New dns servers (e.g. pdns) never get their list of zones populated

I just rebuilt one of my designate/pdns nodes, and discovered that the list of zones (called 'domains' in pdns) isn't populated. That meant that basically all axfr requests from designate-mdns to pdns were failing.

I resolved this by dumping the 'domains' table from one of the working pdns nodes and importing it on the new node.

Ideally there would be a designate-manage command (dns-manage pdns populate?) which explicitly synchronizes the pdns database state with the designate state. Failing that we should at least document a process for populating things.