IPA) ramdisk image for Ironic Inspector.
 # Mutually exclusive with kolla_inspector_ipa_ramdisk_path.
 kolla_inspector_ipa_ramdisk_upstream_url:
 
+# URL of checksum of Ironic Python Agent (IPA) ramdisk image for Ironic
+# Inspector. Mutually exclusive with kolla_inspector_ipa_ramdisk_path.
+kolla_inspector_ipa_ramdisk_checksum_url:
+
+# Algorithm of checksum of Ironic Python Agent (IPA) ramdisk image for Ironic
+# Inspector. Mutually exclusive with kolla_inspector_ipa_ramdisk_path.
+kolla_inspector_ipa_ramdisk_checksum_algorithm:
+
 # Path to Ironic Python Agent (IPA) kernel image for Ironic Inspector.
 # Mutually exclusive with kolla_inspector_ipa_kernel_upstream_url.
 kolla_inspector_ipa_kernel_path:

ansible/roles/kolla-openstack/tasks/config.yml

@@ -36,29 +36,29 @@
     - { src: zookeeper.cfg.j2, dest: zookeeper.cfg, enabled: "{{ kolla_enable_zookeeper }}" }
   when: item.enabled | bool
 
-- name: Ensure the ironic inspector kernel and ramdisk are downloaded
-  get_url:
-    url: "{{ item.url }}"
-    dest: "{{ kolla_node_custom_config_path }}/ironic/{{ item.dest }}"
-    mode: 0640
+- name: Ensure ironic inspector kernel and ramdisk images are present
+  vars:
+    image_download_url: "{{ item.url }}"
+    image_download_checksum_url: "{{ item.checksum_url }}"
+    image_download_checksum_algorithm: "{{ item.checksum_algorithm }}"
+    image_download_path: "{{ item.path }}"
+    image_download_dest: "{{ item.dest }}"
+  include_role:
+    name: image-download
   with_items:
-    - { url: "{{ kolla_inspector_ipa_kernel_upstream_url }}", dest: "ironic-agent.kernel" }
-    - { url: "{{ kolla_inspector_ipa_ramdisk_upstream_url }}", dest: "ironic-agent.initramfs" }
-  when:
-    - kolla_enable_ironic | bool
-    - item.url != None
-
-- name: Ensure the ironic inspector kernel and ramdisk are copied
-  copy:
-    src: "{{ item.path }}"
-    dest: "{{ kolla_node_custom_config_path }}/ironic/{{ item.dest }}"
-    mode: 0640
-  with_items:
-    - { path: "{{ kolla_inspector_ipa_kernel_path }}", dest: "ironic-agent.kernel" }
-    - { path: "{{ kolla_inspector_ipa_ramdisk_path }}", dest: "ironic-agent.initramfs" }
-  when:
-    - kolla_enable_ironic | bool
-    - item.path != None
+    - url: "{{ kolla_inspector_ipa_kernel_upstream_url }}"
+      checksum_url: "{{ kolla_inspector_ipa_kernel_checksum_url }}"
+      checksum_algorithm: "{{ kolla_inspector_ipa_kernel_checksum_algorithm }}"
+      path: "{{ kolla_inspector_ipa_kernel_path }}"
+      dest: "{{ kolla_node_custom_config_path }}/ironic/ironic-agent.kernel"
+    - url: "{{ kolla_inspector_ipa_ramdisk_upstream_url }}"
+      checksum_url: "{{ kolla_inspector_ipa_ramdisk_checksum_url }}"
+      checksum_algorithm: "{{ kolla_inspector_ipa_ramdisk_checksum_algorithm }}"
+      path: "{{ kolla_inspector_ipa_ramdisk_path }}"
+      dest: "{{ kolla_node_custom_config_path }}/ironic/ironic-agent.initramfs"
+  when: kolla_enable_ironic | bool
+  loop_control:
+    label: "{{ item.dest }}"
 
 # We support a fairly flexible mechanism of dropping config file templates into
 # an 'extra' config directory, and passing these through to kolla-ansible. We

doc/source/upgrading.rst

@@ -145,9 +145,17 @@ Upgrading Ironic Deployment Images
 
 Prior to upgrading the OpenStack control plane you should upgrade
 the deployment images. If you are using prebuilt images, update
-``ipa_kernel_upstream_url`` and ``ipa_ramdisk_upstream_url`` in
-``etc/kayobe/ipa.yml``, alternatively, you can update the files that the URLs
-point to. If building the images locally, follow the process outlined in
+the following variables in ``etc/kayobe/ipa.yml`` accordingly:
+
+* ``ipa_kernel_upstream_url``
+* ``ipa_kernel_checksum_url``
+* ``ipa_kernel_checksum_algorithm``
+* ``ipa_ramdisk_upstream_url``
+* ``ipa_ramdisk_checksum_url``
+* ``ipa_ramdisk_checksum_algorithm``
+
+Alternatively, you can update the files that the URLs point to. If building the
+images locally, follow the process outlined in
 :ref:`building_ironic_deployment_images`.
 
