fix: Use cluster ID when present, otherwise use cluster name for id

[bryantbiggs]

Description

Relations

Closes #27560

References

The Cluster type has an Id attribute that is (currently) populated when deploying EKS on Outpost (local cluster), but is null for clusters deployed into AWS cloud. Ref https://docs.aws.amazon.com/sdk-for-go/api/service/eks/#Cluster

This poses a challenge when using the cluster ID for authentication to the cluster API server when using the exec method on providers such as the Kubernetes provider due to the fact that the ID passed is actually the name and not the true ID:

provider "kubernetes" {
  host                   = aws_eks_cluster.test.endpoint
  cluster_ca_certificate = base64decode(aws_eks_cluster.this[0].certificate_authority[0].data)

  exec {
    api_version = "client.authentication.k8s.io/v1beta1"
    command     = "aws"
    args        = ["eks", "get-token", "--cluster-id", aws_eks_cluster.this.id, "--region", data.aws_region.current.name]
  }
}

Or when using the aws_eks_cluster_auth data source since the data source is again using the cluster name as the ID internally:

provider "kubernetes" {
  host                   = aws_eks_cluster.test.endpoint
  cluster_ca_certificate = base64decode(aws_eks_cluster.this[0].certificate_authority[0].data)
  token                  = data.aws_eks_cluster_auth.this.token
}

data "aws_eks_cluster_auth" "this" {
  name = aws_eks_cluster.test.id
}

Output from Acceptance Testing

$ make testacc TESTS=TestAccXXX PKG=ec2

...

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This functionality has been released in v4.45.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

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