How to monitor EC2 instances by memory?

Question

Using Cloudwatch you can monitor your EC2 instances by several criteria, such as network usage, CPU usage, and so on…

Unfortunately, there is no metric for memory consum

Answer 1

Well, now the new CloudWatch agent can collect metrics like memory and disk usage, see the docs.

With this you can monitor this kind of metrics, but you will need to install and configure the agent in the instances.