I'm looking to set up two web roles or websites on my Azure Cloud Service.
The websites need to share the same database schema. I use NHibernate ORM, so I have to make sure that both projects are always using the same data model, or else it will cause major problems.
I've researched setting up multiple websites on a single web role (which seems odd to me, can't I just run multiple web roles, each with a single site)?
http://msdn.microsoft.com/en-us/library/windowsazure/gg433110.aspx
Like any good developer, I use a staging server. If I have to manually set the domain name is configuration files, how will azure know not to be sending people who visit that domain to the staging server?! I.E. If they visit blah.foo.com and I have two deployments (staging and production), is IIS going to be able to know only to send people to the production environment?
Please advise on the best way to go about doing this.
First, you can certainly have multiple web roles, each with a single site; however, each role instance will be deployed to different virtual machines. For example, if you do set up two web roles when you deploy this with one instance each then there are two virtual machines you'll be paying for. If you want the SLA to apply to your deployment you'd need to actually set the instance count to 2 for each web role, which now means you have four virtual machines running. By combining web sites onto the same web role you'll cut down on the number of instances you need to run and still get the SLA; however, that option is not without some considersations. The link you provided is how you can set up multiple websites to run on the same virtual machine when deployed. Note that there are some gotchas with using that method. I'd suggest reading Michael Collier's Tips for Publishing Multiple Sites in a Web Role.
Second, if you do NOT need to have a lot of control over the virtual machine (such as registering special components, etc.) you might want to look at Windows Azure Web Sites as an option. You can elect to take one of the paid levels of Web Sites and still have dedicated machines, but you can deploy the websites separately. I will say though, that your requirement of having both sites in lock step because they share the underlying database schema means that it will be less likely you will want to deploy separate changes, but it is still possible.
Finally, regarding the staging server. If you are testing locally you'll want to modify your hosts file to get the host names to point to your local address. Wade Wegner has a post on Running Multiple Websites in a Windows Azure Web Role. Once you deploy to Windows Azure you'd want to change your hosts file back, or comment them out. If you are using the actual idea of the Staging deployment slot you can use the same trick with the hosts file to point to the IP address of the staging deployment when testing.