We need to tell the user this: If `overcloud-revert-ovs.sh` creates a file, make sure to specify an absolute path to that file. For example, if you use the --log-file argument, specify the file with an absolute path. The migration revert playbook uses the variable $ANSIBLE_DIR (which defaults to /usr/share/ansible/neutron-ovn-migration). If your creates a file on a relative path, Ansible tries to write it in $ANSIBLE_DIR, where the revert user might not have adequate permissions