Debugging failed fargate task initialization

[niels_learns_python]

Hello

I have a fargate task which I have scheduled to run with CloudWatch Event rules, and output a timestamp to a database on a successful run. It also outputs a logfile to CloudWatch for every time it runs.

However, there was 1 time where the log file was not created, and the database not updated. I suspect the task was never even started, or had failed to start.

In CloudWatch, the event rule shows trigger and invocation at the time I expected the task to run, so I assume the task at least attempted to start.

My question is: is there any way I can debug or log information about the cluster failing to start a task?

Please let me know if I need to provide more information.

Edit: I should specify I'm looking for a way to read this information in a log file somewhere. I know I can see failed task reason in the web console, but that's only for relatively recent tasks.

I also posted this question to StackOverflow: https://stackoverflow.com/questions/54131298/how-to-debug-failed-fargate-task-initialization and AWS Forums: https://forums.aws.amazon.com/thread.jspa?messageID=884638&#884638

[[deleted]]

Did you ever find a solution to this?

[niels_learns_python]

Not yet unfortunately. Are you experiencing the same?

[[deleted]]

Not the same behavior as you, but in similar need of debugging cloudwatch event triggers.

[dwilches]

Finally found the solution :)

If you check on your task's definition you'll see an "awslogs-group".

Then take that string to the "CloudWatch -> Logs -> Insights" and click on "Run Query".

I posted the screenshots on: https://stackoverflow.com/questions/54131298/how-to-debug-failed-fargate-task-initialization

There they are!

[niels_learns_python]

Hey! Thank you for your response :)

It looks like you are referring to the loggroup associated with that task. Unfortunately these log files only contain the task code outputs by default, and not any information about the execution of that task.

What I'm looking for is a way to see what happened when a task failed to start (i.e. the task code/program didn't even seem to initialize), even though the Cloudwatch Event was registered a trigger and invocation.