Mitogen is a Python library for writing distributed self-replicating programs.

There is no requirement for installing packages, copying files around, writing shell snippets, upfront configuration, or providing any secondary link to a remote machine aside from an SSH connection. Due to its origins for use in managing potentially damaged infrastructure, the remote machine need not even have free disk space or a writeable filesystem.

It is not intended as a generic RPC framework; the goal is to provide a robust and efficient low-level API on which tools like Salt, Ansible, or Fabric can be built, and while the API is quite friendly and comparable to Fabric, ultimately it is not intended for direct use by consumer software.

The focus is to centralize and perfect the intricate dance required to run Python code safely and efficiently on a remote machine, while avoiding temporary files or large chunks of error-prone shell scripts, and supporting common privilege escalation techniques like sudo, potentially in combination with exotic connection methods such as WMI, telnet, or console-over-IPMI.

An experimental extension to Ansible is included that implements host connections over Mitogen, replacing embedded shell invocations with pure-Python equivalents invoked via highly efficient remote procedure calls tunnelled over SSH. No changes are required to the target hosts.

The extension isn’t nearly in a generally dependable state yet, however it already works well enough for testing against real-world playbooks. Bug reports in this area are very welcome – Ansible is a huge beast, and only significant testing will prove the extension’s soundness.