The Amazon EC2 Instance Metadata Service, Amazon Time Sync Service, and Amazon VPC DNS server can now be accessed over IPv6 endpoints by instances built on the Nitro System. These local instance services have IPv6 addresses that can be accessed from your Amazon EC2 instances. These IPv6 endpoints use Unique Local Addresses (ULA); IPv6 for local instance services is useful for running software and containers in an IPv6-only single stack configuration. Additionally, if you are starting your transition to IPv6 in a dual-stack environment, the endpoints for the Instance Metadata Service, Amazon Time Sync Service, and Amazon VPC DNS are available over both IPv4 and IPv6.
Source:: Amazon AWS