I think we want to have more flexibility that requiring each model to specify all the parameters. For example I expect that the AMI ID is likely to be common across significant chunks of a layout. This pull request implements support for that. It's submitted as a pull request because it is a backward incompatible change and because it breaks existing layouts.
I recommend that we retire the example layout and just use tests/layout.yml after merging this.
I think we want to have more flexibility that requiring each model to specify all the parameters. For example I expect that the AMI ID is likely to be common across significant chunks of a layout. This pull request implements support for that. It's submitted as a pull request because it is a backward incompatible change and because it breaks existing layouts. I recommend that we retire the example layout and just use tests/layout.yml after merging this.
cc: @kdienes