In this chapter, we've gained an understanding of how Puppet's variable and data type system works, including the basic data types: Strings, Numbers, Booleans, Arrays, and Hashes. We've seen how to interpolate variables in strings and how to quickly create sets of similar resources using an array of resource names. We've learned how to set common attributes for resources using a hash of attribute-value pairs and the attribute splat operator.
We've seen how to use variables and values in expressions, including arithmetic expressions, and explored the range of Puppet's comparison operators to generate Boolean expressions. We've used conditional expressions to build if…else and case statements and had a brief introduction to regular expressions.
We've learned how Puppet's Facter subsystem supplies information about the node via the facts hash and how to use facts in our own manifests and in expressions. We've pointed out some key facts, including the operating system release, the system...