Ansible Limit When Using Netbox as Inventory

I’m currently using Ansible to template a large and growing number of devices for an ISP that I’m working for. The last part of the process is to use Netbox as a source of truth to write the configs using Jinja2 templates. The work is done as part of a CI/CD pipeline, and runs on a specific Gitlab Runner instance – finally the config is pre-staged onto the device’s filesystem to be checked by a engineer before deployment.

I’ve been finding the growing list of hosts a bit hard work, and, seemingly undocumented in the Netbox docs is how to put a site-specific limit on the playbook run. This is easily done in regular Ansible by using .ini-style host file groups like this:

[siteA]
sitea-router001
sitea-router002

[siteB]
siteb-router001
siteb-router002

You can then do ‘ansible-playbook -l siteB’ to restrict what gets generated. How you do this when Netbox is the source of inventory is less clear.

It turns out that sites are pre-pended in Netbox with the string ‘sites_’. So, in your dynamic inventory file (in my case, called nb-inventory.yml) you need to tell it to group hosts by site by including the sites keyword under the group_by section:

plugin: netbox.netbox.nb_inventory
api_endpoint: https://YOURURLHERE
token: YOURTOKENHERE
validate_certs: False
config_context: False
group_by:
  - device_roles
  - sites

query_filters:
  - has_primary_ip: 'true'

compose:
  ansible_network_os: platform.slug

Then, the command to retrieve hosts by site is:

ansible-playbook main.yml -i nb-inventory.yml -l sites_sitea

This should return something like the following:

    "sites_sitea": {
        "hosts": [
            "sitea-router001",
            "sitea-router002"
        ]
    }

Et voila…