being managed.
Chef is open source. However, to really use it, you must pay for a hosted
version (called Hosted) or a standalone version (called Private) that you can
install inside your corporate firewall with a service contract. Downloading the
source code and getting it up and running is not a trivial task, and support for
the open source version (called Open Source) without a service contract is
limited. That said, like Puppet, Chef is mature and well respected and worth
your time if you need what it offers.
CFEngine
CFEngine is probably the oldest option for automating infrastructure. It is
written in C, so it might be a little faster than the other options. It manages
server builds, deployment, and management, and it performs some very useful
audits and reports. Some really big names are known to use CFEngine, such
as AT&T, IBM, Pixar, and Qualcomm.
CFEngine has open source and enterprise versions. The differences are a little
less extreme than with some of the other options, but again, the enterprise
version has all the flashy chrome and a few really useful features that make it
worth the expenditure for most users who need or want the added benefits
they offer.
Ansible
Ansible is an orchestration engine. It does configuration management,
application deployment, and more. It was a proprietary product, but Red Hat
bought the company that created it and promptly worked its magic to release
the code with an open source license. Much the way Red Hat handles its
enterprise Linux and middleware products, it provides free and open source
Ansible code—but only in source form. You can license binaries from Red
Hat, which the company will then support. Ansible is well respected and
worth looking into.
NOTE
A quick disclosure: Matthew once worked for Canonical and now works for
Red Hat. While we believe we are writing about software without any
special bias, we also think it is only and properly in the spirit of openness to
disclose this fact.