Error: Kubernetes cluster unreachable: invalid configuration: no configuration has been provided

Problem

I’m managing my k8s deployment using Terraform. I’m trying to change my cluster settings (decreasing the nodes). However when I do this I get an authentication error.

Terraform code

main.tf

terraform {
  # Backend configuration
  cloud {
    organization = "Clipido"
  }

  # Plugins configuration
  required_providers {
    kubectl = {
      source  = "alekc/kubectl"
      version = ">= 2.0.2"
    }

    infisical = {
      source = "infisical/infisical"
    }

    digitalocean = {
      source  = "digitalocean/digitalocean"
      version = "~> 2.0"
    }

    helm = {
      source  = "hashicorp/helm"
      version = "~> 2.0"
    }

    kubernetes = {
      source  = "hashicorp/kubernetes"
      version = "~> 2.0"
    }
  }
}

data "digitalocean_kubernetes_cluster" "clipido" {
  name       = digitalocean_kubernetes_cluster.clipido.name
  depends_on = [digitalocean_kubernetes_cluster.clipido]
}

provider "helm" {
  # Authentication to get into the cluster
  kubernetes {
    host                   = data.digitalocean_kubernetes_cluster.clipido.endpoint
    cluster_ca_certificate = base64decode(data.digitalocean_kubernetes_cluster.clipido.kube_config.0.cluster_ca_certificate)
    token                  = data.digitalocean_kubernetes_cluster.clipido.kube_config.0.token
  }
}

provider "kubernetes" {

  # Authentication to get into the cluster

  host                   = data.digitalocean_kubernetes_cluster.clipido.endpoint
  cluster_ca_certificate = base64decode(data.digitalocean_kubernetes_cluster.clipido.kube_config.0.cluster_ca_certificate)
  token                  = data.digitalocean_kubernetes_cluster.clipido.kube_config.0.token
}

do-kubernetes.tf

resource "digitalocean_kubernetes_cluster" "clipido" {

  name         = "clipido-${var.infisical_env}"
  region       = "ams3"        # `doctl kubernetes options regions`
  version      = "1.27.4-do.0" # `doctl kubernetes options versions`
  auto_upgrade = true

  maintenance_policy {
    start_time = "04:00"
    day        = "sunday"
  }

  node_pool {
    name       = "web"
    size       = "s-1vcpu-2gb" # `doctl kubernetes options sizes`
    auto_scale = true
    min_nodes  = 1
    max_nodes  = 2
    tags       = ["frontend", "web"]

    labels = {
      service  = "frontend"
      priority = "high"
    }
  }
}

resource "digitalocean_project_resources" "assign_kubernetes_to_project" {
  project = digitalocean_project.project.id
  resources = [
    digitalocean_kubernetes_cluster.clipido.urn,
  ]
}

do-network.tf

resource "helm_release" "nginx_ingress-helm" {
  name       = "ingress-nginx"
  repository = "https://kubernetes.github.io/ingress-nginx"
  chart      = "ingress-nginx"
  namespace  = "terraform-clipido-${var.project_env}"
  version    = "4.5.2"
  timeout    = 300

  set {
    name  = "controller.daemonset.useHostPort"
    value = "false"
  }

  set {
    name  = "controller.ingressClassResource.default"
    value = "true"
  }

  set {
    name  = "controller.ingressClassResource.name"
    value = "nginx"
  }

  set {
    name  = "controller.kind"
    value = "DaemonSet"
  }

  set {
    name  = "controller.publishService.enabled"
    value = "true"
  }

  set {
    name  = "controller.resources.requests.memory"
    value = "140Mi"
  }

  set {
    name  = "controller.service.externalTrafficPolicy"
    value = "Local"
  }
}

Terraform plan

Terraform planned the following actions, but then encountered a problem:

  # data.digitalocean_kubernetes_cluster.clipido will be read during apply
  # (depends on a resource or a module with changes pending)
 <= data "digitalocean_kubernetes_cluster" "clipido" {
      + auto_upgrade       = (known after apply)
      + cluster_subnet     = (known after apply)
      + created_at         = (known after apply)
      + endpoint           = (known after apply)
      + ha                 = (known after apply)
      + id                 = (known after apply)
      + ipv4_address       = (known after apply)
      + kube_config        = (sensitive value)
      + maintenance_policy = (known after apply)
      + name               = "clipido-staging"
      + node_pool          = (known after apply)
      + region             = (known after apply)
      + service_subnet     = (known after apply)
      + status             = (known after apply)
      + surge_upgrade      = (known after apply)
      + updated_at         = (known after apply)
      + urn                = (known after apply)
      + version            = (known after apply)
      + vpc_uuid           = (known after apply)
    }

  # digitalocean_kubernetes_cluster.clipido will be updated in-place
  ~ resource "digitalocean_kubernetes_cluster" "clipido" {
        id                               = "60d49a31-xxxx-xxxx-xxxx-xxxxxxxxxx"
        name                             = "clipido-staging"
        tags                             = []
        # (16 unchanged attributes hidden)

      ~ node_pool {
            id                = "60d49a31-xxxx-xxxx-xxxx-xxxxxxxxxx"
          ~ max_nodes         = 3 -> 2
            name              = "web"
            tags              = [
                "frontend",
                "web",
            ]
            # (7 unchanged attributes hidden)
        }

        # (1 unchanged block hidden)
    }

Plan: 0 to add, 1 to change, 0 to destroy.

Changes to Outputs:
  ~ endpoint = "https://60d49a31-xxxx-xxxx-xxxx-xxxxxxxxxx.k8s.ondigitalocean.com" -> (known after apply)
╷
│ Error: Get "http://localhost/api/v1/namespaces/terraform-clipido-staging": dial tcp [::1]:80: connect: connection refused
│
│   with kubernetes_namespace.default,
│   on do-network.tf line 21, in resource "kubernetes_namespace" "default":
│   21: resource "kubernetes_namespace" "default" {
│
╵
╷
│ Error: Kubernetes cluster unreachable: invalid configuration: no configuration has been provided, try setting KUBERNETES_MASTER environment variable
│
│   with helm_release.nginx_ingress-helm,
│   on do-network.tf line 27, in resource "helm_release" "nginx_ingress-helm":
│   27: resource "helm_release" "nginx_ingress-helm" {
│
╵
Operation failed: failed running terraform plan (exit 1)