To be fair, it's been a while since I've looked at it, so it could have matured quite a while. I should give it more of a chance. My impression was probably also coloured by not liking Python... Other than that, the main objection I had was that it seemed on one hand that writing charms seemed over-complicated (might have been coloured by the Pyhthon examples..) , and that there seemed to be too much "magic" in the examples. But I looked right after it was released, so it's definitively time for another look.

(EDIT: It actually does look vastly improved over last time; not least the documentation)

Specifically, I run a private cloud at work across a few dozen servers and a bit over a hundred VMs currently, and we very much need control over which physical servers we deploy to because the age and capabilities varies a lot - ranging from ancient single CPU servers to 32 core monstrosities stuffed full of SSDs. They're also in two data centres.

When I last looked at juju it seemed to lack a simple way to specify machines or data centres. I just looked at the site again and it has a "set-constraint" command now that seems to do that.

The second issue is/was deployment. OpenStack or EC2 used to be the only options for deploying other than locally. Local deployment was possible via LXC. EC2 is ludicrously expensive, and OpenStack is ridiculous overkill to us compared to our current system (which is OpenVz - our stack predates LXC - managed via a few hundred lines of Ruby script) .

I don't know if that has changed (will look, though, when I get time away from an annoying IP renumbering exercise...), but we'd need either a lighter option ("bare" LXC or something like Docker on each host would both be ok) or an easy way to hook in our own provisioning script.

(EDIT: I see they've added support for deployment via MAAS at least, which is a great)