HIGH
Source
Trivy
ID
AVD-GCP-0053

GKE Control Plane should not be publicly accessible

The GKE control plane is exposed to the public internet by default.

Impact

Follow the appropriate remediation steps below to resolve the issue.

Use private nodes and master authorised networks to prevent exposure

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resource "google_service_account" "default" {
  account_id   = "service-account-id"
  display_name = "Service Account"
}

resource "google_container_cluster" "primary" {
  name     = "my-gke-cluster"
  location = "us-central1"

  # We can't create a cluster with no node pool defined, but we want to only use
  # separately managed node pools. So we create the smallest possible default
  # node pool and immediately delete it.
  remove_default_node_pool = true
  initial_node_count       = 1
  master_authorized_networks_config {
    cidr_blocks {
      cidr_block   = "10.10.128.0/24"
      display_name = "internal"
    }
  }
}

resource "google_container_node_pool" "primary_preemptible_nodes" {
  name       = "my-node-pool"
  location   = "us-central1"
  cluster    = google_container_cluster.primary.name
  node_count = 1

  node_config {
    preemptible  = true
    machine_type = "e2-medium"

    # Google recommends custom service accounts that have cloud-platform scope and permissions granted via IAM Roles.
    service_account = google_service_account.default.email
    oauth_scopes = [
      "https://www.googleapis.com/auth/cloud-platform"
    ]
  }
}