We often need Puppet to have access to secret information, such as passwords or crypto keys, for it to configure systems properly. But how do you avoid putting such secrets directly into your Puppet code, where they're visible to anyone who has read access to your repository?

It's a common requirement for third-party developers and contractors to be able to make changes via Puppet, but they definitely shouldn't see any confidential information. Similarly, if you're using a distributed Puppet setup like that described in Chapter 2, Puppet Infrastructure, every machine has a copy of the whole repo, including secrets for other machines that it doesn't need and shouldn't have. How can we prevent this?

One answer is to encrypt the secrets using the GnuPG tool, so that any secret information in the Puppet repo is undecipherable (for all practical purposes) without the appropriate key. Then we distribute the key securely to the people or machines that need it.