[Enhancement]: aws_launch_template network_interfaces block missing primary_ipv6

[johngmyers]

Description

Allow an AWS launch template to specify that a network interface should make an IPv6 address be primary. An instance must have a primary IPv6 address in order to be able to be an instance target of an IPv6 target group.

Affected Resource(s) and/or Data Source(s)

aws_launch_template

Potential Terraform Configuration

resource "aws_launch_template" "nodes-minimal-ipv6-example-com" {
  block_device_mappings {
    device_name = "/dev/xvda"
    ebs {
      delete_on_termination = true
      encrypted             = true
      iops                  = 3000
      throughput            = 125
      volume_size           = 128
      volume_type           = "gp3"
    }
  }
  iam_instance_profile {
    name = aws_iam_instance_profile.nodes-minimal-ipv6-example-com.id
  }
  image_id      = "ami-12345678"
  instance_type = "t3.medium"
  key_name      = aws_key_pair.kubernetes-minimal-ipv6-example-com-c4a6ed9aa889b9e2c39cd663eb9c7157.id
  lifecycle {
    create_before_destroy = true
  }
  metadata_options {
    http_endpoint               = "enabled"
    http_protocol_ipv6          = "enabled"
    http_put_response_hop_limit = 1
    http_tokens                 = "optional"
  }
  monitoring {
    enabled = false
  }
  name = "nodes.minimal-ipv6.example.com"
  network_interfaces {
    associate_public_ip_address = false
    delete_on_termination       = true
    ipv6_address_count          = 1
    primary_ipv6                = true
    security_groups             = [aws_security_group.nodes-minimal-ipv6-example-com.id]
  }
  tag_specifications {
    resource_type = "instance"
    tags = {
      "KubernetesCluster"                                                          = "minimal-ipv6.example.com"
      "Name"                                                                       = "nodes.minimal-ipv6.example.com"
      "aws-node-termination-handler/managed"                                       = ""
      "k8s.io/cluster-autoscaler/node-template/label/node-role.kubernetes.io/node" = ""
      "k8s.io/role/node"                                                           = "1"
      "kops.k8s.io/instancegroup"                                                  = "nodes"
      "kubernetes.io/cluster/minimal-ipv6.example.com"                             = "owned"
    }
  }
  tag_specifications {
    resource_type = "volume"
    tags = {
      "KubernetesCluster"                                                          = "minimal-ipv6.example.com"
      "Name"                                                                       = "nodes.minimal-ipv6.example.com"
      "aws-node-termination-handler/managed"                                       = ""
      "k8s.io/cluster-autoscaler/node-template/label/node-role.kubernetes.io/node" = ""
      "k8s.io/role/node"                                                           = "1"
      "kops.k8s.io/instancegroup"                                                  = "nodes"
      "kubernetes.io/cluster/minimal-ipv6.example.com"                             = "owned"
    }
  }
  tags = {
    "KubernetesCluster"                                                          = "minimal-ipv6.example.com"
    "Name"                                                                       = "nodes.minimal-ipv6.example.com"
    "aws-node-termination-handler/managed"                                       = ""
    "k8s.io/cluster-autoscaler/node-template/label/node-role.kubernetes.io/node" = ""
    "k8s.io/role/node"                                                           = "1"
    "kops.k8s.io/instancegroup"                                                  = "nodes"
    "kubernetes.io/cluster/minimal-ipv6.example.com"                             = "owned"
  }
  user_data = filebase64("${path.module}/data/aws_launch_template_nodes.minimal-ipv6.example.com_user_data")
}

References

https://aws.amazon.com/about-aws/whats-new/2023/08/amazon-vpc-primary-ipv6-address-elastic-interface/

Would you like to implement a fix?

None

[github-actions]

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[oliviassss]

@johngmyers, thanks for opening this issue. I'm not familiar with terraform, but just wondering do we also need to update the eks-cluster template for the missing field to enable primary ipv6? Or it will respect the value in aws_launch_template
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/eks_cluster

[johngmyers]

@oliviassss This shouldn't affect the aws_eks_cluster resource itself. It's just that the launch template for any node in the cluster will need this setting in order for it to be an instance target of an IPv6 target group. (Or something else would have to promote one of the instance's IPv6 addresses to primary.)