The CloudWatch agent is running on Linux EC2 and already sends OS metrics. Its operating-system user can read /var/log/app.log, and CloudWatch Logs IAM permissions and connectivity are ready.
Add new log lines to a chosen log group with separate streams per instance, while preserving existing metric collection.
Which configuration and application method is most appropriate?
Configure the agent logs section and apply a configuration that preserves existing metric collection.
Detailed explanation
A destination alone does not add file reading and delivery on EC2.
A destination alone does not add file reading and delivery on EC2.
Metric dimensions identify numeric measurements; they do not collect file contents.
Metric dimensions identify numeric measurements; they do not collect file contents.
Saving the source file alone does not update the running collection settings.
Saving the source file alone does not update the running collection settings.
The agent needs both the file/destination mapping and an applied runtime configuration.
The agent needs both the file/destination mapping and an applied runtime configuration.
Check official documentation
Compare the following points with the official documentation.
Review logs/collect_list, file_path, stream-name variables, and fetch-config/append-config application.
Official references
What to confirm
Map a file to its destination and distinguish saving/applying settings and OS/AWS permissions.
Key points
- CloudWatch agent
- File log
- Log group
Notes
- Environment: AWS SOA-C03 exam guide and the linked AWS documentation
- Reviewed against the linked AWS documentation on 2026-10-04.
Foundation review
Map the source and destination
In collect_list, file_path identifies the OS file; log_group_name and log_stream_name identify CloudWatch destinations. Use {instance_id} in stream names to distinguish instances. The metrics section does not enable file-log collection.
Apply settings and confirm runtime behavior
fetch-config replaces the active configuration set, so include existing metrics in the replacement. append-config can add a configuration; review matching file-name behavior. Apply and start or restart the agent, then check a test record and agent logs. OS read access is separate from IAM permissions and network delivery.