SaltStack (http://saltstack.com/community.html) and Ansible (http://ansible.cc) would be your two closest options. Of the two, I prefer Ansible for its simplicity and the fact that it can be extended in any language, but it's worth noting that that simplicity currently comes at a cost of power compared to Chef. (E.g., Chef has a concept of "ensure this service is present," and that works on all supported operating systems, whereas Ansible has different modules for different supervisors.)