How to Use the Command 'ansible-doc' (with examples)

ansible-doc is a powerful command-line utility in Ansible that provides detailed information about the modules and plugins available within the Ansible library. This tool is particularly useful for users who need quick access to concise and comprehensive data about various Ansible modules and plugins. It aids in understanding the available actions, options, and snippets for integrating these modules into playbooks, thus enhancing the user’s ability to manage and automate configuration processes efficiently.

Use case 1: List Available Action Plugins (Modules)

Code:

ansible-doc --list

Motivation: The ability to list all available action plugins (modules) is immensely beneficial for users who are exploring or are unfamiliar with the modules provided in their Ansible installation. By generating a quick overview, users can easily identify what tools and functionalities they have at their disposal, which can lead to more efficient playbook creation and environment management.

Explanation:

• --list: This flag instructs ansible-doc to provide a comprehensive list of all action plugins (modules) installed in the Ansible library. This straightforward approach saves time for the user by presenting a consolidated view without needing to navigate external documentation.

Example output:

a10_server                     Manage A10 Networks AX/SoftAX/Thunder/vThunder devices' server objects
a10_service_group              Manage A10 Networks AX/SoftAX/Thunder/vThunder devices' service groups
a10_virtual_server             Manage A10 Networks AX/SoftAX/Thunder/vThunder devices' virtual servers
...

Use case 2: List Available Plugins of a Specific Type

Code:

ansible-doc --type connection --list

Motivation: Sometimes users need to delve deeper into specific types of plugins like connection, become, or cache. This ability is crucial for customizing and tailoring their Ansible setup to suit specialized environments or tasks. By focusing on a specific type, users can hone in on the necessary tools without the distraction of irrelevant options, enhancing productivity and precision.

Explanation:

• --type connection: The --type option allows the user to specify a particular category of plugins they are interested in. In this example, ‘connection’ signifies the examination of plugins responsible for managing how Ansible connects to managed hosts.
• --list: Lists all plugins within the specified type, which makes it easier to select the desired plugin for further investigation or use.

Example output:

chroot      Interact with local chroot
docker      Run tasks in docker containers
local       execute on controller
...

Use case 3: Show Information About a Specific Action Plugin (Module)

Code:

ansible-doc apt

Motivation: Accessing detailed information about a specific module, such as its purpose, options, and examples, enables users to effectively implement and leverage it within their playbooks. This feature is particularly valuable when integrating new or seldom-used modules that require a deeper understanding for successful deployment.

Explanation:

• apt: Here, ‘apt’ refers to the specific module the user wants more detailed information on. The command looks up and provides comprehensive details on its functionality, usage, and configurable parameters.

Example output:

> APT    (/usr/share/ansible/plugins/modules/apt.py)

    Manage apt packages.

    OPTIONS (= is mandatory):

    - allow_change
          Default: no
...

Use case 4: Show Information About a Plugin with a Specific Type

Code:

ansible-doc --type connection ssh

Motivation: This specific use case is instrumental when a user needs detailed insights into how a certain type of plugin functions within the Ansible ecosystem. Understanding types like ‘connection’, helps users optimize how Ansible engages with remote systems, which is foundational for executing tasks over different environments.

Explanation:

• --type connection: As in previous examples, this stipulates the desire to focus on plugins categorized as ‘connection’ plugins.
• ssh: This specifies the plugin name within the connection type the user wants to explore, delivering detailed documentation for the SSH connection plugin.

Example output:

> SSH

    This connection plugin allows ansible to communicate with target machines via normal SSH command line.

    OPTIONS:

    - pty
          Default: yes
...

Use case 5: Show the Playbook Snippet for Action Plugins (Modules)

Code:

ansible-doc --snippet apt

Motivation: Generating a playbook snippet is incredibly helpful when users want to quickly embed a fully compliant and functional piece of YAML configuration into their playbooks. This saves time and reduces errors, especially for users who may not be as experienced with writing YAML syntax from scratch.

Explanation:

• --snippet: This parameter tells ansible-doc to generate and display a basic snippet, which demonstrates how to utilize the specified module in an Ansible playbook.
• apt: Specifies the particular module for which the snippet will be generated.

Example output:

- name: Ensure APT package is present
  apt:
    name: pkg
    state: present

Use case 6: Show Information About an Action Plugin (Module) as JSON

Code:

ansible-doc --json apt

Motivation: Outputting module information in JSON format can be critically important for developers or users automating documentation or parsing module data programmatically as part of a CI/CD pipeline or other automated systems. The structured data format facilitates seamless integration into other tools and systems.

Explanation:

• --json: This flag instructs ansible-doc to output the module’s information in a JSON format, which is preferred for machine-readable data.
• apt: Specifies the module for which the JSON formatted data will be extracted.

Example output:

{
    "module": {
        "short_description": "Manage apt packages",
        "version_added": "2.0",
        ...
    }
}

Conclusion:

The ansible-doc command is a versatile tool that provides essential insights and quick references for anyone utilizing the Ansible automation platform. Whether you are listing all available modules, understanding the details of a specific plugin, or needing a playbook snippet, ansible-doc offers streamlined access to the crucial information necessary to perform effective automation and configuration management tasks.