Update seed VM image to CentOS 8.2

If using a CentOS 8.2 bifrost_deploy image on a CentOS 8.1 seed host, we
may see an error such as the following:

    TASK [Ensure the overcloud host image has bogus name server entries removed]
    fatal: [seed]: FAILED!

Running virt-customize with more debug in the Bifrost container, we see
this output:

qemu-kvm: error: failed to set MSR 0x48e to 0xfff9fffe04006172
qemu-kvm: /builddir/build/BUILD/qemu-4.2.0/target/i386/kvm.c:2695: kvm_buf_set_msrs: Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed.

This appears to be an incompatibility between qemu/libvirt in CentOS 8.1
and 8.2.

This change fixes the issue for new deployments by updating the seed VM
image to CentOS 8.2.  Existing deployments will need to update packages
on the seed host to match the bifrost_deploy container.

Change-Id: Icf64b15e58c84f31a11cdefcdb79558b58737da1
Story: 2007942
Task: 40407

ansible/group_vars/all/seed-vm

@@ -41,7 +41,7 @@ seed_vm_root_capacity: 50G
 seed_vm_root_format: qcow2
 
 # Base image for the seed VM root volume.
-seed_vm_root_image: "https://cloud.centos.org/centos/8/x86_64/images/CentOS-8-GenericCloud-8.1.1911-20200113.3.x86_64.qcow2"
+seed_vm_root_image: "https://cloud.centos.org/centos/8/x86_64/images/CentOS-8-GenericCloud-8.2.2004-20200611.2.x86_64.qcow2"
 
 # Capacity of the seed VM data volume.
 seed_vm_data_capacity: 100G

etc/kayobe/seed-vm.yml

@@ -24,7 +24,7 @@
 #seed_vm_root_format:
 
 # Base image for the seed VM root volume. Default is
-# "https://cloud.centos.org/centos/8/x86_64/images/CentOS-8-GenericCloud-8.1.1911-20200113.3.x86_64.qcow2".
+# "https://cloud.centos.org/centos/8/x86_64/images/CentOS-8-GenericCloud-8.2.2004-20200611.2.x86_64.qcow2".
 #seed_vm_root_image:
 
 # Capacity of the seed VM data volume.

releasenotes/notes/seed-vm-centos-8.2-36b7a480a7725da1.yaml

+---
+features:
+  - |
+    Updates the default image for the seed VM to CentOS 8.2.
+fixes:
+  - |
+    Fixes an issue with seed service deployment where modifying the overcloud
+    image fails on a CentOS 8.1 host with a CentOS 8.2 ``bifrost_deploy``
+    container, by updating the default image for the seed VM to CentOS 8.2.
+    See `story 2007942 <https://storyboard.openstack.org/#!/story/2007942>`__
+    for details.