if i understand, the new server of your client is runing with W2K12 and it's it that needs ssh ?
No its the Amazon Linux Mysql host that requires it
Howwver I need to create ODBC Data source on Windows that FMS can use to support an ESS connection where the MySql db is hosted on Amazon
You'll need to create an SSH tunnel on the FileMaker Server.
You can use a tool like Plink (command line interface for Putty) to do this.
If you Google "Putty" you should be able to download Putty and Plink.
From the command line you can create an SSH tunnel like so:
plink <Amazon MySQL server fqdn or IP> -P <ssh port, usually 22> -l <username> -pw <password> -L 3306:127.0.0.1:3306 -N
This will map port 3306 on the Windows Server to port 3306 on the Amazon server over SSH.
If you want to change the port Windows Server uses, change the first instance of 3306.
When setting up the ODBC connection on Windows Server, connect using 127.0.0.1 port 3306 (or whatever local port you specified above).
You'll probably want to make this some sort of start-up script on the Windows server so it will re-connect after reboots.