Does this SAM deprecation affect both the server APIs and client appliance (the SAM component shipped as docker containers with grafana-prometheus-iris, etc), or can the SAM Serverside APIs with custom metrics still be used?

We also tried this example on a Windows Instances, where the general method still works, but required some Windows Specific Changes for AWS:
- To first assign the secondary IP Address (the VIP) to the Windows Instances, it needs to be done differently, as Windows requires to first set the primary IP as a Fixed (non DHCP address) before adding a secondary address, as documented by AWS here:
https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/config-windows-multiple-ip.html

- the python script for ZMIRROR also needs some tweeking to remove the OS dependant commands, so for testing this, we simply removed the first part of the script that uses the OS to dynamically determine the value of the assigned VIP and replaced it with the pre-determined (fixed) value.

With these small changes, it worked like a charm. Thanks Eduard!

Great Article!
For the EC2 instance to be able to manipulate the route table in the VPC , we created some policy in AWS IAM, assigned it to a Role, and assigned this Role to both EC2 instances.
The Policy was as follow (a better solution would be more restrictive and limit this policy to the VPC where the EC2 instance Run):
 

{
	"Version": "2012-10-17",
	"Statement": [
		{
			"Effect": "Allow",
			"Action": [
				"ec2:DescribeInstances",
				"ec2:CreateRoute",
				"ec2:DeleteRoute",
				"ec2:DescribeRouteTables"
			],
			"Resource": "*"
		}
	]
}