Understanding MySQL the Access Denied error in or outside a Docker container I once wasted more than a full workday fighting the MySQL error message Access denied for user (using password: YES). After finding the solution I want to help others avoid this problem. Along the way to fixing the issue, I learned a lot about how MySQL authenticates user ID's. I've been using MySQL for years and had glossed over this topic, but it turns out to both not be terribly difficult, and very crucial to the solution.

Using multiple databases and PHPMyAdmin in a single MySQL Docker instance Sometimes our applications need multiple database, but with a single database server instance. The typical recommendation is for each Docker container to serve a single application. For databases, that means one database server for each application. That's the result of following a theoretical best practice, but isn't there another best practice to avoid excess processes and overhead? MySQL, like most other database servers, can support multiple databases, multiple user identities, and has an extensive system for controlling access on IP address, user names, and passwords. The MySQL container for Docker is easy to use, but supports only a single database instance per server container. In this article let's learn how to go ahead and configure the MySQL container for Docker to support multiple databases each with their own user ID.