User Story:

In order to attach IPv6 addresses to the ENI of EC2 instances, the instance type must support IPv6 networking. The following table in AWS doc shows instances with IPv6 address support.

(Optional) In the case of IPv6-only subnet, only nitro-based instance types are supported.

Acceptance Criteria:

Description of criteria:

• Instance type provided to nodes (either overridden by users or defaulted) should be validated to support IPv6 networking.

(optional) Out of Scope:

Detail about what is specifically not being delivered in the story

Engineering Details:

• Default instance m6i.xlarge is supported. However, for bootstrap node, the default i3.large (UPI), which is not Nitro-based. We need to find other alternatives (e.g. i4i.large).
• As of May 22, 2025, the following instance type does not support IPv6 address: C1, M{1,2,3}, T1
• So far, tests with launching EC2 instances on RHEL 9 and RHCOS 9.6 in an ipv6 subnet didn't hit any issue.

This requires/does not require a design proposal.
This requires/does not require a feature gate.