Windows Azure - Deploying to subset of instances within a role

I'm looking to implement continuous deployment, pretty much as a proof of concept using Windows Azure, deploying the packages and switching staging <-> production is all fine, however, I would like to add some smarts to the way it is deployed.

Essentially, if I have 10 instances, I want to deploy to all in the staging slot, and switch say 3 of them to production and monitor to make sure there is no statistical error difference between those 3 and the other 7 before switching all to production, or if there is, switch those 3 back to the original production which is now running in staging.

Essentially I want to mimic the sym link switching as described at http://timothyfitz.wordpress.com/2009/02/10/continuous-deployment-at-imvu-doing-the-impossible-fifty-times-a-day/

From what I can see, Azure only allows an all or nothing approach when switching between production and staging?开发者_如何学编程 I also thought about having two sets of roles defined, but the issue is there the same end point cant be used in two roles (I dont think?).

Anyone know of a way to do this?

Do a manual in-place upgrade. Then the update will happen one update domain at a time (and you can define how many update domains you want... default is five). If you set it to manual, you're in charge of when you move on to the next update domain. If something goes wrong, you start a new in-place upgrade to the old bits again.