> turn-key, repeatable dev environments

> We should embrace containers for what they are

Um.. relatively unrelated to the problem you described?

Containers are about isolating one or more processes, memory, network, disk etc from the rest of the host system. This can be used to achieve security benefits, and/or to resolve dependency differences.

The problem of repeatable dev environments is solved almost always by a single concept: script it, either using shell scripts, or a configuration tool like Chef, Puppet, etc.

In Vagrant, this means one or more provisioning scripts executed in the guest environment (usually a VM, might be LXC or Docker). In Packer, this peans one or more provisioning scripts executed in the guest environment (usually a VM, might be LXC or Docker). In Docker, surprise fucking surprise, it's a script executed in the guest environment.

No, they are not unrelated. Isolation yes, and through that, you get repeatability. We can all agree that declaratively describing your environment (Salt, Chef) is preferable to the rather simplistic Dockerfiles currently in use, but both aim to accomplish the same time. I remember the pre-container days of re-running Salt/Puppet scripts over and over again in a VM until it works. Nothing wrong with that - they're great tools. I also remember the pre-Salt/Puppet days of using shell scripts. None of the above are great: conf. management + docker is a better solution long-term for building a container image.

My point is that Docker itself brings nothing to that 'repeatability' table. You have that with shell scripts, salt/chef/puppet/what have you, all of which can be run on any environment that meets the baseline requirements for your project.

It's fairly common to use Docker to run other services (database, cache, etc.) needed when developing a web app.

I assume you're talking about running multiple images concurrently, each one focussed on it's own specific role.

Sure, you can do that too with Vagrant. Vagrant isn't limited to running a single machine for a given Vagrantfile.

On what technology? Working with .net + nuget the environment is generally pretty repeatable, the only big outside dependencies to worry about are the .net framework itself and sql server. Others like java and rust are pretty similar AFAICT.