How to use same terraform code for both kubernetes clusters Oracle (OKE) and AWS (EKS)?

Question

I want to use same terraform code for both kubernetes clusters oracle (OKE) and AWS (EKS) and install the argocd helm chart on it, I given my code below for your reference, now the problem I am facing now, if I set k8s_cluster_type to "eks", so everything works fine but when I set the k8s_cluster_type to "oke", it fails with given below error,

I get this error:-

│ Error: error reading EKS Cluster (oh-appb-01): couldn't find resource
│ 
│   with data.aws_eks_cluster.eks,
│   on main.tf line 137, in data "aws_eks_cluster" "eks":
│  137: data "aws_eks_cluster" "eks" {
│ 

What I want to do:-

In case if I give eks_cluster_name (dummy_cluster_name) or eks cluster doesn't exist, still this code should run as same like oke, because if I assign dummy_name oke cluster or oke cluster doens't exist and input variable k8s_cluster_type to "eks" this terraform runs successfully, Could you suggest, how can I use same terraform for both kubernetes cluster to install argocd helm chart

locals {
  argocd_ns = "argocd"


  kubeconfig_str = var.k8s_cluster_type == "oke" ? data.oci_containerengine_cluster_kube_config.k8s.content : data.template_file.temp_kubeconfig_eks.rendered
  kubeconfig = yamldecode( local.kubeconfig_str )

  exec_cli = var.k8s_cluster_type == "oke"? "oci" : "aws"

  cluster_cert = var.k8s_cluster_type == "oke" ? base64decode(local.kubeconfig["clusters"][0]["cluster"]["certificate-authority-data"]) : base64decode(data.aws_eks_cluster.eks.certificate_authority[0].data)
  cluster_endpoint = var.k8s_cluster_type == "oke" ? local.kubeconfig["clusters"][0]["cluster"]["server"] : data.aws_eks_cluster.eks.endpoint


  exec_args_oke = [
    local.kubeconfig["users"][0]["user"]["exec"]["args"][0],
    local.kubeconfig["users"][0]["user"]["exec"]["args"][1],
    local.kubeconfig["users"][0]["user"]["exec"]["args"][2],
    local.kubeconfig["users"][0]["user"]["exec"]["args"][3],
    local.kubeconfig["users"][0]["user"]["exec"]["args"][4],
    local.kubeconfig["users"][0]["user"]["exec"]["args"][5],
    local.kubeconfig["users"][0]["user"]["exec"]["args"][6]
  ]

  exec_args_eks = ["eks", "get-token", "--cluster-name", var.eks_cluster_name]
  exec_args = var.k8s_cluster_type == "oke" ? local.exec_args_oke : local.exec_args_eks



}




data "oci_containerengine_cluster_kube_config" "k8s" {
  #count = var.k8s_cluster_type == "oke" ? 1 : 0
  cluster_id = var.k8s_cluster_id
}


resource "local_file" "temp_kubeconfig" {
  count = var.k8s_cluster_type == "oke" ? 1 : 0
  content  = local.kubeconfig_str
  filename = "${path.module}/kubeconfig_temp"
}

resource "local_file" "temp_kubeconfig_eks" {
  count = var.k8s_cluster_type == "oke" ? 0 : 1
  content  = data.template_file.temp_kubeconfig_eks.rendered
  filename = "${path.module}/kubeconfig_temp"
}


resource "kubernetes_namespace" "argocd" {
  metadata {
    name = local.argocd_ns
  }
}

resource "kubernetes_secret" "root_repo" {
  depends_on = [kubernetes_namespace.argocd]
  metadata {
    name = var.argocd_root_repo.name
    namespace = local.argocd_ns
    labels = {
      "argocd.argoproj.io/secret-type" = "repository"
    }
  }
  data = {
    url = var.argocd_root_repo.url
    name = var.argocd_root_repo.name
    password = var.argocd_root_repo_token
    username = var.argocd_root_repo.name

  }
}


data "template_file" "argocd-helm-values-override" {
  template = file("${path.module}/templates/argocd-helm-values-override.tpl")
  vars = {
    argocd_ns = local.argocd_ns
    repo_url = var.argocd_root_repo.url
    repo_path = var.argocd_root_repo.path
    repo_revision = var.argocd_root_repo.revision
  }
}

resource "helm_release" "argocd" {
  depends_on = [kubernetes_namespace.argocd, kubernetes_secret.root_repo ]
  version    = var.argocd_release.chart_version
  name       = var.argocd_release.release_name
  chart      = var.argocd_release.chart_name
  repository = var.argocd_release.chart_repo
  namespace  = local.argocd_ns
  values = [
    data.template_file.argocd-helm-values-override.rendered
  ]
}


data "template_file" "temp_kubeconfig_eks" {
  count = var.k8s_cluster_type == "oke" ? 0 : 1
  template = file("${path.module}/templates/kubeconfig_eks.tpl")
  vars = {
    cluster_url = data.aws_eks_cluster.eks.endpoint
    cluster_region = var.region
    cluster_cert_authority_data = data.aws_eks_cluster.eks.certificate_authority.0.data
    cluster_name = var.eks_cluster_name
  }
}

provider "kubernetes" {
  cluster_ca_certificate = local.cluster_cert
  host                   = local.cluster_endpoint
  exec {
    api_version = "client.authentication.k8s.io/v1beta1"
    command     = local.exec_cli
    args        = local.exec_args
  }
}
provider "helm" {
  kubernetes {
    cluster_ca_certificate = local.cluster_cert
    host                   = local.cluster_endpoint
    exec {
      api_version = "client.authentication.k8s.io/v1beta1"
      command     = local.exec_cli
      args        = local.exec_args
    }
  }
}


data "aws_eks_cluster" "eks" {
  #count = var.k8s_cluster_type == "oke" ? 0 : 1
  name = var.eks_cluster_name
}

data "aws_eks_cluster_auth" "eks" {
  #count = var.k8s_cluster_type == "oke" ? 0 : 1
  name = var.eks_cluster_name 
}

*.tfvars file:-

8s_cluster_id ="ocid1.cluster.oc1.xxx.xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
k8s_cluster_type = "oke"

argocd_root_repo = {
  name = "argocd-xxxx-xxxx-config",
  url = "https://github.com/xxxxx/xxxx/argocd-xxxx-xxxx-config",
  path = "clusters/localsand1/apps",
  revision = "master"
}

region = "us-east-1"
eks_cluster_name = "oh-appb-01"

Answer 1

You have commented out the count check of the aws_eks_cluster.eks data source that would make the data source conditional, depending on the k8s_cluster_type setting. Uncommenting the count argument should make it skip the data source and not complain about it not being found.

data "aws_eks_cluster" "eks" {
  count = var.k8s_cluster_type == "oke" ? 0 : 1
  name  = var.eks_cluster_name
}