Old timer to 2 other old timers: Docker does solve a problem, and this is quite close to it... We had a solution that we needed to install on servers for multiple clients. Before Docker, we had to make sure the libraries were correct (on CentOS, Debian, Ubuntu,... you name it), which was a nightmare. We were literally debugging on customers' installations to see why it broke there.

Docker solves this nicely. Apart from the kernel you take all dependencies with you.

In this case, it provides an easy installation of all the dependencies in a single command, while still allowing for customizations, and all in a standard way. Not to mention that certificates and similar are all solved.

Forget about hype and just try Docker. It's a tool like any other. It can be abused, sure, but it's useful too and it's here to stay.

EDIT: difference between Java and Docker is that containers depend on kernel capabilities, not on some 3rd party JAR maintainers. In my experience Docker simply works unless you are doing something really weird.

I've been using Docker for lots of things. To be honest, the dependency part has been helpful but still weak: we inevitably end up finding that our containers are built from things that go stale (apt-get sources, pip, broken URLs, stale SSL certs, etc). I guess there is a skill to doing it well so that this doesn't happen, but there you are - it didn't really solve the problem it's now an extra skill we need to have to solve a problem we had already mostly solved.

What has really sold me is more the orchestration side, with docker-compose allowing us to easily launch a whole fleet of independent services. I assume swarm and kubernetes etc., make this even better. It's really this that lets us decompose our software into finer grained independent components which has a number of other benefits. I don't think we could manage it otherwise.

You still need to do a frequent build to detect broken dependencies, but at least setting up a daily docker build in CI is so much simpler and faster (and cross-platform!) than doing this with vagrant or live systems. At least you'll catch problems a lot sooner.

If you want to protect yourself from breaking dependencies, mirror them locally, and use a network-isolated docker build to verify you've actually got everything you need.

The build process might break because of stale links, like you say, but already built images should continue to function everywhere unless you're doing something really weird.