The Data at Rest Encryption document's "Configuration using Ansible" section contains the following:
First, add the following configuration in the gateway group_vars configuration file (oiosds/products/sds/group_vars/oioswift.yml):
The Ansible playbook repository's /products/sds directory does not contain a group_vars directory. A file named oioswift.yml exists in the playbooks directory, but I'm not certain whether this is the new location of the file that used to be in group_vars, or if it's a different file by the same name.