This section discusses how to develop, debug, review, and test modules.
Ansible modules are reusable, standalone scripts that can be used by the Ansible API,
or by the ansible or ansible-playbook programs. They
return information to ansible by printing a JSON string to stdout before
exiting. They take arguments in one of several ways which we’ll go into
as we work through this tutorial.
See All modules for a list of existing modules.
Modules can be written in any language and are found in the path specified
by ANSIBLE_LIBRARY or the --module-path command line option or
in the library section of the Ansible configuration file.
Before diving into the work of creating a new module, you should think about whether you actually should
develop a module. Ask the following questions:
- Does a similar module already exist?
There are a lot of existing modules available, you should check out the list of existing modules at Importing Modules
- Has someone already worked on a similar Pull Request?
It’s possible that someone has already started developing a similar PR. There are a few ways to find open module Pull Requests:
If you find an existing PR that looks like it addresses the issue you are trying to solve, please provide feedback on the PR - this will speed up getting the PR merged.
- Should you use or develop an action plugin instead?
Action plugins get run on the master instead of on the target. For modules like file/copy/template, some of the work needs to be done on the master before the module executes on the target. Action plugins execute first on the master and can then execute the normal module on the target if necessary.
For more information about action plugins, read the action plugins documentation here.
- Should you use a role instead?
Check out the roles documentation available here.
- Should you write multiple modules instead of one module?
The following guidelines will help you determine if your module attempts to do too much, and should likely be broken into several smaller modules.
- Modules should have a concise and well defined functionality. Basically, follow the UNIX philosophy of doing one thing well.
- Modules should not require that a user know all the underlying options of an api/tool to be used. For instance, if the legal values for a required module parameter cannot be documented, that’s a sign that the module would be rejected.
- Modules should typically encompass much of the logic for interacting with a resource. A lightweight wrapper around an API that does not contain much logic would likely cause users to offload too much logic into a playbook, and for this reason the module would be rejected. Instead try creating multiple modules for interacting with smaller individual pieces of the API.
Ansible provides a number of module utilities that provide helper functions that you can use when developing your own modules. The basic.py module utility provides the main entry point for accessing the Ansible library, and all Ansible modules must, at minimum, import from basic.py:
from ansible.module_utils.basic import *
The following is a list of module_utils files and a general description. The module utility source code lives in the ./lib/module_utils directory under your main Ansible path - for more details on any specific module utility, please see the source code.
- api.py - Adds shared support for generic API modules.
- azure_rm_common.py - Definitions and utilities for Microsoft Azure Resource Manager template deployments.
- basic.py - General definitions and helper utilities for Ansible modules.
- cloudstack.py - Utilities for CloudStack modules.
- database.py - Miscellaneous helper functions for PostGRES and MySQL
- docker_common.py - Definitions and helper utilities for modules working with Docker.
- ec2.py - Definitions and utilities for modules working with Amazon EC2
- facts/- Folder containing helper functions for modules that return facts. See https://github.com/ansible/ansible/pull/23012 for more information.
- gce.py - Definitions and helper functions for modules that work with Google Compute Engine resources.
- ismount.py - Contains single helper function that fixes os.path.ismount
- keycloak.py - Definitions and helper functions for modules working with the Keycloak API
- known_hosts.py - utilities for working with known_hosts file
- manageiq.py - Functions and utilities for modules that work with ManageIQ platform and its resources.
- mysql.py - Allows modules to connect to a MySQL instance
- netapp.py - Functions and utilities for modules that work with the NetApp storage platforms.
- network/a10/a10.py - Utilities used by the a10_server module to manage A10 Networks devices.
- network/aci/aci.py - Definitions and helper functions for modules that manage Cisco ACI Fabrics.
- network/aireos/aireos.py - Definitions and helper functions for modules that manage Cisco WLC devices.
- network/aos/aos.py - Module support utilities for managing Apstra AOS Server.
- network/aruba/aruba.py - Helper functions for modules working with Aruba networking devices.
- network/asa/asa.py - Module support utilities for managing Cisco ASA network devices.
- network/avi/avi.py - Helper functions for modules working with AVI networking devices.
- network/bigswitch/bigswitch_utils.py - Utilities used by the bigswitch module to manage Big Switch Networks devices.
- network/cloudengine/ce.py - Module support utilities for managing Huawei Cloudengine switch.
- network/cnos/cnos.py - Helper functions for modules working on devices running Lenovo CNOS.
- network/common/config.py - Configuration utility functions for use by networking modules
- network/common/netconf.py - Definitions and helper functions for modules that use Netconf transport.
- network/common/parsing.py - Definitions and helper functions for Network modules.
- network/common/network.py - Functions for running commands on networking devices
- network/common/utils.py - Defines commands and comparison operators and other utilises for use in networking modules
- network/dellos6/dellos6.py - Module support utilities for managing device running Dell OS6.
- network/dellos9/dellos9.py - Module support utilities for managing device running Dell OS9.
- network/dellos10/dellos10.py - Module support utilities for managing device running Dell OS10.
- network/enos/enos.py - Helper functions for modules working with Lenovo ENOS devices.
- network/eos/eos.py - Helper functions for modules working with EOS networking devices.
- network/fortios/fortios.py - Module support utilities for managing FortiOS devices.
- network/ios/ios.py - Definitions and helper functions for modules that manage Cisco IOS networking devices
- network/iosxr/iosxr.py - Definitions and helper functions for modules that manage Cisco IOS-XR networking devices.
- network/ironware/ironware.py - Module support utilities for managing Brocade IronWare devices.
- network/junos/junos.py - Definitions and helper functions for modules that manage Junos networking devices.
- network/netscaler/netscaler.py - Utilities specifically for the netscaler network modules.
- network/nso/nso.py - Utilities for modules that work with Cisco NSO.
- network/nxos/nxos.py - Contains definitions and helper functions specific to Cisco NXOS networking devices.
- network/onyx/onyx.py - Definitions and helper functions for modules that manage Mellanox ONYX networking devices.
- network/ordance/ordance.py - Module support utilities for managing Ordnance devices.
- network/sros/sros.py - Helper functions for modules working with Open vSwitch bridges.
- network/vyos/vyos.py - Definitions and functions for working with VyOS networking
- openstack.py - Utilities for modules that work with Openstack instances.
- openswitch.py - Definitions and helper functions for modules that manage OpenSwitch devices
- powershell.ps1 - Utilities for working with Microsoft Windows clients
- pure.py - Functions and utilities for modules that work with the Pure Storage storage platforms.
- pycompat24.py - Exception workaround for Python 2.4.
- rax.py - Definitions and helper functions for modules that work with Rackspace resources.
- redhat.py - Functions for modules that manage Red Hat Network registration and subscriptions
- service.py - Contains utilities to enable modules to work with Linux services (placeholder, not in use).
- shell.py - Functions to allow modules to create shells and work with shell commands
- six/__init__.py - Bundled copy of the Six Python library to aid in writing code compatible with both Python 2 and Python 3.
- splitter.py - String splitting and manipulation utilities for working with Jinja2 templates
- urls.py - Utilities for working with http and https requests
- vca.py - Contains utilities for modules that work with VMware vCloud Air
- vmware.py - Contains utilities for modules that work with VMware vSphere VMs
