Comment 4 for bug 1871332

It is Redis (default in Kolla Ansible):

# grep -A1 coordination /etc/kolla/designate-central/designate.conf
[coordination]
backend_url = redis://xxx:yyy@10.10.10.31:26379?sentinel=kolla&sentinel_fallback=10.10.10.32:26379&sentinel_fallback=10.10.10.33:26379&db=0&socket_timeout=60&retry_on_timeout=yes