AWS Certified Developer – Associate — Question 292

A developer wants to debug an application by searching and filtering log data. The application logs are stored in Amazon CloudWatch Logs. The developer creates a new metric filter to count exceptions in the application logs. However, no results are returned from the logs.

What is the reason that no filtered results are being returned?

Answer options

• A. A setup of the Amazon CloudWatch interface VPC endpoint is required for filtering the CloudWatch Logs in the VPC.
• B. CloudWatch Logs only publishes metric data for events that happen after the filter is created.
• C. The log group for CloudWatch Logs should be first streamed to Amazon OpenSearch Service before metric filtering returns the results.
• D. Metric data points for logs groups can be filtered only after they are exported to an Amazon S3 bucket.

Correct answer: B

Explanation

Amazon CloudWatch Logs metric filters are not retroactive and only extract metric data from log events ingested after the filter is created. Historical log data is not evaluated by newly created filters, which explains why no results are immediately returned. Streaming to Amazon OpenSearch Service, exporting to Amazon S3, or setting up interface VPC endpoints are not prerequisites for basic metric filtering.