I am working on a client with a managed environment and we will monitor AWS.
I have seen that I have to install an AG in the AWS environment.
What ports or communications you must have from this host with the other components of the environment: managed server, cluster active gate....
Should I have something else ne account?
The documentation that you are referring to is for the plugin that gets metrics directly from AWS (highly recommended).
If you what to instruments your EC2 instances you need to do a normal One Agent installation and is A best practice to have an ActiveGate in your VPC, so the communication is going to be:
9999 from agent to ActiveGate
443 from ActiveGate to Managed Node