What other solution for the easy portability do you know? Or how would you propose to handle this?

If it is easier then docker build && docker push and docker pull on the other side I'm all ears!

If upstream supplies a decent docker image, chances are that means the package is more amenable to scripting and running in a chroot/jail/container - and documents it dependencies somewhat.

That said, snaphotting the "state" of your container/jail can be nice. Recently I used the official ruby images, and could build a custom image to use with our self-hosted gitlab (with built-in docker registry) that a) got a standard Debian based ruby image and applied updates, and b) built freetds for connecting to mssql.

Now I can quickly update that base image as needed, while the CI jobs testing our rails projects "only" need a "bundle install" before running tests.

And the scripts are largely reusable across heterogeneous ruby versions (yes I hope we can get all projects up on a recent ruby..).

Puppet for the server-automation part. Languages that make it easy to produce a "fat binary" for the isolation part.

Docker solves a real problem for languages where deployment is a mess, like Python. It just grates on me when the same people who spent the last 10 years mocking Java (which does essentially the useful parts of docker) are suddenly enthusiastic about the same kind of solution to the same kind of problem now that it has a trendy name.

You're arguing a point never made. That containers make things portable is not saying that's the ONLY thing that makes things portable.

I find using containers a lot easier to be portable when I have multiple apps that bizarrely require different versions of, say, python, or python libs and the same version of python.

Although, it's not exactly the same thing, because with Docker you have everything already installed in the image. I've only used Ansible and I was never happy with its dynamic nature.

Docker (all container solutions really) aren't a panacea, but they solve a very real problem.

If it looks waaaay different to puppet, ansible and chef, there's a reason for that :) Doing provisioning "properly" means managing every file on the drive...

For example, there's no concept of `Maybe this request failed, you should handle it`. So when you run the deployment script, the request fails and the rest of your deployment process.

Defining the possibility of failure with a type system would force you to handle it in your deployment code and provide a backup solution.