Comtrya is a tool that allows you to configure and provision an operating system through YAML based manifests. Comtrya's goals are:
Run on any operating system
Provide a simple YAML interface to, potentially, complex tasks
This is better, yes?
Comparison to Alternatives
Ansible is a great tool task runner, but comes with a lot of modules that aren't really necessary for localhost provisioning and can be cumbersome to run individual tasks within a playbook.
SaltStack has been a favourite of mine (@rawkode) for many years, and while it's event system is a game changer for working with many devices - it's inability to display progress of large state runs makes it cumbersome to use for localhost provisioning.