You have an asynchronous processing application using an Auto Scaling Group and an SQS Queue.
The Auto Scaling Group scales according to the depth of the job queue.
The completion velocity of the jobs has gone down, the Auto Scaling Group size has maxed out, but the inbound job velocity did not increase.
What is a possible issue?
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A. B. C. D.Answer - A.
This question is more on the grounds of validating each option.
Option B is invalid because the Route table would have an effect on all worker processes, and no jobs would have been completed.
Option C is invalid because if the IAM Role were invalid, then no jobs would be completed.
Option D is invalid because the scaling is happening.
It's just that the jobs are not getting completed.
For more information on Scaling on Demand, please visit the below URL:
http://docs.aws.amazon.com/autoscaling/latest/userguide/as-scale-based-on-demand.htmlThe issue described suggests that the Auto Scaling Group has reached its maximum capacity and is not scaling up to handle the increased workload. This can happen due to a variety of reasons, and we need to evaluate the possible causes to identify the root cause of the issue.
Answer A: "Some of the new jobs coming in are malformed and unprocessable" - This is a possible reason for decreased completion velocity of jobs. However, this would not cause the Auto Scaling Group to max out and stop scaling up.
Answer B: "The routing tables changed and none of the workers can process events anymore" - This could be a possible reason for the decreased completion velocity of jobs, but again, this would not cause the Auto Scaling Group to max out and stop scaling up.
Answer C: "Someone changed the IAM Role Policy on the instances in the worker group and broke permissions to access the queue" - This could also be a possible reason for decreased completion velocity of jobs. If the instances in the worker group don't have the required permissions to access the queue, they won't be able to process the jobs. However, this would not cause the Auto Scaling Group to max out and stop scaling up.
Answer D: "The scaling metric is not functioning correctly" - This is the most likely reason for the issue. If the scaling metric is not functioning correctly, the Auto Scaling Group won't be able to scale up to handle the increased workload, even though there are enough jobs in the queue. This could happen if the metric is misconfigured, or if there are issues with the monitoring system that provides the metric data.
To diagnose the issue, we should start by reviewing the scaling metric configuration and monitoring system logs to identify any issues. We should also check if there are any changes made to the system recently that could have caused the issue. Once we identify the root cause, we can take appropriate actions to resolve the issue and restore the system to normal functioning.