Changing Network Configurations or State

You should have completed the Ansible for Networking Engineers course by now. If you haven't done that, please do it now, and make sure you're thoroughly familiar with these sections:

• Jinja2 (including DMPVN case study)
• Ansible Networking Modules - Managing configurations
• Using NAPALM with Ansible

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In this tutorial David Barroso explains the basics of network device configurations based on abstracted data models, including data derived from a back-end database.

Using Ansible device configuration modules to change parts of device configuration seems easy enough (as does replacing the whole device configuration with NAPALM)... but as always, you'll encounter numerous showstoppers and caveats when trying to use them.

This section describes the principles of managing network device configurations, the caveats of using Ansible device configuration modules, and the details of recovering from failures using configuration rollback mechanisms.

The VLAN Service Provisioning case study starts with simple configuration changes based on service data model, and slowly introduces more complex topics like data model transformation, service decomissioning, and post-deployment validation.

Every network automation solution needs an authoritative source of truth. This section describes how you can use IPAM tools (using NetBox as a sample tool to illustrate the concepts) to provide the source of truth for IP address assignments, IP subnet allocation, VLAN numbering, and even shared secrets like RADIUS keys.

Zero-Touch Provisioning (ZTP) is an obvious candidate for an network automation, as the impact of incorrectly-provisioned new devices is usually minimal. However, even though every vendor claims to have a ZTP solution, building an end-to-end system integrated with your workflow remains a hard problem.

In his presentation Patrick Ogenstad explained the basics of ZTP, described typical ZTP components, presented a solution you can use to build dynamic device configuration files, and answered tons of attendee questions.

Before you start working on solving the hands-on exercise for this module you might want to spend some time exploring some of my infrastructure and service provisioning Ansible playbooks.

We got to the point where you'll build a full-blown solution using the data model you developed. Use it to generate device configurations, deploy them to your lab devices, and validate that the services have been correctly deployed.

If you want to know more about NAPALM, the multi-vendor library heavily used in this part of the course, watch the NAPALM presentation from NANOG64 and listen to several podcasts we did with David Barroso and Elisa Jasinska.