Migrate fully to AWS SDK V2

[mattl-netflix]

• d61cfb8 2026-06-15 | Merge IS3Credential and ICredential now that their functionality is the same. (HEAD -> feature/imdsv2_testing, origin/feature/imdsv2_testing) [Matt Lehman]
• 498985b 2026-06-14 | Migrate all AWS credential usage to SDK V2. Clean up EC2RoleAssumption logic. [Matt Lehman]
• 9aef6dd 2026-06-14 | Remove cross-account support. [Matt Lehman]
• 7e578f5 2026-06-14 | Migrate AWSInstanceInfo to use SDK V2. [Matt Lehman]
• 92d8ca9 2026-06-13 | Remove SecurityGroupAdmin. [Matt Lehman]
• d5aee05 2026-06-11 | Remove SNS notification functionality. No one is listening. [Matt Lehman]%

[JLu76]

Claude:

1. IMDSv2-Only Enforcement: The current implementation allows fallback to IMDSv1. For full security benefits, you should:
   • Configure the SDK to enforce IMDSv2-only mode, OR
   • Set EC2 instance metadata options to HttpTokens=required (instance-level enforcement)
2. No Tests: I didn't find any tests specifically validating IMDSv2 behavior. Consider adding:
   • Integration tests that verify metadata retrieval works
   • Tests that validate IMDSv2 token-based requests
3. Configuration Options: The code uses Ec2MetadataClient.create() with default settings. You might want to explicitly configure:

  Ec2MetadataClient.builder()                                                                                                                                          
      .endpointMode(EndpointMode.IPV4) // or IPV6                                                                                                                      
      .build()  

For #1, looks like theres no way to control fallback to v1 at the SDK / code level