Azure Front Door is a global, scalable service that acts as a content delivery network (CDN) and application load balancer to improve application performance and availability. The way you expose application on Azure FD is by creating origins. For each origin you have to add one or more origins. When configuring the origin you have the option to configure health probe. The health probe makes sure the origins are up. If an origin is not up it will traffic will not be sent to it. The results from the health probes is visible via OriginHealthPercentage metric. Now let’s have a closer look to metric OriginHealthPercentage as the results from it might be a little bit confusing, especially when you send the metric to Log Analytics workspace and viewed there.