I have a java application which currently runs inside of a tomcat instance. This application has like 3-6 (depending on the use) webapps. I would like to pack this application into a docker container to setup a new test system infrastructure.
What would be the best strategy to do that? Pack every webapp into a tomcat based container and bind it with docker-compose (I would prefer that but I'm not sure if that is even possible?) or have one tomcat based container with all webapps in it.
Does anyone have experience with it?
It depends on what you want - there's no simple answer for what you're looking for.
The options I see are:
As you can see, each approach has advantages and disadvantages, it really depends on what you want. The second approach with a single image/container per app is more flexible, but requires more configuration, and has a bit more overhead in that you would be running 6 Tomcat instances instead of just one.
For what it's worth, I use the second approach for my use case. I have a base Tomcat image that is shared across all apps, it's based on the official Docker Tomcat image, and adds a couple of common things. Then each app has its own image with additional configuration, and then I use Docker Compose to pull it all together.
If you don't care about the added flexibility and all of your apps will always have the same lifecycle, then the first approach might also work - it all depends and what you're trying to do.