Real-time Monitoring in Azure Front Door

Azure Front Door is integrated with Azure Monitor and has 11 metrics to help monitor Azure Front Door in real-time to track, troubleshoot, and debug issues.

Azure Front Door measures and sends its metrics in 60-second intervals. The metrics can take up to 3 mins to appear in the portal. Metrics can be displayed in charts or grid of your choice and are accessible via portal, PowerShell, CLI, and API. For more information, see Azure Monitor metrics.

The default metrics are free of charge. You can enable additional metrics for an extra cost.

You can configure alerts for each metric such as a threshold for 4XXErrorRate or 5XXErrorRate. When the error rate exceeds the threshold, it will trigger an alert as configured. For more information, see Create, view, and manage metric alerts using Azure Monitor.

Metrics supported in Azure Front Door

Metrics Description Dimensions
Bytes Hit ratio The percentage of egress from AFD cache, computed against the total egress. 
Byte Hit Ratio = (egress from edge - egress from origin)/egress from edge.
Scenarios excluded in bytes hit ratio calculation:
1. You explicitly configure no cache either through Rules Engine or Query String caching behavior.
2. You explicitly configure cache-control directive with no-store or private cache.
3. Byte hit ratio can be low if most of the traffic is forwarded to origin rather than served from caching based on your configurations or scenarios.
Endpoint
RequestCount The number of client requests served by CDN. Endpoint, client country, client region, HTTP status, HTTP status group
ResponseSize The number of bytes sent as responses from Front Door to clients. Endpoint, client country, client region, HTTP status, HTTP status group
TotalLatency The total time from the client request received by CDN until the last response byte send from CDN to client. Endpoint, client country, client region, HTTP status, HTTP status group
RequestSize The number of bytes sent as requests from clients to AFD. Endpoint, client country, client region, HTTP status, HTTP status group
4XX % ErrorRate The percentage of all the client requests for which the response status code is 4XX. Endpoint, Client Country, Client Region
5XX % ErrorRate The percentage of all the client requests for which the response status code is 5XX. Endpoint, Client Country, Client Region
OriginRequestCount The number of requests sent from AFD to origin Endpoint, Origin, HTTP status, HTTP status group
OriginLatency The time calculated from when the request was sent by AFD edge to the backend until AFD received the last response byte from the backend. Endpoint, Origin
OriginHealth% The percentage of successful health probes from AFD to origin. Origin, Origin Group
WAF request count Matched WAF request. Action, rule name, Policy Name

Note

If a request to the the origin timeout, the value for HttpStatusCode dimension will be 0.

Access Metrics in Azure portal

  1. From the Azure portal menu, select All Resources >> <your-AFD-profile>.

  2. Under Monitoring, select Metrics:

  3. In Metrics, select the metric to add:

    Screenshot of metrics page.

  4. Select Add filter to add a filter:

    Screenshot of adding filters to metrics.

  5. Select Apply splitting to split data by different dimensions:

    Screenshot of adding dimensions to metrics.

  6. Select New chart to add a new chart:

Configure Alerts in Azure portal

  1. Set up alerts on Azure Front Door Standard/Premium (Preview) by selecting Monitoring >> Alerts.

  2. Select New alert rule for metrics listed in Metrics section.

Alert will be charged based on Azure Monitor. For more information about alerts, see Azure Monitor alerts.

Next steps