How do you declare and use variables inside elasticsearch.yml?? I'm running on Windows Server.
I've read this article about Environment variables, but find it to be a bit lacking.
Do they get passed in via the command line?
Can they be declared and initialized at the top of the file?
Are they the Environment Variables set under System Properties > Advanced > Environment Variables?
This is probably a very basic question, but I'm not familiar with .yml files and how they work.