Azure Web App switches server automatically?

We have a website running in azure as a Web App. Only 1 instance of the site is running. We are seeing regular downtimes for the site, and wondering why.

We use Elmah to log exceptions, and before a downtime occurs we can't see any relevant or critical errors. What we do see however, is that AFTER the downtime, the site is back up but on another server. (We can see this because the hostname of the server changes, and when an exception is thrown we can see in Elmah from which server it originated.) Small example:

Server: X
Some small Exception thrown on server X, shows up in Elmah
site goes down
Site comes back up
Server: Y
Some small exception thrown on server Y, shows up in Elmah

Now I know that azure has Rapid Fail Protection and Auto Healing, but in our scenario, I cant tell the difference between our site

a) moving to another server and going down (because there is only 1 instance)

b) rapid fail protection or auto healing kicking in

If it's option a: does anyone know based on what azure moves sites?

if it's option b: does anyone know how I can determine why/how something triggered a rapid fail protection or auto healing kick in?

via Chebli Mohamed