Cisco NX-OS Network Automation using Python User Manual

Table of Contents

Cisco NX-OS Network
Automation using Python-0product

Process of using software to automate network provisioning, testing, deployment and network management
To help maximize network efficiency and functionality
Networks are complex and bulky in nature
Manual operations – more delays
Automation makes the networks more agile and responsive to changes
Benefits:
Improved operational efficiency
Reduced errors

Cisco NX-OS Network Automation using
Python-1

Cisco NX-OS Network Automation using
Python-2

It’s a set of tools to deploy, manage and troubleshoot a network device
Network engineer perspective – interacting with a device or group of devices
Software developer perspective – abstracting the network. Seeing the whole network as a single device and manipulating it with software

APIs are mechanisms used to communicate with applications and other software.
An API may perform different functions based on where they are located in the flow
Used to communicate with various components of the network through software
APIs are usually RESTful APIs

An API that uses REST is often referred to a RESTful API
RESTful APIs use Hypertext Transfer Protocol (HTTP) methods to gather and manipulate data.

HTTP STATUS

CODE

| RESULT| COMMON REASON
---|---|---
200| Ok| Using GET or POST to exchange data with

an API

API call

403| Forbidden| Access not granted based on supplied

credentials

404| Not Found| Page at HTTP URL location does not exist

or is hidden

NAPALM – Network automation and programmability abstraction layer with multi-vendor support
Provides functions that allows:
Configuration operations (commit or rollback)
Retrieve state data from network devices
Contains methods to establish connection to network devices
Can work in conjunction with automation tools – Ansible
Has support for various network OS:
IOS, IOS-XR, NX-OS, JunOS, EOS, etc.

Replace – Allows users to replace the existing running configuration with an entirely new configuration.
Merge – Allows users to merge configuration changes from a file to the running configuration on the device.
Compare – Compare the newly proposed configuration with the existing one. Only applies to replace operation and not for merge operation.
Discard – Resets the merge configuration file to an empty file. Thus, not allowing the new configuration to be applied on the device.
Commit – Commits the proposed configuration to the network device. In other words, used to deploy a staged configuration.
Rollback – Rollback (revert back) the running configuration to the saved configured prior to the last commit.

Jinja is a modern templating language for Python – Modelled after Django templates
Allows user to easily interact with Python program
Use data to quickly generate dynamic content
Benefits:
Template inheritance
Optimal just-in-time compilation
Easy debuggability
Configurable syntax
Commonly used with web frameworks such as Flask
Configuration management tools – Ansible, Nornir, etc.

Cisco NX-OS Network Automation using
Python- Nornir Overview

Python based automation framework
Manage network and host inventory and provide common framework to write plugins for the network devices and hosts
Requires minimum Python version 3.6.2
Multi-threaded – Defaults to 20 worker threads
Initialized using config file – references couple other files
Host inventory file
Group file
All these files are written in YAML format

Python or Golang (Gornir)
Reuse existing libraries – napalm, netmiko
Quick host filtering based on any attribute or combination of attributes
Very fast due to use of threads
Can be used to build highly flexible and extensible automation tools using Flask, Django, etc.
Automatically performs caching and closes open connections