How to solve 'Inaccessible-encryption-credentials' in AWS RDS

Encountering the Inaccessible-encryption-credentials status on an AWS RDS instance can be frustrating, especially when you urgently need to access your database. This issue usually arises when RDS cannot access the encryption key managed by AWS KMS (Key Management Service). Even if the key is active in KMS, several steps might be needed to resolve the issue.

Common Causes

1. Key Access Limitations: The RDS instance may lack the necessary permissions to use the KMS key.
2. KMS Key Unavailability: Temporary issues such as KMS activation delays after re-enabling a suspended account.
3. AWS UI Bugs: Occasionally, the AWS Management Console may fail to reflect the updated status of a key, leaving actions like reboot or restart unavailable.

Step-by-Step Resolution

1. Verify the KMS Key Accessibility

• Go to the AWS Management Console > KMS > Customer Managed Keys.
• Click the key associated with your RDS instance.
• Check if you can edit the key. If you encounter errors such as AccessDeniedException, wait until the key becomes fully accessible.

2. Reboot the RDS Cluster

Once the key is accessible, reboot the RDS cluster. If the AWS Management Console does not allow this action, use the AWS CLI:

aws rds start-db-cluster --db-cluster-identifier <cluster-identifier>

Replace <cluster-identifier> with your RDS cluster's identifier.

3. Restore from a Snapshot if Necessary

If rebooting does not resolve the issue and the status persists, the database might need to be restored. Follow these steps:

• Go to the AWS RDS console.
• Select the problematic database.
• Click Actions > Restore from Snapshot.
• Choose a recent snapshot and configure the new database instance.

This approach creates a new RDS instance based on the selected snapshot, which might resolve the encryption issue.

Notes and Tips

• Ensure your AWS CLI is set up with the required permissions. Use an IAM user with AWSRDSFullAccess and AWSKMSFullAccess policies.
• If the RDS instance still does not start after restoring, double-check the KMS key and permissions.
• Always monitor the Events section of the RDS console for additional insights into the issue.

Preventive Measures

1. Monitor Account Status: Avoid account suspensions by ensuring timely payments.
2. Review Key Permissions: Regularly audit IAM roles and policies to ensure RDS has access to its KMS keys.
3. Use Multi-AZ Deployments: For critical workloads, consider deploying RDS in Multi-AZ mode for added reliability.

Final Thoughts

While resolving the Inaccessible-encryption-credentials status can be complex, a systematic approach helps minimize downtime. Rebooting the cluster often works, but restoring from a snapshot might be the last resort if the issue persists. By taking preventive measures, you can avoid similar issues in the future and maintain a robust RDS environment.