AWS EC2 Auto-Scaling and CloudWatch Alarm Trigger

Question

I have a double.

You need to have CloudWatch with an alarm to trigger un action to Auto-Scaling works?

Problem.

I have EC2 instances that I would like to do Auto Scaling with a monitor CPU above a certain value add new instance ou below the CPU utilization for values remove a instance.

Auto Scale policies is not sufficient to do this monitoring? I need Cloud watch to trigger an action and call auto scaling to add a new instance?

Accepted Answer

Hello.

If you want to scale EC2 based on CPU usage, I think you can do it by creating a "target tracking scaling policy" by following the steps in the document below.  
When you configure this setting, a CloudWatch Alarm will be created and used for scaling.  
https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-scaling-target-tracking.html#policy_creating

AWS EC2 Auto-Scaling and CloudWatch Alarm Trigger

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