I originally started using Docker shortly after 0.6.0 was released. A lot has changed since then and for the most part; all the better. But there are many things I wish someone had told me when I started using Docker.
Persistence Nothing removed unless you tell Docker to.
- Volumes are fantastic; but unless you start your containers with the -rm flag your data should not disappear magically. You will have to inspect the old container that was running to determine where the root filesystem is, but it's there.
If the exit command does not exit succesfully the container; it will not be used as cache in the future. This can lead to wasting time building images as you have to re-download Java each time you build.
Help Diagnose Problems If you get stuck with something; you can share your image with peers to help you diagnose the problem. They can then either tell you what they did to fix your image or send you the fixed image.