ansible/README.md

Ansible

Ansible is a extra-simple Python API for doing 'remote things' over SSH.

As Func, which I co-wrote, aspired to avoid using SSH and have it's own daemon infrastructure, Ansible aspires to be quite different and more minimal, but still able to grow more modularly over time.

Principles

• Dead simple setup
• No server or client daemons, uses existing SSHd
• Only SSH keys are allowed for authentication
• usage of ssh-agent is more or less required
• plugins can be written in ANY language
• as with Func, API usage is an equal citizen to CLI usage

Requirements

• python 2.6 -- or a backport of the multiprocessing module
• paramiko

Inventory file

The default inventory file (-H) is ~/.ansible_hosts and is a list of all hostnames to target with ansible, one per line.

This list is further filtered by the pattern wildcard (-P) to target specific hosts.

Comamnd line usage example

Run a module by name with arguments

ssh-agent bash ssh-add ~/.ssh/id_rsa.pub ansible -p "*.example.com" -m modName -a "arg1 arg2"

API Example

The API is simple and returns basic datastructures.

import ansible runner = ansible.Runner(command='inventory', host_list=['xyz.example.com', '...']) data = runner.run()

{ 'xyz.example.com' : [ 'any kind of datastructure is returnable' ], 'foo.example.com' : None, # failed to connect, ... }

Additional options to runner include the number of forks, hostname exclusion pattern, library path, and so on.

Parallelism

Specify the number of forks to use, to run things in greater parallelism.

ansible -f 10 "*.example.com" -m modName -a "arg1 arg2"

Bundled Modules

See the example library for modules, they can be written in any language and simply return JSON to stdout. The path to your ansible library is specified with the "-L" flag should you wish to use a different location than "~/ansible".

Features not supported from Func (by design)

• Delegation for treeish topologies
• Asynchronous modes for long running tasks -- background tasks on your own

Future plans

• Dead-simple declarative configuration management & facts engine, with probes implementable in any language.

Author

• Michael DeHaan michael.dehaan@gmail.com | http://michaeldehaan.net/