Before first run of docker-compose up -d you should initialize the secret storage. This can be done with the following command:

mkdir -p secrets
pwgen 42 1 > secrets/db_root_password
pwgen 42 1 > secrets/admin_secret_key 

TODO explain:

• howto create secrets/admin_sqla_uri
• initialize Database:

this could be add to /etc/pdns/mysql-postinit of powerdns container

create database pdna;
create user 'pdna'@'%' IDENTIFIED BY 'PASSWORD';
GRANT ALL PRIVILEGES ON pdna.* TO 'pdna'@'%';
flush privileges;

And generate required data storages:

mkdir -p data/mysql