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Cloud CDN Regional Backend Services Should Have Session

More Info:​

Cloud CDN regional backend services should have session affinity enabled.

Risk Level​

Medium

Address​

Operational Maturity, Performance Efficiency, Security

Compliance Standards​

  • Cloudanix Best Practice

Triage and Remediation​

Remediation​

Using Console

To remediate the misconfiguration of "Cloud CDN Regional Backend Services Should Have Session Affinity" for GCP using GCP console, follow the below steps:

  1. Open the Google Cloud Console and navigate to the Cloud CDN page.

  2. In the left-hand navigation menu, select "Backend Services".

  3. Select the Backend Service that you want to configure session affinity for.

  4. Click on the "Edit" button at the top of the page to edit the Backend Service.

  5. Scroll down to the "Session Affinity" section and select "Client IP" from the dropdown menu.

  6. Click on the "Save" button at the bottom of the page to save the changes.

  7. Verify the configuration by checking the "Session Affinity" column in the list of Backend Services. It should now show "Client IP".

By following the above steps, you have successfully remediated the misconfiguration of "Cloud CDN Regional Backend Services Should Have Session Affinity" for GCP using GCP console.

Using CLI

To remediate the misconfiguration "Cloud CDN Regional Backend Services Should Have Session Affinity" in GCP using GCP CLI, please follow the below steps:

  1. Open the Cloud Shell in your GCP console.

  2. Run the following command to list all the backend services:

    gcloud compute backend-services list

  3. Choose the backend service that you want to enable session affinity for and note down its name.

  4. Run the following command to enable session affinity for the chosen backend service:

    gcloud compute backend-services update [BACKEND_SERVICE_NAME] --session-affinity CLIENT_IP

    Note: Replace [BACKEND_SERVICE_NAME] with the name of your backend service.

  5. Verify that session affinity is enabled for the backend service by running the following command:

    gcloud compute backend-services describe [BACKEND_SERVICE_NAME] | grep sessionAffinity

    The output should show "sessionAffinity: CLIENT_IP".

    With these steps, you have successfully remediated the misconfiguration "Cloud CDN Regional Backend Services Should Have Session Affinity" in GCP using GCP CLI.

Using Python

To remediate the misconfiguration of Cloud CDN Regional Backend Services Should Have Session Affinity for GCP using Python, you can follow the below steps:

  1. Open the Cloud Console and go to the Cloud CDN page.
  2. Select the CDN resource that you want to remediate.
  3. In the left navigation menu, select the Backend services option.
  4. Select the backend service that you want to remediate.
  5. In the left navigation menu, select the Session affinity option.
  6. Select the option Enable session affinity.
  7. Click Save to apply the changes.

To perform these steps programmatically using Python, you can use the Google Cloud Client Library for Python. Here's an example code snippet:

from google.cloud import compute_v1

# Replace [PROJECT_ID], [REGION], and [BACKEND_SERVICE_NAME] with the appropriate values
project_id = '[PROJECT_ID]'
region = '[REGION]'
backend_service_name = '[BACKEND_SERVICE_NAME]'

# Create the client object
client = compute_v1.BackendServicesClient()

# Get the backend service object
backend_service = client.get(project=project_id, region=region, backend_service=backend_service_name)

# Enable session affinity
backend_service.session_affinity = compute_v1.BackendServiceSessionAffinity.CLIENT_IP

# Update the backend service
update_mask = compute_v1.field_mask.FieldMask(paths=['session_affinity'])
response = client.update(project=project_id, region=region, backend_service=backend_service_name, backend_service_resource=backend_service, update_mask=update_mask)

This code snippet uses the Google Cloud Client Library for Python to get the backend service object, enable session affinity, and update the backend service. Replace the placeholders [PROJECT_ID], [REGION], and [BACKEND_SERVICE_NAME] with the appropriate values for your environment.

Using Terraform
resource "google_compute_region_backend_service" "CDN_BACKEND_SERVICE" {
  name          = "CDN_BACKEND_SERVICE_NAME"            # replace with your backend service name
  region        = "BACKEND_REGION"                      # e.g. "us-central1"
  protocol      = "HTTP"
  load_balancing_scheme = "EXTERNAL_MANAGED"
  enable_cdn    = true

  # other required arguments such as backends, health_checks, etc.
  # backends      = [...]
  # health_checks = [google_compute_health_check.example.self_link]

  # Enable session affinity for the regional Cloud CDN backend service
  session_affinity = "CLIENT_IP"

  project = "GCP_PROJECT_ID"                            # replace with your project ID
}

This change is in-place and does not force replacement of the backend service; it updates the existing service to use client IP–based session affinity.

After updating your Terraform, terraform plan should show a single ~ (update in-place) on the google_compute_region_backend_service resource with session_affinity changing from its previous value (often "NONE") to "CLIENT_IP".

Additional Reading:​