Configsets can be written with ERB and YAML also. Writing configsets with YAML can be useful for very simple configsets.
AWS::CloudFormation::Init: config: packages: yum: httpd:  files: "/var/www/html/index.html": content: | <%= indent(@html, 10) %> services: sysvinit: httpd: enabled: true ensureRunning: true
indent method is a built-in helper for ERB. It aligns the text and is useful for YAML-based configsets. The
@html variable can be set by the author of the configset or overridden by you with variables.
Pro tip: Use the <- and -> arrow keys to move back and forward.