Switch default IPA images to centos

The CoreOS images are no longer built or maintained.

Change-Id: I8928c2def85070f6310e5fb859abf21b3e234256
Story: 2007021
Task: 37808

ansible/group_vars/all/ipa

@@ -63,7 +63,7 @@ ipa_images_upstream_url_suffix: "-{{ openstack_branch | replace('/', '-') }}"
 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{{ ipa_images_upstream_url_suffix }}.vmlinuz"
+ipa_kernel_upstream_url: "https://tarballs.openstack.org/ironic-python-agent/dib/files/ipa-centos7{{ ipa_images_upstream_url_suffix }}.kernel"
 
 # URL of checksum of Ironic deployment kernel image.
 ipa_kernel_checksum_url: "{{ ipa_kernel_upstream_url }}.{{ ipa_kernel_checksum_algorithm }}"
@@ -75,7 +75,7 @@ ipa_kernel_checksum_algorithm: "sha256"
 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{{ ipa_images_upstream_url_suffix }}.cpio.gz"
+ipa_ramdisk_upstream_url: "https://tarballs.openstack.org/ironic-python-agent/dib/files/ipa-centos7{{ ipa_images_upstream_url_suffix }}.initramfs"
 
 # URL of checksum of Ironic deployment ramdisk image.
 ipa_ramdisk_checksum_url: "{{ ipa_ramdisk_upstream_url }}.{{ ipa_ramdisk_checksum_algorithm }}"

releasenotes/notes/centos-ipa-images-60dde12f2b4f4f8c.yaml

+---
+upgrade:
+  - |
+    The default IPA images now use CentOS as a base image. This is
+    because CoreOS based images are no longer supported or built by
+    the upstream Ironic Python Agent project as of the Train release.
+    Please see the `Ironic Python Agent release notes for more details
+    <https://docs.openstack.org/releasenotes/ironic-python-agent/train.html>`_.