Application state is an important consideration when you're running applications in containers. Containers can be long-running, but they are not intended to be permanent. One of the biggest advantages with containers over traditional compute models is that you can easily replace them, and it only takes a few seconds to do so. When you have a new feature to deploy, or a security vulnerability to patch, you just build and test an upgraded image, stop the old container, and start a replacement from the new image.
Volumes let you manage that upgrade process by keeping your data separate from your application container. I'll demonstrate this with a simple web application that stores the hit count for a ...
