How to monitor all ec2 by CPU usage via CloudWatch

I am trying to set up monitoring of a large number of ec2s and their number is constantly changing. I would like the owner of this instance to receive a notification when the CPU usage is low for a long time.

I can create a function that would get a list of all ec2s, then get their CPU utilization, then send messages to the owners. This option does not suit me, since it takes some time to monitor the state, and not get the CPU utilization values per second of the function launch. And in general, this method looks bad.

I can set up alarm in cloudwatch, but only for one specific instance. This option is not suitable, since there are a lot of ec2 and their number varies.

I can create a dashboard with ec2 names and their CPU utilization. This dashboard will be dynamically replenished. But I haven't figured out how to send notifications from it.

How can I solve my problem without third-party solutions?

Please see this AWS document https://aws.amazon.com/blogs/mt/use-tags-to-create-and-maintain-amazon-cloudwatch-alarms-for-amazon-ec2-instances-part-1/

You will find some existing Lambda functions which will create Cloudwatch alert after creating EC2 instance automatically.

It looks a little bit tricky but worth seeing if you really want to make it automatic. But yes single cloud watch alert can't monitor multiple EC2 instances.

Another thing, same sample lambda function you will find from the existing template and it will directly create that lambda function and you can test it.

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