Comment by eropple

I test and deploy in Docker containers because the artifact that's produced is simpler to deal with. I don't have to specify packages in a Chef cookbook or Ansible playbook, then figure out how to best automate the running of those, then figure out how to do it fast enough to support rapid deploys. And while I run Fedora locally, it presents an abstraction layer that's sufficient, in the 99% case, that developers on a Mac can test predictably; as a trivial example, the Dockerfile specifies an informal but strong interface with regards to environment variables, configuration files, and network ports. (That goes down to like 95% with Windows, but I haven't worked on it with WSL2 yet.)

Treating Docker containers as artifacts--as Configurable, Better Tarballs--by itself is a significant improvement for much of the non-JVM world, and even does have some benefits for the JVM world as well.

Trying to do local dev in it is silly, IMO, but there's real value to shipping Docker containers to wherever you want to actually run the thing.