AWS Batch - Cloudwatch Logs operation error

Question

Hello,

Does anyone know why AWS Batch jobs can't start anymore since this morning around 6AM UTC in Frankfurt region?

I get this as the reason in AWS Batch job attempt details:

Reason

```
CannotStartContainerError: Error response from daemon: failed to create task for container: 
failed to initialize logging driver: failed to create Cloudwatch log stream: operation error 
CloudWatch Logs: CreateLogStream, https response error StatusCode: 400
```

```
failed to create Cloudwatch log stream: operation error
```

Any ideas what `operation error` means?

There is no info on what is wrong exactly. I can create Cloudwatch Log stream manually or from ECS so it's not a quota limit issue. It's only AWS Batch jobs that get the above 400 error about cloudwatch logs.

Thank you for any help.

Accepted Answer

The problem was the underlying EC2 instance. It stopped operating normally for some reason. After terminating it and starting a new instance for the batch cluster the jobs started running again and the log stream were being created and populated with events.

Answer

It sounds like the issue is related to throttling errors when creating CloudWatch log streams from AWS Batch jobs. 
Can you check on these ? 
* Verify that the IAM role used by the AWS Batch job has permissions to create log streams in CloudWatch Logs.
* Check if you are hitting the CloudWatch Logs throttling limits. Each AWS account has a limit on the number of log events it can ingest per second across all log groups. Batch jobs creating logs concurrently could exceed this limit.
* Try increasing the logging retries configuration in the AWS Batch job definition. This will make the job retry creating log streams on throttling
errors before failing.

```
 "containerProperties": {
  "logConfiguration": {
    "logDriver": "awslogs",
    "options": {
      "awslogs-group": "/aws/batch/job", 
      "awslogs-region": "us-east-1",
      "awslogs-stream-prefix": "job",
      "awslogs-create-group": "true",
      "awslogs-retries": "5" 
    }
  }
}

```

AWS Batch - Cloudwatch Logs operation error

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