User Story:

When installing a dualstack cluster, the cluster-etcd-operator is expecting an IPv6 machine network entry in the cluster-config ConfigMap, which contains the install-config content. However, for AWS, the IPv6 machine network is not available until the VPC becomes ready.

Thus, we must edit the ignition content to inject the VPC IPv6 CIDR into the cluster-config ConfigMap at file manifests/cluster-config.yaml post infra-ready install phase.

Acceptance Criteria:

Description of criteria:

• The cluster-config ConfigMap has the IPv6 machine network (from VPC IPv6 CIDR).

(optional) Out of Scope:

Detail about what is specifically not being delivered in the story

Engineering Details:

• https://github.com/openshift/cluster-etcd-operator/blob/8feba314db28004600cb8e6bc525305aeb44ffdf/pkg/cmd/render/render.go#L540 
• See commit: https://github.com/openshift/installer/pull/9930/changes/61754ea6001cb62cfe39cc612b944dce9d9171a5#diff-3dd584379ab8bde1b048ab4b9e75547343afe426d559019f1118dbd60b8c92ae 

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