Chef has long supported Ruby 1.8.7 and REE, even beyond the announced EOL periods from the Ruby maintainers. The continued support for Ruby 1.8 has been a burden for cookbook developers who want to use the "new" Ruby 1.9 features, but must retain support for Ruby 1.8. Chef 12 has officially dropped support for Ruby 1.8!
As of opscode/chef@cf6ac3, Chef no longer supports the Ruby 1.8. This is an exciting advancement in the Chef ecosystem and hopefully increases the level of awesome!
It is worth noting that support for older versions of Ruby 1.9 has also been dropped, including:
Chef now requires Ruby 1.9.3+.
For users running older operating systems which do not ship with a modern Ruby, you can still install Chef using the Omnibus installer. This will include a proper Ruby version and is the recommended way to install Chef on a system.
Seth Vargo is an engineer at Google Cloud. Previously he worked at HashiCorp, Chef Software, CustomInk, and some Pittsburgh-based startups. He is the author of Learning Chef and is passionate about reducing inequality in technology. When he is not writing, working on open source, teaching, or speaking at conferences, Seth advises non-profits.