You need to configure PowerDNS to use the MySQL backend.
First enable the MySQL backend:
launch = gmysql
Configure the MySQL database settings:
gmysql-host=<host>
gmysql-port=
gmysql-dbname=<dbname>
gmysql-user=<username>
gmysql-password=<password>
gmysql-dnssec=yes
#gmysql-socket=<socket path>
Note
PowerDNS can connect via socket or host/port.
Configure the options for designate-central - specifaclly “connection” to point to your MySQL database:
[backend:powerdns]
connection = mysql://<username>:<password>@<host>:<port>/<dbname>
Setup the database schema.
$ designate-manage powerdns init
$ designate-manage powerdns sync