Cloudwatch: monitor average NetworkIn across EC2s in an auto-scale group

Question

I want to create a cloudwatch metric that monitors the average NetworkIn across all the EC2 machines in an auto-scale group.

Is this possible? It seems that I might be able to monitor the total NetworkIn in various ways, but I want to monitor the average. The reason is that I want to add nodes to the auto-scale group when per-node network traffic is above a threshold, for an application whose bottleneck is networkIn.

Answer 1

Apparently it is possible: You can use the AutoScalingGroupName dimension and Average statistic and it will average across all nodes in the auto scaling group. Here's the command I used:

mon-put-metric-alarm ALARM-NAME --comparison-operator GreaterThanThreshold \
--evaluation-periods 2 --metric-name NetworkIn --namespace "AWS/EC2" \
--dimensions "AutoScalingGroupName=AUTOSCALE-NAME" --period 60 \
--statistic Average --threshold 30000000 \
--alarm-actions arn:aws:autoscaling:etc-etc-etc-scaling-policy