Network Automation Cookbook

Proven and actionable recipes to automate and manage network devices using Ansible

Karim Okasha

• Publisher: Packt Publishing
• Year: 2020
• ISBN:
  9781789951875
• Edition: 1
• Topic: Ciencia de la computación
• Subtopic: Programación en Python

Take your network automation skills to the next level with practical recipes on managing network devices from a variety of vendors like Cisco, Juniper, and Arista

Key Features

• Use Ansible to automate network infrastructure with the help of step-by-step instructions
• Implement network automation best practices to save cost, avoid critical errors, and reduce downtime
• Deliver a robust automation framework by integrating Ansible with NAPALM, NetBox, and Batfish

Book Description

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.

What you will learn

• Understand the various components of Ansible
• Automate network resources in AWS, GCP, and Azure cloud solutions
• Use IaC concepts to design and build network solutions
• Automate network devices such as Cisco, Juniper, Arista, and F5
• Use NetBox to build network inventory and integrate it with Ansible
• Validate networks using Ansible and Batfish

Who this book is for

This Ansible network automation book is for network and DevOps engineers interested in automating complex network tasks. Prior understanding of networking and basic Linux knowledge is required.

Automating Juniper Devices in the Service Providers Using Ansible

In this chapter, we will outline how to automate Juniper devices running the Junos OS software in a typical service provider (SP) environment. We will explore how to interact with Juniper devices using Ansible, and how to provision different services and protocols on Juniper devices using various Ansible modules. We will base our illustration on the following sample network diagram of a basic SP network:

The following table outlines the devices in our sample topology and their respective management Internet Protocols (IPs):

Device	Role	Vendor	Management (MGMT) Port	MGMT IP
mxp01	P Router	Juniper vMX 14.1	fxp0	172.20.1.2
mxp02	P Router	Juniper vMX 14.1	fxp0	172.20.1.3
mxpe01	PE Router	Juniper vMX 14.1	fxp0	172.20.1.4
mxpe02	PE Router	Juniper vMX 17.1	fxp0	172.20.1.5

The main recipes covered in this chapter are as follows:

• Building the network inventory
• Connecting and authenticating to Juniper devices
• Enabling the Network Configuration Protocol (NETCONF) on Junos OS devices
• Configuring generic system options on Juniper devices
• Configuring interfaces on Juniper devices
• Configuring Open Shortest Path First (OSPF) on Juniper devices
• Configuring Multiprotocol Label Switching (MPLS) on Juniper devices
• Configuring the Border Gate Protocol (BGP) on Juniper devices
• Deploying configuration on Juniper devices
• Configuring the Layer 3 virtual private network (L3VPN) service on Juniper devices
• Gathering Juniper device facts using Ansible
• Validating network reachability on Juniper devices
• Retrieving operational data from Juniper devices
• Validating the network state using PyEZ operational tables

Technical requirements

The code files for this chapter can be found here: https://github.com/PacktPublishing/Network-Automation-Cookbook/tree/master/ch3_junos.

The following are the software releases on which this chapter is based:

• Ansible machine running CentOS 7
• Ansible 2.9
• Juniper Virtual MX (vMX) running Junos OS 14.1R8 and Junos OS 17.1R1 release

Check out the following video to see the Code in Action:
https://bit.ly/3ajF4Mp

Building the network inventory

In this recipe, we will outline how to build and structure the Ansible inventory to describe the sample SP network setup outlined previously. The Ansible inventory is a pivotal part in Ansible, as it defines and groups devices that should be managed by Ansible.

Getting ready

We create a new folder that will host all the files that we will create in this chapter. The new folder is named ch3_junos.

How to do it...

1. Inside the new folder, ch3_junos, we create a hosts file with the following content:

$ cat hosts

[pe]
mxpe01 Ansible_host=172.20.1.3
mxpe02 Ansible_host=172.20.1.4

[p]
mxp01 Ansible_host=172.20.1.2
mxp02 Ansible_host=172.20.1.6

[junos]
mxpe[01:02]
mxp[01:02]
 
[core:children]
pe
p

2. Create an Ansible.cfg file, as shown in the following code:

$ cat Ansible.cfg
 
 [defaults]
 inventory=hosts
 retry_files_enabled=False
 gathering=explicit
 host_key_checking=False

How it works...

We build the Ansible inventory using the hosts file and we define multiple groups in order to group the different devices in our network infrastructure, as follows:

• We create the PE group, which references all the MPLS Provider Edge (PE) nodes in our topology.
• We create the P group, which references all the MPLS Provider (P) nodes in our topology.
• We create the junos group, which references all the devices running Junos OS as the OS.
• We create the core parent group, which references both the PE and P groups.

Finally, we create the Ansible.cfg file and configure it to point to our hosts file, to be used as the Ansible inventory file. We set the gathering to explicit in order to disable the setup module, which runs by default to discover facts for the managed hosts. Disabling the setup module is mandatory since the setup module will fail when run against network devices.

We can validate that our Ansible inventory is structured and written correctly by typing the following command:

$ Ansible-inventory --list
 
 "all": {
 "children": [
 "core",
 "junos",
 "ungrouped"
 ]
 },
 "core": {
 "children": [
 "p",
 "pe"
 ]
 },
 "junos": {
 "hosts": [
 "mxp01",
 "mxp02",
 "mxpe01",
 "mxpe02"
 ]
 },
 "p": {
 "hosts": [
 "mxp01",
 "mxp02"
 ]
 },
 "pe": {
 "hosts": [
 "mxpe01",
 "mxpe02"
 ]
 }

Connecting and authenticating to J...