K8s node local dns cache remediation

Triage and Remediation

Remediation

Using Console

Using CLI

To remediate the misconfiguration “Cluster Should Use Node Local DNS Cache” in GCP using GCP CLI, follow these steps:

Open the Cloud Shell in GCP Console.
Run the following command to get the list of clusters in your project:

gcloud container clusters list

Identify the cluster that needs to be remediated and run the following command to get the cluster’s credentials:

gcloud container clusters get-credentials <cluster-name> --zone <zone> --project <project-id>

Once you have the credentials, run the following command to update the cluster configuration:

gcloud container clusters update <cluster-name> --zone <zone> --project <project-id> --enable-dns-cache

This command enables the node local DNS cache for the specified cluster.

Verify that the configuration has been updated by running the following command:

gcloud container clusters describe <cluster-name> --zone <zone> --project <project-id> | grep dnsCacheConfig

This command should return the following output, indicating that the node local DNS cache is enabled:

dnsCacheConfig:
  enabled: true

By following these steps, you have successfully remediated the misconfiguration “Cluster Should Use Node Local DNS Cache” for your GCP cluster using GCP CLI.

Using Python

To remediate the misconfiguration “Cluster Should Use Node Local DNS Cache” in GCP using Python, you can follow the below steps:Step 1: Install the necessary Python packages - google-auth and google-api-python-client.

pip install google-auth google-auth-oauthlib google-auth-httplib2 google-api-python-client

Step 2: Authenticate with GCP using a service account key file.

from google.oauth2 import service_account

credentials = service_account.Credentials.from_service_account_file('<path_to_service_account_key_file>')

Step 3: Enable the “Cloud DNS API” for the project.

from googleapiclient.discovery import build

dns_service = build('dns', 'v1', credentials=credentials)

project_id = '<your_project_id>' # Replace with your GCP project ID

dns_service.projects().get(project=project_id).execute()

Step 4: Create a new DNS policy with node-local caching enabled.

policy_body = {
    "alternativeNameServerConfig": {
      "kind": "dns#policyAlternativeNameServerConfig",
      "targetNameServers": [
        {
          "forwardingPath": "default",
          "ipv4Address": "127.0.0.1",
          "kind": "dns#policyAlternativeNameServerConfigTargetNameServer",
          "networkUrl": "https://www.googleapis.com/compute/v1/projects/<your_project_id>/global/networks/default"
        }
      ]
    },
    "description": "Node-local DNS caching enabled policy",
    "enableInboundForwarding": False,
    "enableLogging": False,
    "id": "<your_policy_id>", # Replace with a unique ID for the policy
    "kind": "dns#policy",
    "name": "node-local-dns-caching-policy",
    "networks": [
      {
        "kind": "dns#policyNetwork",
        "networkUrl": "https://www.googleapis.com/compute/v1/projects/<your_project_id>/global/networks/default"
      }
    ],
    "rules": [
      {
        "action": "allow",
        "description": "Allow all DNS queries",
        "kind": "dns#policyRule",
        "match": {
          "kind": "dns#policyRuleCriteriaMatch",
          "queryNamePattern": ".*"
        }
      }
    ],
    "targetNameServers": [
      {
        "forwardingPath": "default",
        "ipv4Address": "8.8.8.8",
        "kind": "dns#policyAlternativeNameServerConfigTargetNameServer",
        "networkUrl": "https://www.googleapis.com/compute/v1/projects/<your_project_id>/global/networks/default"
      }
    ],
    "visibility": "private"
}

policy = dns_service.policies().create(project=project_id, body=policy_body).execute()

Step 5: Assign the newly created DNS policy to the cluster.

from googleapiclient.errors import HttpError

cluster_name = '<your_cluster_name>' # Replace with the name of your GKE cluster
zone = '<your_zone>' # Replace with the zone in which your GKE cluster is located

try:
    cluster = container_service.projects().zones().clusters().get(project=project_id, zone=zone, clusterId=cluster_name).execute()
    cluster['nodeConfig']['dnsPolicy'] = 'Policy'
    cluster['nodeConfig']['dnsConfig']['nameServerConfig']['networks'] = [
        {
          "kind": "dns#policyNetwork",
          "policy": policy['id']
        }
    ]
    update_cluster = container_service.projects().zones().clusters().update(project=project_id, zone=zone, clusterId=cluster_name, body=cluster).execute()
    print(f"DNS policy with node-local caching enabled has been successfully assigned to the cluster: {cluster_name}")
except HttpError as e:
    print(f"An error occurred while assigning DNS policy to the cluster: {cluster_name}. Error message: {e}")

With these steps, the misconfiguration “Cluster Should Use Node Local DNS Cache” has been remediated for GCP using Python.

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K8s node local dns cache remediation

Triage and Remediation

Remediation

GCP Introduction

GCP Pricing

GCP Threats

GCP Misconfigurations

Resources

GCP Threats

​Triage and Remediation

​Remediation

Triage and Remediation

Remediation