.. _resource_modules:

************************
Network Resource Modules
************************

Ansible network resource modules simplify and standardize how you manage different network devices. Network devices separate configuration into sections (such as interfaces and VLANs) that apply to a network service. Ansible network resource modules take advantage of this to allow you to configure subsections or *resources* within the network device configuration. Network resource modules provide a consistent experience across different network devices.


.. contents::
   :local:

Network resource module states
===============================

You use the network resource modules by assigning a state to what you want the module to do. The resource modules support the following states:

merged
  Ansible merges the on-device configuration with the provided configuration in the task.

replaced
  Ansible replaces the on-device configuration subsection with the provided configuration subsection in the task.

overridden
  Ansible overrides the on-device configuration for the resource with the provided configuration in the task. Use caution with this state as you could remove your access to the device (for example, by overriding the management interface configuration).

deleted
  Ansible deletes the on-device configuration subsection and restores any default settings.

gathered
  Ansible displays the resource details gathered from the network device and accessed with the ``gathered`` key in the result.

rendered
  Ansible renders the provided configuration in the task in the device-native format (for example, Cisco IOS CLI). Ansible returns this rendered configuration in the ``rendered`` key in the result. Note this state does not communicate with the network device and can be used offline.

parsed
  Ansible parses the configuration from the ``running_config`` option into Ansible structured data in the ``parsed`` key in the result. Note this does not gather the configuration from the network device so this state can be used offline.

Using network resource modules
==============================

This example configures the L3 interface resource on a Cisco IOS device, based on different state settings.

 .. code-block:: yaml

   - name: configure l3 interface
     cisco.ios.ios_l3_interfaces:
       config: "{{ config }}"
       state: <state>

The following table shows an example of how an initial resource configuration changes with this task for different states.

+-----------------------------------------+------------------------------------+-----------------------------------------+
| Resource starting configuration         | task-provided configuration (YAML) | Final resource configuration on device  |
+=========================================+====================================+=========================================+
| .. code-block:: text                    |  .. code-block:: yaml              | *merged*                                |
|                                         |                                    |  .. code-block:: text                   |
|   interface loopback100                 |   config:                          |                                         |
|    ip address 10.10.1.100 255.255.255.0 |   - ipv6:                          |    interface loopback100                |
|    ipv6 address FC00:100/64             |    - address: fc00::100/64         |     ip address 10.10.1.100 255.255.255.0|
|                                         |    - address: fc00::101/64         |     ipv6 address FC00:100/64            |
|                                         |    name: loopback100               |     ipv6 address FC00:101/64            |
|                                         |                                    +-----------------------------------------+
|                                         |                                    | *replaced*                              |
|                                         |                                    |  .. code-block:: text                   |
|                                         |                                    |                                         |
|                                         |                                    |   interface loopback100                 |
|                                         |                                    |    no ip address                        |
|                                         |                                    |    ipv6 address FC00:100/64             |
|                                         |                                    |    ipv6 address FC00:101/64             |
|                                         |                                    +-----------------------------------------+
|                                         |                                    | *overridden*                            |
|                                         |                                    |  Incorrect use case. This would remove  |
|                                         |                                    |  all interfaces from the device         |
|                                         |                                    | (including the mgmt interface) except   |
|                                         |                                    |  the configured loopback100             |
|                                         |                                    +-----------------------------------------+
|                                         |                                    | *deleted*                               |
|                                         |                                    |  .. code-block:: text                   |
|                                         |                                    |                                         |
|                                         |                                    |   interface loopback100                 |
|                                         |                                    |    no ip address                        |
+-----------------------------------------+------------------------------------+-----------------------------------------+

Network resource modules return the following details:

* The *before* state -  the existing resource configuration before the task was executed.
* The *after* state - the new resource configuration that exists on the network device after the task was executed.
* Commands - any commands configured on the device.

.. code-block:: yaml

   ok: [nxos101] =>
     result:
       after:
         contact: IT Support
         location: Room E, Building 6, Seattle, WA 98134
         users:
         - algorithm: md5
           group: network-admin
           localized_key: true
           password: '0x73fd9a2cc8c53ed3dd4ed8f4ff157e69'
           privacy_password: '0x73fd9a2cc8c53ed3dd4ed8f4ff157e69'
           username: admin
       before:
         contact: IT Support
         location: Room E, Building 5, Seattle HQ
         users:
         - algorithm: md5
           group: network-admin
           localized_key: true
           password: '0x73fd9a2cc8c53ed3dd4ed8f4ff157e69'
           privacy_password: '0x73fd9a2cc8c53ed3dd4ed8f4ff157e69'
           username: admin
       changed: true
       commands:
       - snmp-server location Room E, Building 6, Seattle, WA 98134
       failed: false


Example: Verifying the network device configuration has not changed
====================================================================

The following playbook uses the :ansplugin:`arista.eos.eos_l3_interfaces <arista.eos.eos_l3_interfaces#module>` module to gather a subset of the network device configuration (Layer 3 interfaces only) and verifies the information is accurate and has not changed. This playbook passes the results of :ansplugin:`arista.eos.eos_facts <arista.eos.eos_facts#module>` directly to the ``arista.eos.eos_l3_interfaces`` module.


.. code-block:: yaml

  - name: Example of facts being pushed right back to device.
    hosts: arista
    gather_facts: false
    tasks:
      - name: grab arista eos facts
        arista.eos.eos_facts:
          gather_subset: min
          gather_network_resources: l3_interfaces

  - name: Ensure that the IP address information is accurate.
    arista.eos.eos_l3_interfaces:
      config: "{{ ansible_network_resources['l3_interfaces'] }}"
      register: result

  - name: Ensure config did not change.
    assert:
      that: not result.changed

Example: Acquiring and updating VLANs on a network device
==========================================================

This example shows how you can use resource modules to:

#. Retrieve the current configuration on a network device.
#. Save that configuration locally.
#. Update that configuration and apply it to the network device.

This example uses the ``cisco.ios.ios_vlans`` resource module to retrieve and update the VLANs on an IOS device.

1. Retrieve the current IOS VLAN configuration:

.. code-block:: yaml

  - name: Gather VLAN information as structured data
    cisco.ios.ios_facts:
       gather_subset:
        - '!all'
        - '!min'
       gather_network_resources:
       - 'vlans'

2. Store the VLAN configuration locally:

.. code-block:: yaml

  - name: Store VLAN facts to host_vars
    copy:
      content: "{{ ansible_network_resources | to_nice_yaml }}"
      dest: "{{ playbook_dir }}/host_vars/{{ inventory_hostname }}"

3. Modify the stored file to update the VLAN configuration locally.

4. Merge the updated VLAN configuration with the existing configuration on the device:

.. code-block:: yaml

  - name: Make VLAN config changes by updating stored facts on the controller.
    cisco.ios.ios_vlans:
      config: "{{ vlans }}"
      state: merged
    tags: update_config

.. seealso::

  `Network Features in Ansible 2.9 <https://www.ansible.com/blog/network-features-coming-soon-in-ansible-engine-2.9>`_
    A introductory blog post on network resource modules.
  `Deep Dive into Network Resource Modules <https://www.ansible.com/deep-dive-into-ansible-network-resource-module>`_
    A deeper dive presentation into network resource modules.
