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I don't think I've ever seen an error from the "docker engine" on AWS Fargate. There is a task status field on the task, so if your container completely fails t

I don't think I've ever seen an error from the "docker engine" on AWS Fargate. There is a task status field on the task, so if your container completely fails to start because you have a bad entrypoint command that can't be executed or your process immediately exits with a non zero exit code without outputting anything to stdout/stderr you will see a task status that says that the task stopped unexpectedly because the container exited, and why the container exited. If your containerized process does start and output to stdout/stderr, but then crashes for some reason you can see those stdout/stderr logs in CloudWatch, via the awslogs logging driver. In general I'd say the docker engine logs are the wrong place to try to diagnose an app running AWS Fargate. The point of AWS Fargate is to abstract away the Docker daemon, and just run your containers for you. So if the Docker engine itself was failing for some reason that is an issue for the AWS team on call to fix. Your area of responsibility starts with the application code that is running inside your container. The bits outside the container are the responsibility of an AWS employee.

mosselman 7y ago
In practice there are situations where you do want to see the error logs about your containers. I can't think of an example right now, but sometimes container configurations can be the cause of errors and seeing the logs is essential in not spending hours on investigating.
- NathanKP 7y ago
  With AWS Fargate you can't interact directly with Docker in any way, you just use Fargate via an AWS API, and Fargate handles the rest. So we do validation in the task definition you supply via API to make sure that things check out before AWS Fargate launches the container. So you shouldn't see a "container configuration" based error because our API catches config issues first and won't let you create a task definition that is invalid. If there was such an error that caused Fargate to construct a bad container run command and fail to launch the container that would be a missing validation or bug inside our code and we'd fix that. If you do find something like this please reach out to me or open an AWS support ticket for the oncall team to look at, and we'll fix it!

mosselman 7y ago

In practice there are situations where you do want to see the error logs about your containers. I can't think of an example right now, but sometimes container configurations can be the cause of errors and seeing the logs is essential in not spending hours on investigating.

NathanKP 7y ago
With AWS Fargate you can't interact directly with Docker in any way, you just use Fargate via an AWS API, and Fargate handles the rest. So we do validation in the task definition you supply via API to make sure that things check out before AWS Fargate launches the container. So you shouldn't see a "container configuration" based error because our API catches config issues first and won't let you create a task definition that is invalid. If there was such an error that caused Fargate to construct a bad container run command and fail to launch the container that would be a missing validation or bug inside our code and we'd fix that. If you do find something like this please reach out to me or open an AWS support ticket for the oncall team to look at, and we'll fix it!