jpetazzo

This combines the advantages of Device Mapper (granularity) and AUFS/overlay (page cache re-use), and doesn't require new kernel code. Promising!

The comparison with systemd is unfair. Docker wants to be "batteries included, but swappable/removable". If you don't like host management, orchestration, build, etc., you can disable that specific component and put another one; and none of those components are strictly necessary.

Contrast with systemd, where it's impossible to use anything else, and the attitude of the maintainers is "our way or the highway" when people beg them to continue to support alternatives.

Compare Docker to frameworks like Django or Rails, which come with everything you need (templating, ORM, url mapping, etc.) but where each thing is replaceable if you don't like it; versus Rocket which would be like Flask or Sinatra, which are smaller and require to be combined with other things to be useful. Nothing wrong with either approach; but if the comparison is right, we can expect Docker to provide "reasonable defaults", and some people building some specific apps to use Rocket because they just want to run things and they don't need build/orchestration/API/etc (or they need special versions of those components).

Actually, Docker doesn't always have docker0; you can configure it to use a different bridge.

On my setup, for instance, I use br0 and share the same bridge for containers and VMs.

FWIW, boot2docker became my favorite all-purpose, ready-to-run, ridiculously-small-and-therefore-insanely-fast-to-download VM image.

It's faster to download it (it's 25 MB) and start it with qemu, than to go through the clicky-pointy interfaces of VirtualBox etc., or go through the download of a full Vagrant box. This is game changing.

I don't know yet what will happen for Windows, but an upcoming version of Docker will run on OS X. (I say "upcoming" because I know some core maintainers have OS X support in their local branches, so it's just a matter of time before it hits master.)

It doesn't has the same isolation guarantees (yet) but it lets you use the same workflow.

Windows is different, but I can't imagine a scenario where you have to run your app on Windows. I.e. if it's your local machine, you can spin up a VM; if it's in your datacenter, you can use Linux. If your local policies are "we only run Windows on our servers, screw Linux!" chances are that you wouldn't run Docker anyway, even if it ran natively on Windows :-)

"A few systems that support LXC", that's actually most modern Linux systems now. Anything with a 3.8 kernel is game.

Indeed; for the lucky ones around here with a bare metal Linux box, just substitute kvm instead and ROCK ON!

Just do:

    wget https://github.com/steeve/boot2docker/releases/download/v0.1/boot2docker.iso
    qemu-system-x86_64 -cdrom boot2docker.iso -m 1024

Mind. Blown.