Cumin is a Python API and CLI that provides a flexible and scalable way to execute multiple commands on cluster of hosts in parallel. It has a fine-grained hosts selection mechanism that allows to dynamically query multiple backends and combine their results. In addition to some built-in backends such as PuppetDB, SSH known hosts files, OpenStack API, it's possible to plug-in external backends. The current transport layer is SSH, although additional transport layers could be easily added. There are multiple execution strategies available and fine-tunable to suit different orchestration requirements. The executed commands outputs are automatically grouped for readability. The talk will describe the reasons that led us to the development of Cumin and its features and show its current usage at the Wikimedia Foundation for automation and orchestration.