Book Image

Network Automation Cookbook

By : Karim Okasha
Book Image

Network Automation Cookbook

By: Karim Okasha

Overview of this book

Network Automation Cookbook is designed to help system administrators, network engineers, and infrastructure automation engineers to centrally manage switches, routers, and other devices in their organization's network. This book will help you gain hands-on experience in automating enterprise networks and take you through core network automation techniques using the latest version of Ansible and Python. With the help of practical recipes, you'll learn how to build a network infrastructure that can be easily managed and updated as it scales through a large number of devices. You'll also cover topics related to security automation and get to grips with essential techniques to maintain network robustness. As you make progress, the book will show you how to automate networks on public cloud providers such as AWS, Google Cloud Platform, and Azure. Finally, you will get up and running with Ansible 2.9 and discover troubleshooting techniques and network automation best practices. By the end of this book, you'll be able to use Ansible to automate modern network devices and integrate third-party tools such as NAPALM, NetBox, and Batfish easily to build robust network automation solutions.
Table of Contents (15 chapters)

Configuring L2 VLANs on IOS devices

In this recipe, we will outline how to configure L2 VLANs on Cisco IOS devices, as per the network topology discussed in the introduction to this chapter. We will outline how to declare VLANs as Ansible variables, and how to use suitable Ansible modules to provision these VLANs on the network.

Getting ready

We will be building on the previous recipes discussed in this chapter to continue to configure the L2 VLANs on all the LAN devices within our sample topology.

How to do it...

  1. Update the group_vars/lan.yml file with the VLAN definition, as outlined in the following code:
$ cat group_vars/lan.yaml

- name: Data
vlan_id: 10
- name: Voice
vlan_id: 20
- name: Web
vlan_id: 100
  1. Update the pb_build.yml playbook with the following task to provision the VLANs:
  - name: "P1T4: Create L2 VLANs"
vlan_id: "{{ item.vlan_id }}"
name: "{{ }}"
loop: "{{ vlans }}"
tags: vlan

How it works...

In the group_vars/lan.yml file, we define a vlans list data structure that holds the VLAN definition that we need to apply to all our core and access switches. This variable will be available for all the core and access switches, and Ansible will use this variable in order to provision the required VLANs on the remote devices.

We use another declarative module, ios_vlan, which takes the VLAN definition (its name and the VLAN ID) and configures these VLANs on the remote managed device. It pulls the existing configuration from the device and compares it with the list of devices that need to be present, while only pushing the delta.

We use the loop construct to go through all the items in the vlans list, and configure all the respective VLANs on all the devices.

After running this task on the devices, the following is the output from one of the access switches:

access01#sh vlan
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Et1/0, Et1/1, Et1/2, Et1/3
10 Data active Et0/3
20 Voice active
100 Web active