Clarification on AWS ECS Logging Configuration

When configuring logging for AWS ECS (Elastic Container Service), there are a few important points to consider:

1. Using the awslogs driver with CloudWatch: The awslogs driver is built into ECS and doesn't require the installation of a separate CloudWatch agent. It doesn't consume significant additional resources beyond what your application is already using. When you configure the awslogs driver in your task definition, ECS handles the log streaming to CloudWatch Logs without needing extra CPU or memory allocation. So, if you've set a limit of 800 MB for your container, you typically don't need to increase this limit just to use the awslogs driver.

2. "Export logs to journald" option: The "Export logs to journald" option is not a standard feature in ECS. ECS primarily uses the awslogs driver to send logs directly to CloudWatch Logs. The journald system is more commonly associated with systemd on Linux systems. It's possible you're referring to a custom configuration or a different service.

3. Logging agents and resource requirements: The built-in awslogs driver in ECS doesn't require significant additional resources. However, if you choose to use more advanced logging solutions like AWS FireLens or third-party logging agents (e.g., Fluentd), these may require additional CPU and memory resources. The exact requirements would depend on the specific agent and your logging volume.

When configuring logging for ECS, the recommended and most straightforward approach is to use the awslogs driver. This method is efficient, doesn't require additional resource allocation, and integrates seamlessly with CloudWatch Logs. If you need more advanced log routing or processing capabilities, you might consider AWS FireLens, but be aware that this could require additional resources.

Remember to configure your task definition's log configuration section properly, specifying the log driver as "awslogs" and setting appropriate options like awslogs-group, awslogs-region, and awslogs-stream-prefix. This ensures your container logs are correctly sent to CloudWatch Logs without the need for a separate agent or significant additional resources.

Sources
How to push custom application logs to cloudwatch | AWS re:Post
Amazon ECS container logs for EC2 and Fargate launch types - AWS Prescriptive Guidance
LogConfiguration - Amazon Elastic Container Service