To remediate the misconfiguration “KMS Key Should Have Unique Key In DB Tier” in GCP using GCP CLI, you can follow the below steps:

1. Identify the KMS key associated with the DB tier. You can do this by running the following command:

   gcloud kms keys list --location=<location> --keyring=<keyring>
   

   Replace <location> and <keyring> with the location and keyring name where the KMS key is stored.

2. Check if the KMS key is associated with the DB tier by running the following command:

   gcloud sql instances describe <instance-name> --format=json | jq '.settings.settingsVersion' | grep -q kmsKeyName
   

   Replace <instance-name> with the name of the Cloud SQL instance.

3. If the KMS key is associated with the DB tier, create a new KMS key and associate it with the DB tier. You can do this by running the following commands:

   gcloud kms keyrings create <keyring-name> --location=<location>
   gcloud kms keys create <kms-key-name> --location=<location> --keyring=<keyring-name> --purpose=encryption
   gcloud sql instances patch <instance-name> --backup-configuration kms-key-name=projects/<project-id>/locations/<location>/keyRings/<keyring-name>/cryptoKeys/<kms-key-name>
   

   Replace <keyring-name>, <location>, <kms-key-name>, <instance-name>, and <project-id> with appropriate values.

4. Verify that the new KMS key is associated with the DB tier by running the following command:

   gcloud sql instances describe <instance-name> --format=json | jq '.settings.settingsVersion' | grep -q <kms-key-name>
   

   Replace <instance-name> and <kms-key-name> with appropriate values.

Once you have completed the above steps, the misconfiguration “KMS Key Should Have Unique Key In DB Tier” will be remediated for GCP.

To remediate the KMS Key Should Have Unique Key In DB Tier misconfiguration in GCP using Python, you can follow these steps:

1. First, you need to identify the KMS key used in the DB tier. You can do this by checking the configuration of your database instance and looking for the KMS key used for encryption.

2. Next, you need to check if the KMS key is unique. You can do this by querying the Cloud KMS API for a list of all the KMS keys in your project and checking if the key used in the DB tier is unique.

3. If the KMS key is not unique, you need to create a new KMS key and update the configuration of your database instance to use the new key. You can use the Cloud KMS API to create a new key and update the configuration of your database instance using the Cloud SQL Admin API.

Here’s an example Python code that you can use to create a new KMS key and update the configuration of your database instance:

import google.auth
from google.cloud import kms_v1
from google.cloud.sql_v1beta4 import SqlInstancesServiceClient
from google.cloud.sql_v1beta4.types import SqlInstancesSetBackupEncryptionRequest

# Authenticate using the default credentials
credentials, project_id = google.auth.default()

# Create a KMS client
kms_client = kms_v1.KeyManagementServiceClient(credentials=credentials)

# Create a new KMS key
key_name = kms_client.key_ring_path(project_id, 'my-key-ring', 'my-key')
key = kms_client.create_crypto_key(key_name, kms_v1.CryptoKey.CryptoKeyPurpose.ENCRYPT_DECRYPT)

# Update the configuration of your database instance to use the new key
instance_client = SqlInstancesServiceClient(credentials=credentials)
instance_name = 'projects/{}/instances/{}'.format(project_id, 'my-instance')
encryption_config = {
    'kms_key_name': key_name,
}
request = SqlInstancesSetBackupEncryptionRequest(
    instance=instance_name,
    project=project_id,
    body={
        'encryptionConfig': encryption_config,
    }
)
instance_client.set_backup_encryption(request=request)

Note: This is just an example code and you may need to modify it to fit your specific use case. Also, make sure to test the code in a non-production environment before applying it to your production environment.