Migrate a vBulletin 4 forum to Discourse

I am using standard install.
Referenced https://www.vultr.com/docs/how-to-install-discourse-on-ubuntu-20-04/.
I can not use Mysql on docker installation. I installed MariaDB on discourse docker image.

root@localhost-app:/var/www/discourse# service mysql start
mysql: unrecognized service

So I made mysql docker image and uploaded my vBulletine database there. mysql docker image ip address is

Thank you.