Goal: 

• Add the following known issue to the 17.1 FFU guide:
  • .Unsupported service causes upgrade to fail
    During an upgrade from RHOSP 16.2 to 17.1, the overcloud upgrade fails because the environment uses the following unsupported service in the `upgrade_tasks_step3.yaml` file:
    `OS::TripleO::Services::OVNDBs: deployment/ovn/ovn-dbs-pacemaker-puppet.yaml`

Workaround:

. Replace `OS::TripleO::Services::OVNDBs: deployment/ovn/ovn-dbs-pacemaker-puppet.yaml` with the following service:
+

OS::TripleO::Services::OVNDBs: deployment/ovn/ovn-dbs-cluster-ansible.yaml

. Update the configuration:
+

$ source stackrc
$ chmod 755 /home/stack/overcloud_upgrade_prepare.sh
$ sh /home/stack/overcloud_upgrade_prepare.sh

. Run the overcloud upgrade:
+

$ openstack overcloud upgrade run --yes --stack <stack> --debug --limit allovercloud,undercloud --playbook all

Acceptance Criteria:

• Known issue is published in the 17.1 FFU guide.