Question:
I have put together these commands to autoscale EC2 instances based on SQS queue size. I have run all commands and my queue is at 10 messages and a single instance hasn’t been launched.
I am trying to figure out, what SQS queue my cloudwatch alarms are listening to? Also any help to indentify the issus is appreciated!
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### Create Autoscaling Policy ### aws autoscaling create-launch-configuration --launch-configuration-name my-lc --image-id ami-551c6d30 --instance-type m1.small aws autoscaling create-auto-scaling-group --auto-scaling-group-name my-asg --launch-configuration-name my-lc --availability-zones "us-east-1a" "us-east-1c" --max-size 10 --min-size 0 --desired-capacity 0 # Scale up policy aws autoscaling put-scaling-policy --policy-name my-sqs-scaleout-policy --auto-scaling-group-name my-asg --scaling-adjustment 1 --adjustment-type ChangeInCapacity # Scale down policy aws autoscaling put-scaling-policy --policy-name my-sqs-scalein-policy --auto-scaling-group-name my-asg --scaling-adjustment -1 --adjustment-type ChangeInCapacity # Alarm to scale up aws cloudwatch put-metric-alarm --alarm-name AddCapacityToProcessQueue --metric-name ApproximateNumberOfMessagesVisible --namespace "AWS/SQS" --statistic Average --period 120 --threshold 3 --comparison-operator GreaterThanOrEqualToThreshold --dimensions Name=QueueName,Value=my-queue --evaluation-periods 2 --alarm-actions arn:aws:autoscaling:us-east-1:850082592395:scalingPolicy:6408b62d-9363-4252-a88c-5ffab08a8cb5:autoScalingGroupName/my-asg:policyName/my-sqs-scaleout-policy # Alarm to scale down aws cloudwatch put-metric-alarm --alarm-name RemoveCapacityFromProcessQueue --metric-name ApproximateNumberOfMessagesVisible --namespace "AWS/SQS" --statistic Average --period 300 --threshold 1 --comparison-operator LessThanOrEqualToThreshold --dimensions Name=QueueName,Value=my-queue --evaluation-periods 2 --alarm-actions arn:aws:autoscaling:us-east-1:850082592395:scalingPolicy:4771ea64-2ebf-45ef-9328-50e058dc68b7:autoScalingGroupName/my-asg:policyName/my-sqs-scalein-policy # Verify cloudwatch alarms aws cloudwatch describe-alarms --alarm-names AddCapacityToProcessQueue RemoveCapacityFromProcessQueue # Verify scaling policy aws autoscaling describe-policies --auto-scaling-group-name my-asg # Verify instances autoscaled aws autoscaling describe-auto-scaling-groups --auto-scaling-group-name my-asg |
Answer:
The AWS Documentation states that:
Amazon Simple Queue Service sends data to CloudWatch every 5 minutes.
Additionally, you have specified an Average metric over several periods of time. Therefore, it will require several 5-minute periods to send Amazon SQS metrics to Amazon CloudWatch.
It’s possible that the metric period (120 seconds) is too short to receive multiple updates from SQS, therefore causing INSUFFICIENT_DATA errors.
Start by trying to get the Alarm to trigger with a Maximum setting and play with the time periods. Once the Alarm is successfully triggering, play with the thresholds to get the desired behaviour.