DNA Center Inventory Plugin

DNA Center Inventory Plugin allows you to utilize the network discovery
capabilities of Cisco's DNA Center controller as a source of inventory for
Ansible Playbooks.

Change Log

• [04/12/2022] Updated plugin dependencies to DNA Center SDK for proper abstraction
• [04/12/2022] Fixed issue with large deployments in which DNA Center API result is limited to 500 records

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Functionality

The DNA Center Inventory plugin will gather all groups (sites) and inventory devices from DNA Center. The hosts are associated with appropriate sites in the hierarchy.

The following host_vars are associated with the network devices:

• ansible_connection : network_cli for ios and nxos devices
• ansible_become_method : for ios and nxos types. (enable)
• ansible_become : yes for ios and nxos types.
• ansible_host : using the managementIpAddress from DNA Center - conditionally mapped based on control file dna_center.yml. (see note at the bottom)
• ansible_network_os : derived from os below and required for Ansible network_cli connection plugin
• os : network operating system as stored in DNA Center's softwareType
• version : network operating system version as stored in DNA Center's softwareVersion
• id : managed network device unique identifier used by DNA Center. Device Id (or UUID) can be used for filtering and scoping in DNAC API calls

Getting Started

Follow the instructions below to install the Ansible Inventory Plugin for Cisco DNA Center on your Ansible control node.

Requirements

To utilize the inventory plugin your environment would need to include the following elements:

• Ansible - (tested 2.12.3)
• Python - min 3.5 (tested 3.10.3)
• Cisco DNA Center - tested 2.3.2. Refer to DNA Center SDK for supported DNAC Versions: https://dnacentersdk.readthedocs.io/en/latest/api/intro.html
• Python requests module
• Python DNA Center SDK DNACenterAPI module

Setup

Follow these steps to prepare your environment appropriately to consume the inventory plugin.

STEP 1. Clone or fork this repo and install Python modules

vagrant@ubuntu-xenial:~$ git clone https://github.com/jandiorio/ansible-dnac-inventory-plugin
Cloning into 'ansible-dnac-inventory-plugin'...
remote: Enumerating objects: 101, done.
remote: Counting objects: 100% (101/101), done.
remote: Compressing objects: 100% (47/47), done.
remote: Total 101 (delta 49), reused 101 (delta 49), pack-reused 0
Receiving objects: 100% (101/101), 32.73 KiB | 0 bytes/s, done.
Resolving deltas: 100% (49/49), done.
Checking connectivity... done.

pip3 install -r requirements.txt

STEP 2. Place the files in the appropriate location or update the environment
variable with the location

vagrant@ubuntu-xenial:~$ cp -r ansible-dnac-inventory-plugin/inventory_plugins dna_3_legacy/

STEP 3. Enable the inventory plugin

Most Ansible inventory plugins are disabled by default so the must be enabled
to be used.

The Ansible documentation will explain how to consume inventory plugins.

https://docs.ansible.com/ansible/latest/plugins/inventory.html

export ANSIBLE_INVENTORY_ENABLED=dna_center

export ANSIBLE_INVENTORY_PLUGINS=$(PWD)

The alternate way of configuring these options using the ansible.cfg file:

1. Add the plugin name to the list of enabled plugins. The order determines the execution order.

[inventory]
enable_plugins = host_list, script, yaml, ini, auto, dna_center

2. Add the path to the inventory_plugins setting in the defaults section. (use a colon : to separate multiple entries)

[defaults]
inventory_plugins = /Users/andiorij/development/dnac_inventory_plugin

https://docs.ansible.com/ansible/latest/reference_appendices/config.html

STEP 4. Update the plugin configuration file inventory_plugins/dna_center.yml

---
plugin: dna_center
host: 'dnac-ip-address.local'
dnac_version: '2.2.3.3'
validate_certs: False
use_dnac_mgmt_int: False
username: '{{ your_dnac_username }}'
password: '{{ your_dnac_pwd }}'
toplevel:

STEP 5. Execute the example below to test functionality

vagrant@ubuntu-xenial:~/dna_3_legacy$ ansible-inventory -i inventory_plugins/ --graph

/home/vagrant/.local/lib/python2.7/site-packages/urllib3/connectionpool.py:847: InsecureRequestWarning: Unverified HTTPS request is being made. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#ssl-warnings
  InsecureRequestWarning)
  
@all:
  |--@central:
  |  |--@maryland_heights:
  |  |  |--@atc56:
  |  |  |  |--dna-3-a1.campus.wwtatc.local
  |  |  |  |--dna-3-a2.campus.wwtatc.local
  |  |  |  |--dna-3-d1.campus.wwtatc.local
  |  |  |  |--dna-3-d2.campus.wwtatc.local
  |--@east:
  |--@ungrouped:
  |--@west:

Example Usage

To test if your inventory source is functioning correctly, execute the command
below.

ansible-inventory --graph

ansible-inventory --list

ansible-playbook -i inventory_plugins/ samples/sample_playbook.yml

Supporting Collateral

• Ansible Inventory Plugin Overview Slides

References

https://github.com/ansible/ansible/blob/devel/lib/ansible/plugins/inventory

https://docs.ansible.com/ansible/latest/user_guide/intro_dynamic_inventory.html#dynamic-inventory

https://docs.ansible.com/ansible/latest/dev_guide/developing_inventory.html

https://dnacentersdk.readthedocs.io/en/latest/installation.html

https://dnacentersdk.readthedocs.io/en/latest/api/api.html

Observed Issues

The inventory plugin builds the inventory from DNA Center includinig group mappings and some limited host variable mappings seen here:

"dna-3-d2.campus.wwtatc.local": {
                "ansible_become": "yes", 
                "ansible_become_method": "enable", 
                "ansible_connection": "network_cli", 
                "ansible_host": "192.168.19.3",
                "ansible_network_os": "ios", 
                "os": "IOS-XE", 
                "version": "16.9.1"
            }

Issue Observed - mapping of ansible_host is controlled by the plugin control file dna_center.yml. if this value is mapped, that address will be used for connection. It must be reachable. In the lab environment, this was behind a NAT and not reachable directly.

Issue Observed - if ansible_host is not mapped, the inventory_hostname must be resolvable by the ansible control mode.

Issue Observed - when executing on OSX Monterey, following error message observed:

objc[13508]: +[__NSCFConstantString initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug.

Workaround: set environment variable prior to execution

export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES

Issue Observed - If DNA Center Site Hierarchy contains site names starting with a number, plugin outputs a warning message

[WARNING]: Invalid characters were found in group names but not replaced, use -vvvv to see details

Author

Jeff Andiorio - World Wide Technology

Igor Manassypov - Cisco Systems, imanassy@cisco.com