 To get Ironic to use an updated set of overcloud deployment images, you can run::

etc/kayobe/bifrost.yml

@@ -69,6 +69,27 @@
 # Ironic inspector deployment ramdisk location.
 #kolla_bifrost_inspector_deploy_ramdisk:
 
+###############################################################################
+# Ironic Python Agent (IPA) configuration.
+
+# URL of Ironic Python Agent (IPA) kernel image.
+#kolla_bifrost_ipa_kernel_upstream_url:
+
+# URL of checksum of Ironic Python Agent (IPA) kernel image.
+#kolla_bifrost_ipa_kernel_checksum_url:
+
+# Algorithm of checksum of Ironic Python Agent (IPA) kernel image.
+#kolla_bifrost_ipa_kernel_checksum_algorithm:
+
+# URL of Ironic Python Agent (IPA) ramdisk image.
+#kolla_bifrost_ipa_ramdisk_upstream_url:
+
+# URL of checksum of Ironic Python Agent (IPA) ramdisk image.
+#kolla_bifrost_ipa_ramdisk_checksum_url:
+
+# Algorithm of checksum of Ironic Python Agent (IPA) ramdisk image.
+#kolla_bifrost_ipa_ramdisk_checksum_algorithm:
+
 ###############################################################################
 # Inventory configuration.
 

etc/kayobe/inspector.yml

@@ -8,9 +8,21 @@
 # URL of Ironic Python Agent (IPA) kernel image.
 #inspector_ipa_kernel_upstream_url:
 
+# URL of checksum of Ironic Python Agent (IPA) kernel image.
+#inspector_ipa_kernel_checksum_url:
+
+# Algorithm of checksum of Ironic Python Agent (IPA) kernel image.
+#inspector_ipa_kernel_checksum_algorithm:
+
 # URL of Ironic Python Agent (IPA) ramdisk image.
 #inspector_ipa_ramdisk_upstream_url:
 
+# URL of checksum of Ironic Python Agent (IPA) ramdisk image.
+#inspector_ipa_ramdisk_checksum_url:
+
+# Algorithm of checksum of Ironic Python Agent (IPA) ramdisk image.
+#inspector_ipa_ramdisk_checksum_algorithm:
+
 ###############################################################################
 # Ironic inspector processing configuration.
 

etc/kayobe/ipa.yml

@@ -56,12 +56,24 @@
 # URL of Ironic deployment kernel image to download.
 #ipa_kernel_upstream_url:
 
+# URL of checksum of Ironic deployment kernel image.
+#ipa_kernel_checksum_url:
+
+# Algorithm of checksum of Ironic deployment kernel image.
+#ipa_kernel_checksum_algorithm:
+
 # Name of Ironic deployment ramdisk image to register in Glance.
 #ipa_images_ramdisk_name:
 
 # URL of Ironic deployment ramdisk image to download.
 #ipa_ramdisk_upstream_url:
 
+# URL of checksum of Ironic deployment ramdisk image.
+#ipa_ramdisk_checksum_url:
+
+# Algorithm of checksum of Ironic deployment ramdisk image.
+#ipa_ramdisk_checksum_algorithm:
+
 ###############################################################################
 # Ironic Python Agent (IPA) deployment configuration.
 

releasenotes/notes/fix-ipa-image-download-3f90f0f40d0feafd.yaml

@@ -0,0 +1,36 @@
+---
+upgrade:
+  - |
+    It is now possible to specify a URL of a file containing a checksum of the
+    Ironic Python Agent (IPA) images for the seed and overcloud Ironic and
+    Ironic Inspector services. This allows Kayobe to detect changes in the
+    image content and download as necessary. If specifying IPA images via URL,
+    the checksums should be configured accordingly.
+
+    The checksum URLs and algorithms are configured via these variables:
+
+    * ``{{ ipa_kernel_checksum_url }}``
+    * ``{{ ipa_kernel_checksum_algorithm }}``
+    * ``{{ ipa_ramdisk_checksum_url }}``
+    * ``{{ ipa_ramdisk_checksum_algorithm }}``
+
+    For the seed this may be customised via these variables:
+
+    * ``{{ kolla_bifrost_ipa_kernel_checksum_url }}``
+    * ``{{ kolla_bifrost_ipa_kernel_checksum_algorithm }}``
+    * ``{{ kolla_bifrost_ipa_ramdisk_checksum_url }}``
+    * ``{{ kolla_bifrost_ipa_ramdisk_checksum_algorithm }}``
+
+    For the overcloud Ironic Inspector service this may be customised via these
+    variables:
+
+    * ``{{ inspector_ipa_kernel_checksum_url }}``
+    * ``{{ inspector_ipa_kernel_checksum_algorithm }}``
+    * ``{{ inspector_ipa_ramdisk_checksum_url }}``
+    * ``{{ inspector_ipa_ramdisk_checksum_algorithm }}``
+fixes:
+  - |
+    Fixes an issue with downloading Ironic Python Agent (IPA) images where new
+    images would not be downloaded if the image had been downloaded previously.
+    See `Story 2001660 <https://storyboard.openstack.org/#!/story/2001660>`__
+    for details.