To run MySQL on dotcloud is very easy, just follow the documentation:

add the following lines to dotcloud.yml:

then push the app, and run

to get the mysql password.

We suggest you should create your own user/pass for each specific app:

Then we’re done. So far, we run the wordpress on Amazon EC2, and keep the mysql database on dotCloud. Next step we will move the wordpress files from EC2 to dotCloud (AFAIK, it’s on EC2, too), to keep platform-maintain-free. :p