[AWS] Logs

AWS Services provides the various types of logs. In general, you can use CloudWatch Logs & CloudWatch Logs Insights to gather and analyze logs.

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Application Logs

• Application logs are created by applications running in AWS environment or on-premise infrastructures.
• In general, application logs are written in the files in EC2 or on-premise instances.

Applications	Agents	Destination
Custom applications on EC2 or on-premise instances	CloudWatch unified agent	CloudWatch Logs
Lambda	No	Direct integration with CloudWatch Logs
ECS or Fargate	No	Direct integration with CloudWatch Logs
Elastic Beanstalk	No	Direct integration with CloudWatch Logs

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Operating System (OS) Logs

• Event logs or System logs generated by OS in your EC2 or on-premise instances
  • ex) /var/log/messages or /var/log/auth.log
• Usually, you can stream logs to CloudWatch Logs using the CloudWatch unified agent.

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AWS-Managed Logs

Services	Destination
Load Balancer (ALB, NLB) Access Logs	S3
CloudTrail Logs	S3, CloudWatch Logs
VPC Flow Logs	S3, CloudWatch Logs
Route 53 Logs	CloudWatch Logs
S3 Access Logs	S3
CloudFront Access Logs	S3