Spanner Database Backup Should Be Encrypted With Customer Managed Keys

Using Console

To remediate the misconfiguration of Spanner Database Backup not being encrypted with customer-managed keys in GCP, follow these steps:

Go to the GCP Console and navigate to the Spanner instance whose backup you want to encrypt.
Click on the “Backups” tab in the left-hand menu.
Find the backup that needs to be encrypted and click on its name.
Click on the “Encryption” tab in the top menu.
Click on the “Edit” button.
Select “Customer-managed key” from the “Encryption type” dropdown.
Choose the appropriate key from the “Key name” dropdown.
Click on the “Save” button to save the changes.
Verify that the backup is now encrypted with the customer-managed key by checking the “Encryption” tab.
Repeat these steps for any other Spanner backups that need to be encrypted with customer-managed keys.

By following these steps, you can remediate the misconfiguration of Spanner Database Backup not being encrypted with customer-managed keys in GCP.

Using CLI

To remediate this misconfiguration in GCP, you can follow these steps using GCP CLI:

First, you need to create a new key ring and key using the following command:

gcloud kms keyrings create [KEY_RING_NAME] --location [LOCATION]
gcloud kms keys create [KEY_NAME] --location [LOCATION] --keyring [KEY_RING_NAME] --purpose encryption

Replace [KEY_RING_NAME], [LOCATION], and [KEY_NAME] with your own values.

Next, you need to grant the Cloud Spanner service account permission to use the key by adding the cloudkms.cryptoKeyEncrypterDecrypter role to the service account. You can use the following command:
gcloud projects add-iam-policy-binding [PROJECT_ID] --member serviceAccount:[SERVICE_ACCOUNT_EMAIL] --role roles/cloudkms.cryptoKeyEncrypterDecrypter --condition=None
Replace [PROJECT_ID] and [SERVICE_ACCOUNT_EMAIL] with your own values.
Now, you need to configure Cloud Spanner to use the customer-managed encryption key by updating the backup configuration. You can use the following command:
gcloud spanner backups update [BACKUP_ID] --encryption-config kms-key-name=[KEY_NAME] --encryption-type customer-managed
Replace [BACKUP_ID] and [KEY_NAME] with your own values.
Finally, you need to verify that the backup configuration has been updated successfully by running the following command:
gcloud spanner backups describe [BACKUP_ID]
This command should return the details of the backup configuration, including the encryption configuration.

By following these steps, you can remediate the misconfiguration and ensure that your Spanner database backups are encrypted with customer-managed keys in GCP.

Using Python

To remediate the misconfiguration “Spanner Database Backup Should Be Encrypted With Customer Managed Keys” for GCP using Python, you can follow these steps:

Create a Customer Managed Encryption Key (CMEK) in Google Cloud KMS. This key will be used to encrypt the backups. You can use the following code to create a CMEK:

from google.cloud import kms_v1
from google.cloud.kms_v1 import enums

client = kms_v1.KeyManagementServiceClient()

# Set the Key Ring and Key ID
key_ring_id = 'your-key-ring-id'
key_id = 'your-key-id'

# Set the Key Purpose
purpose = enums.CryptoKey.CryptoKeyPurpose.ENCRYPT_DECRYPT

# Create the Key
parent = client.key_ring_path('[PROJECT]', key_ring_id)
response = client.create_crypto_key(parent, key_id, {'purpose': purpose})
print('Created key: {}'.format(response.name))

Enable backup encryption for your Spanner instance. You can use the following code to enable backup encryption:

from google.cloud import spanner_admin_database_v1

# Set the instance and database IDs
instance_id = 'your-instance-id'
database_id = 'your-database-id'

# Set the backup configuration
backup_config = {
    'encryption_config': {
        'kms_key_name': 'projects/[PROJECT]/locations/[LOCATION]/keyRings/[KEYRING]/cryptoKeys/[KEY]'
    }
}

# Update the backup configuration
database_admin_client = spanner_admin_database_v1.DatabaseAdminClient()
database_name = database_admin_client.database_path('[PROJECT]', instance_id, database_id)
operation = database_admin_client.update_backup(database_name, backup_config)
print('Backup encryption enabled: {}'.format(operation))

Verify that backup encryption is enabled for your Spanner instance. You can use the following code to verify backup encryption:

from google.cloud import spanner_admin_database_v1

# Set the instance and database IDs
instance_id = 'your-instance-id'
database_id = 'your-database-id'

# Get the database backup configuration
database_admin_client = spanner_admin_database_v1.DatabaseAdminClient()
database_name = database_admin_client.database_path('[PROJECT]', instance_id, database_id)
backup_info = database_admin_client.get_backup_info(database_name)
print('Backup encryption enabled: {}'.format(backup_info.encryption_info.encryption_type))

This will ensure that your Spanner database backups are encrypted with a customer-managed encryption key in Google Cloud KMS.

Using Terraform

resource "google_spanner_backup" "SPANNER_BACKUP_NAME" {
  # Replace with your Spanner instance and database details
  instance     = "SPANNER_INSTANCE_ID"          # e.g. "my-spanner-instance"
  database     = "SPANNER_DATABASE_NAME"        # e.g. "db1"
  backup_id    = "SPANNER_BACKUP_ID"            # e.g. "db1-backup-20240727"
  expire_time  = "2026-12-31T23:59:59Z"

  # Use a customer-managed Cloud KMS key for encryption
  kms_key_name = "projects/PROJECT_ID/locations/LOCATION/keyRings/KEY_RING/cryptoKeys/CRYPTO_KEY"
  # - PROJECT_ID:     KMS project (can be different from Spanner project if IAM allows)
  # - LOCATION:       Must match the Spanner instance / database region
  # - KEY_RING:       Existing key ring name
  # - CRYPTO_KEY:     Existing key name
}

Using a KMS key for an existing backup requires creating a new backup; Terraform will show this as google_spanner_backup.SPANNER_BACKUP_NAME being replaced, which deletes the old backup and creates a new CMEK‑encrypted one (backups are immutable).For verification, terraform plan should show kms_key_name being added (or changed) on the google_spanner_backup resource, and if it was previously unencrypted or using Google‑managed keys, the resource will be marked for replacement.

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