103 lines
2.7 KiB
Markdown
103 lines
2.7 KiB
Markdown
Ansible
|
|
=======
|
|
|
|
Ansible is a extra-simple Python API for doing 'remote things' over SSH.
|
|
|
|
While 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
|
|
* use Python's multiprocessing capabilities to emulate Func's forkbomb logic
|
|
|
|
Requirements
|
|
============
|
|
|
|
For the server the tool is running from, *only*:
|
|
|
|
* 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. These
|
|
can be hostnames or IPs
|
|
|
|
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. Read the source, it's not
|
|
complicated.
|
|
|
|
Parallelism
|
|
===========
|
|
|
|
Specify the number of forks to use, to run things in greater parallelism.
|
|
|
|
ansible -f 10 "*.example.com" -m modName -a "arg1 arg2"
|
|
|
|
10 forks. The default is 3. 5 is right out.
|
|
|
|
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". There is potential for a sizeable community to build
|
|
up around the library scripts.
|
|
|
|
Features not supported from Func (yet?)
|
|
============================================
|
|
|
|
* Delegation for treeish topologies
|
|
* Asynchronous modes for polling long running operations
|
|
|
|
Future plans
|
|
============
|
|
|
|
* Dead-simple declarative configuration management using
|
|
a runbook style recipe file
|
|
* facts engine, including exec'ing facter if present
|
|
|
|
Author
|
|
======
|
|
|
|
Michael DeHaan <michael.dehaan@gmail.com>
|
|
|
|
http://michaeldehaan.net/
|
|
|
|
|