What information do I give AWS Support to diagnose CloudFront web distribution latency issues?

Resolution

Note: You must have a Developer, Business, or Enterprise Support plan to open a technical support case.

Prepare the following information:

1.    Gather the Amazon CloudFront request IDs for the requests with latency issues. Find the request IDs in one of the following ways:
From the X-Amz-Cf-Id HTTP response header returned by CloudFront. Use a utility such as cURL to retrieve the response header.
-or-
From the CloudFront access log. The request ID is in field number 15 of a web distribution log file.

2.    Measure how long it takes to download the object from CloudFront. Also, measure how long it takes to download the object directly from the origin. Then, get the time difference between the two download methods.

To get this information, use a cURL command similar to the following:

curl -v -L --output /dev/null --silent --show-error --write-out 'lookup: %{time_namelookup}\nconnect: %{time_connect}\nappconnect: %{time_appconnect}\npretransfer: %{time_pretransfer}\nredirect: %{time_redirect}\nstarttransfer: %{time_starttransfer}\ntotal: %{time_total}\n' '<CloudFront-DNS or origin-endpoint>'

If the issue can be reproduced by a browser, collect the related HAR file.

3.    Gather the IP address from your DNS resolver for latency issues with a specific address. For instructions on how to find the public IP address of the DNS resolver, see How can I determine if my public DNS resolver supports the EDNS Client Subnet (ECS) extension?

4.    Collect the TCP Traceroute or MTR reports for the CloudFront DNS or IP and the origin endpoint. For example, your endpoint might be in Amazon Elastic Compute Cloud (Amazon EC2) or an Application Load Balancer.

To get the MTR report, run the following command:

mtr -rwzn <CloudFront-DNS or origin-endpoint>

Related information

Request and response behavior

How do I troubleshoot and reduce increased latency from CloudFront?