Application Health Extension, a health monitoring service used for managing and upgrading your scale sets, has rolled out two new health states (“Initializing”, “Unknown”) for detailed health reporting using Rich Health States.
New “Initializing” and “Unknown” states will allow you to have more control and flexibility over when instance repairs and rolling upgrades are performed on the scale set.
Rich Health States also allows you to report an “Unhealthy” status by returning a 2xx probe response code with an expected probe response body using HTTP/HTTPs protocol. This allows you to mark VMs that are reachable but are still be considered to be unhealthy.
To learn more, visit: Use Application Health extension with Azure Virtual Machine Scale Sets – Azure Virtual Machine Scale Sets | Microsoft Learn