> do use it in development for standing up local dev environments quickly
You can do this, for sure, but, tbh, I'd still rather use Vagrant. I'm already provisioning things like my datastores using Chef (and not deploying those inside of Docker in production); I might as well repurpose the same code to build a dev environment.
I do agree regarding using containers (I use rkt rather than Docker for a few reasons) for CI being a really good jumping-off point, though.
Vagrant is pretty heavy, but if you're already using Chef, makes sense. If you're deploying using Docker, then mirroring your environment in dev makes more sense.
I've used both Vagrant and Docker for dev, and find Docker to be super fast and light. (though I've definitely run into some headaches with Docker Compose that I didn't see in using just Docker)
I think it's probably not worth worrying about "fast" when "slow" is "ten minutes once a week, maybe, if you're really destructive" and similarly worrying about "light" when you have 16GB of RAM and a quad-core processor; the heaviest dev environment/IDE I can find (IntelliJ and a couple hundred Chrome tabs) doesn't use eight of it. It comes off as super-premature optimization to me, and those optimizations that you would otherwise do in Docker (which are just building base images, whatever, Packer does this trivially) exist in a virtualized environment too.
Running datastores in Docker is bonkers in the first place, which still leaves a significant place for an actual CM tool--so unless you are a particular strain of masochist, when you are replicating your local environment, you'll probably need it anyway.
> ten minutes once a week, maybe, if you're really destructive
If you do a lot of active machine development, where you're iterating on that machine setup, it's an extremely slow process. Perhaps it would make sense to iterate in Docker, and then convert that process to Vagrant once you finish.
> similarly worrying about "light" when you have 16GB of RAM and a quad-core processor
It's a concern when you're launching many machines at once to develop against. Docker tends to only eat what it needs.
Also, while I think everyone should have a 16GB machine, there's quite a few developers out there running 8 or 4GB machines.
You can do this, for sure, but, tbh, I'd still rather use Vagrant. I'm already provisioning things like my datastores using Chef (and not deploying those inside of Docker in production); I might as well repurpose the same code to build a dev environment.
I do agree regarding using containers (I use rkt rather than Docker for a few reasons) for CI being a really good jumping-off point, though.