Viewing CloudFront and Lambda@Edge metrics

You can view operational metrics about your CloudFront distributions and Lambda@Edge functions in the CloudFront console. To view these metrics, see the Monitoring page in the CloudFront console. To view graphs about the activity for a specific CloudFront distribution or Lambda@Edge function, choose one, and then choose to view the metrics.

Viewing the default CloudFront distribution metrics

The following default metrics are included for all CloudFront distributions, at no additional cost:

Requests

The total number of viewer requests received by CloudFront, for all HTTP methods and for both HTTP and HTTPS requests.

Bytes downloaded

The total number of bytes downloaded by viewers for GET, HEAD, and OPTIONS requests.

Bytes uploaded

The total number of bytes that viewers uploaded to your origin with CloudFront, using POST and PUT requests.

4xx error rate

The percentage of all viewer requests for which the response’s HTTP status code is 4xx.

5xx error rate

The percentage of all viewer requests for which the response’s HTTP status code is 5xx.

Total error rate

The percentage of all viewer requests for which the response’s HTTP status code is 4xx or 5xx.

These metrics are shown in graphs for each CloudFront distribution on the Monitoring page in the CloudFront console. On each graph, the totals are displayed at 1-minute granularity. In addition to viewing the graphs, you can also download metrics reports as CSV files.

You can customize the graphs by doing the following:

• To change the time range for the information displayed in the graphs, choose 1h (1 hour), 3h (3 hours), or another range, or specify a custom range.

• To change how often CloudFront updates the information in the graph, choose the down arrow next to the refresh icon, and then choose a refresh interval. The default refresh rate is 1 minute, but you can choose 10 seconds, 2 minutes, or other options.

To view CloudFront graphs in the CloudWatch console, choose Add to dashboard.

Viewing additional CloudFront distribution metrics

In addition to the default metrics, you can enable additional metrics for an additional cost. For more information about the cost, see Estimating cost for the additional CloudFront metrics.

These additional metrics must be enabled for each distribution separately:

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.

Origin latency

The total time spent from when CloudFront receives a request to when it starts providing a response to the network (not the viewer), for requests that are served from the origin, not the CloudFront cache. This is also known as first byte latency, or time-to-first-byte.

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 all of the following error codes: 401, 403, 404, 502, 503, and 504.

To enable additional metrics

1. Sign in to the AWS Management Console and open the Monitoring page in the CloudFront console.

2. Choose the distribution to enable additional metrics for, and then choose View distribution metrics.

3. Choose Enable additional metrics.

4. In the Enable additional metrics window, choose Enable, and then choose Save.

After you enable the additional metrics, they are shown in graphs. On each graph, the totals are displayed at 1-minute granularity. In addition to viewing the graphs, you can also download metrics reports as CSV files.

You can customize the graphs by doing the following:

• To change the time range for the information displayed in the graphs, choose 1h (1 hour), 3h (3 hours), or another range, or specify a custom range.

• To change how often CloudFront updates the information in the graph, choose the down arrow next to the refresh icon, and then choose a refresh interval. The default refresh rate is 1 minute, but you can choose 10 seconds, 2 minutes, or other options.

To view CloudFront graphs in the CloudWatch console, choose Add to dashboard.

Estimating cost for the additional CloudFront metrics

When you enable additional metrics for a distribution, CloudFront sends up to 8 metrics to CloudWatch in the US East (N. Virginia) Region. CloudWatch charges a low, fixed rate for each metric. This rate is charged only once per month, per metric (up to 8 metrics per distribution). This is a fixed rate, so your cost remains the same regardless of the number of requests or responses that the CloudFront distribution receives or sends. For the per-metric rate, see the Amazon CloudWatch pricing page and the CloudWatch pricing calculator. Additional API charges apply when you retrieve the metrics with the CloudWatch API.

Viewing the default Lambda@Edge function metrics

The following default metrics are included for all Lambda@Edge functions, at no additional cost:

• 5xx error rate for Lambda@Edge

• Lambda execution errors

• Lambda invalid responses

• Lambda throttles

These metrics are shown in graphs for each Lambda@Edge function on the Monitoring page in the CloudFront console. The graphs include the number of invocations, errors, throttles, and so on. On each graph, the totals are displayed at 1-minute granularity, grouped by AWS Region.

If you see a spike in errors that you want to investigate, you can choose a function and then view log files by AWS Region, until you determine which function is causing the problems and in which AWS Region. For more information about troubleshooting Lambda@Edge errors, see:

• How to Determine the Type of Failure

• Four Steps for Debugging your Content Delivery on AWS

You can customize the graphs by doing the following:

• To change the time range for the information displayed in the graphs, choose 1h (1 hour), 3h (3 hours), or another range, or specify a custom range.

• To change how often CloudFront updates the information in the graph, choose the down arrow next to the refresh icon, and then choose a refresh interval. The default refresh rate is 1 minute, but you can choose 10 seconds, 2 minutes, or other options.

To view the graphs in the CloudWatch console, choose Add to dashboard. You must use the US East (N. Virginia) Region (us-east-1) to view the graphs in the CloudWatch console.