The error 'elasticache failed to retrieve file from s3' indicates that Elasticache was unable to fetch a necessary file from Amazon S3. The cause could be due to incorrect credentials, network interruptions, insufficient permissions, or an improperly configured S3 bucket policy. Additionally, the issue could also arise from an Elasticache node malfunction.
To rectify this error, consider the following solutions:
Verify Credentials: Ensure that AWS access key and secret access key are correct, and that the IAM user has sufficient access permissions to the S3 bucket.
Network Connectivity Check: Use tools like traceroute or ping to validate that there are no networking issues between Elasticache and S3.
Check the S3 Bucket Policy: Add the Elasticache node's IP address or security group in the S3 bucket policy to allow access to the required files.
Restart the Elasticache Node: Rebooting or restarting the Elasticache cluster can sometimes resolve the issue.
Contact AWS Support: If none of the above solutions work, seek assistance from AWS support in resolving the issue.
By following these steps, you should be able to tackle the 'elasticache failed to retrieve file from s3' error and bring your Elasticache cluster back online.