The eight new metrics include:
Cache Hit Rate: The percentage of all cacheable requests for which CloudFront served the content from its cache. HTTP POST and PUT requests, and errors, are not considered cacheable requests. The Cache Hit Rate allows you to determine the proportion of your viewer requests that are served from CloudFront edge caches instead of going to your origin servers for content.
Origin Latency: The total time spent in milliseconds from when CloudFront receives a request to when it provides a response to the network (not the viewer), for requests that are served from the origin, not the CloudFront cache. Origin Latency allows you to monitor the performance of your origin server.
Error Rate by status code: The percentage of all viewer requests for which the response’s HTTP status code is a particular code in the 4xx or 5xx range. This metric is available for the following error codes: 401, 403, 404, 502, 503, and 504. The Error Rate metric allows you to identify the specific type of HTTP status code behind the 4xx or 5xx errors.
These new metrics can now be enabled in the monitoring page of your CloudFront console, standard CloudWatch rates apply. Additional details on how to enable these metrics are available at Viewing Additional CloudFront Distribution Metrics.