BOA & cloud services?

There is no difference installing boa on any supported server, local or cloud based. Download the scripts to the server and run them as usual.

Were you expecting something else to be possible out of curiosity?

There's hundreds of different cloud service providers all offering very different options but essentially the same thing so maybe I'm missing something in your question?

There's too many variables to give a definitive answer.

You just have to install it, run your sites up on it and measure it accurately with something like Nagios/Munin and watch for trends so you can prepare and make changes to suite.

No single person can tell you what all your sites on aegir will do, or can do until they are running on the production box.

BOA will run on 512 RAM, even less I've heard, though performance will be hurting no doubt and I'd imagine some caching services won't work as expected but don't quote me.

I guess if you're catering for low end hosting clients (one visitor per day) so to speak, it hardly matters how big your aegir server is. If they up and leave your hosting plan you'll know why but if you monitor the server carefully AND constantly you'll know what to do to avoid that going forward.

Hope that helps.

For what its worth, I have multiple BOA instances running on Rackspace Cloud Servers and have no problems. I use their Debian Squeeze image, and control DNS through their web interface.

After creating your image, you run the install per the documentation.

If you are new to cloud computing and things like this, Rackspace's support can prove invaluable. Many times you reach a point where you are wondering "Is it me? Or the server?". They have live chat that you can pop up 24 / 7 and simply ask. Now they can't help with BOA specific things, or even Drupal for that matter, but they can help with server admin type things.