What is the MOST efficient way to meet these requirements?
Write an AWS Lambda function that logs into the EC2 instance to pull the application logs from the EC2 instance and persists them into an Amazon S3 bucket.
Enable AWS CloudTrail logging for the AWS account, create a new Amazon S3 bucket, and then configure Amazon CloudWatch Logs to receive the application logs from CloudTrail.
Create a simple cron job on the EC2 instances that synchronizes the application logs to an Amazon S3 bucket by using rsync.
Install the Amazon CloudWatch Logs Agent on the EC2 instances, and configure it to send the application logs to CloudWatch Logs.
Explanations:
Using AWS Lambda to log into EC2 instances is inefficient and complex. Lambda functions are not ideal for pulling logs from EC2 instances. There are more direct methods.
AWS CloudTrail tracks API calls, not application logs. It cannot collect logs from EC2 instances directly. CloudWatch Logs is more appropriate for this purpose.
Using a cron job with rsync is not optimal for centralized logging, as it requires manual management and introduces potential reliability issues.
Installing the Amazon CloudWatch Logs Agent is the most efficient and scalable solution for collecting application logs from EC2 instances and sending them to CloudWatch.
It appears that the answer is:
Install the Amazon CloudWatch Logs Agent on the EC2 instances, and configure it to send the application logs to CloudWatch Logs.