Why you need persistent data

Let's consider an example use case where you may want to write data to a persistent location from a container.

Let's say you have a system that requires you to deploy a MySQL database fronted by a web-based application running on NGINX. You start both containers for the application using standard docker run commands. You do some initial testing with the users and they confirm that everything is working as expected. The users were successful when it came to adding records, querying for records, editing, and deletions – this all worked correctly. After a few days of the container running, you receive an email from security telling all users that all MySQL servers need to have a new patch deployed as soon as possible to address a security vulnerability.

You quickly work on a new MySQL image that includes the newest patch and push it to your container registry. Working with the users, you decide a time to deploy the new container and...