Missing log lines when writing to cloudwatch from ECS Docker containers

Question

(Docker container on AWS-ECS exits before all the logs are printed to CloudWatch Logs) Why are some streams of a CloudWatch Logs Group incomplete (i.e., the Fargate Docker Conta

Answer 1

Just contacted AWS support about this issue and here is their response:

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Based on that case, I can see that this occurs for containers in a Fargate Task that exit quickly after outputting to stdout/stderr. It seems to be related to how the awslogs driver works, and how Docker in Fargate communicates to the CW endpoint.

Looking at our internal tickets for the same, I can see that our service team are still working to get a permanent resolution for this reported bug. Unfortunately, there is no ETA shared for when the fix will be deployed. However, I've taken this opportunity to add this case to the internal ticket to inform the team of the similar and try to expedite the process

In the meantime, this can be avoided by extending the lifetime of the exiting container by adding a delay (~>10 seconds) between the logging output of the application and the exit of the process (exit of the container).

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Update: Contacted AWS around August 1st, 2019, they say this issue has been fixed.