PMM does not allow to easily configure email server so "forgot password" function does not work.
The other potential way to do it would be to use grafana cli
This however does not work out of the box. It is not clear how to run it so it detects and updates correct file.
We should either make it work out of the box or document proper process.
I made it work with
grafana-cli --homepath "/usr/share/grafana" admin reset-admin-password admin
And creating symlink from default grafana.db file to /srv/grafana/grafana.db but I'm not sure if this is the best option