The Azure naming convention documentation reminds you that Azure virtual machines have two names:
Virtual machine resource name: this is the Azure identifier for the virtual machine resource. It is the name you use to reference the virtual machine in any Azure automation. It cannot be changed.
Computer hostname: the runtime computer name of the in-guest operating system. The computer name can be changed at will.
If you create a VM using the Azure portal, for simplicity we use the same name for both the virtual machine resource name, and the computer hostname. You could always log into the VM and change the hostname; however, the portal only showed the virtual machine resource name. With this change, the portal now exposes both the virtual machine name, and the computer hostname in the VM overview blade. We also added more detailed operation system version info. These properties are visible for running virtual machines that have a healthy running VMAgent installed.