[Linux] In "Drupal on Linux Web App with MySQL" it doesn't allow you to use local on instance DB but template states it have local MYSQL DB
Either the template is having some issues or it's wrongly stated in the template and local MySQL DB is not available in this template.
In either case, you need to correct either the template or template description.
Drupal using Local MySQL can be used with this image manually : appsvcorg/drupal-nginx-fpm:0.2.
For documentation , please see the following https://github.com/Azure-App-Service/drupal-nginx-fpm
We are looking into long term solution for fully supporting Local MySQL similar to MySQL in-app