When code runs inside an AWS Elastic Compute Cloud (EC2) instance, it often needs information about its environment. Instead of hardcoding credentials or configuration files, the instance queries this link-local IP address. Because it is link-local, the traffic never leaves the physical host or travels over the public internet; it is strictly an internal channel between the virtual machine and the hypervisor. The Role of the IAM Security Credentials Endpoint
Despite the availability of IMDSv2 since late 2019, many legacy instances and misconfigured auto-scaling groups still run IMDSv1—leaving the request-url-http-3A-2F-2F169.254.169.254-2Flatest-2Fmeta data-2Fiam-2Fsecurity credentials-2F endpoint wide open. When code runs inside an AWS Elastic Compute
The URL is likely used in the context of an AWS EC2 instance. When an EC2 instance starts, it can access its metadata through a special IP address ( 169.254.169.254 ) without needing any authentication. The metadata service provides information about the instance and, importantly, temporary security credentials that the instance can use to access AWS services. The Role of the IAM Security Credentials Endpoint
If you append an IAM role name (e.g., MyAppRole ), the complete request becomes: The metadata service provides information about the instance