Comment 4 for bug 1982987

So the original implementation on Azure didn't have zones. They had a different concept called Availability Sets, which was more the inverse (everything within one Availability Set would not be taken out simultaneously, vs everything in one Availability Zone goes down in the zone goes down).

Which meant that the original tracking definitely didn't want to pass the Set down as a Zone. However, I do believe with newer ARM logic on Azure (and within Juju) we did switch to a Zone based model, but it seems while the provisioner knows about it, we didn't actually add tracking for it.

Because of a different history for how Azure tracks this information, it is quite a bit more of an issue to start passing it through.