We need a service user with enough access to create/append/delete TXT records under the DNS zone toolforge.org.
This service user will be used by acme-chief to fulfill dns-01 challenges from Let's Encrypt.
Following the naming schema used in the deployment-prep and traffic projects tools-dns-manager could be the name for this service account. See https://wikitech.wikimedia.org/wiki/Portal:Cloud_VPS/Admin/Service_accounts for service account information.