We have an application that requires an Azure VM to phone home to our management server (outside Azure) and identify itself.
1. Is there any attribute that uniquely identifies a VM in all of Azure? I thought at first the Deployment ID could serve this purpose. However, it appears that if you deploy two VMs with the same cloud service name, they get the same Deployment ID. Similarly, it appears the DNS Name is not unique because two VMs get the same DNS Name if they have the same cloud service name. The public IP address is apparently unique, but not persistent. I don't think it can serve our purpose because it's subject to change and you don't know what it's going to be in advance.
2. If there is such a unique identifier, is it stored locally on the VM somewhere where it can be queried by an application on the VM, that is, without doing a query across the Internet?
3. Is there any way, when deploying a VM from an image, to pass in data to the resulting VM? That is, could we make up our own unique identifier and pass it to the VM during deployment?
Thanks for your help!
Joseph