Network Programmability and Automation

Executive Summary: The NetDevOps Revolution

For decades, network operations relied on manual, error-prone command-line interfaces (CLI). Enterprise engineers spent thousands of hours typing individual commands on routers and switches line-by-line. In today's hyper-scale cloud environment, manual CLI configuration is no longer viable.

Network Programmability and Automation is the 550-page benchmark reference manual for network engineers, NetDevOps leads, and cloud architects transitioning to API-driven network infrastructure. Spanning 8 comprehensive modules, this handbook covers the entire modern automation stack: from Python CLI scripting with Netmiko and Nornir to Ansible playbook orchestration, YANG data modeling (pyang), NETCONF/RESTCONF RPCs, and CI/CD network config validation with Batfish.

Deep Dive: Core Network Automation Stack

The handbook provides functional Python and Ansible source code blueprints across five network automation pillars:

1. Python Multi-Vendor Automation with Netmiko & TextFSM

Automating SSH connections and parsing unstructured CLI outputs:

• Netmiko Connectors: Handling multi-vendor prompts across Cisco IOS-XE/NX-OS, Arista EOS, and Juniper JunOS devices.
• TextFSM Parsing: Converting raw `show ip interface brief` text outputs into structured Python dictionaries automatically.

2. Infrastructure as Code (IaC) with Ansible & Jinja2

Orchestrating network configurations idempotently at scale:

• Ansible Playbooks: Rendering Jinja2 templates dynamically using host inventory variables (`hosts.yml`) and applying declarative state updates.

3. Programmatic API Access: NETCONF XML & RESTCONF JSON

Replacing CLI scraping with structured, machine-readable API protocols:

• NETCONF RPCs (`ncclient`): Sending XML payloads over SSH to query and modify running data stores (``, ``).

Field Engineering: Python Netmiko Multi-Vendor Script

Chapter 2 of the handbook provides practical Python source code for automating multi-vendor router backups and configuration pushes:

from netmiko import ConnectHandler
import json

devices = [
    {
        'device_type': 'cisco_ios',
        'host': '192.168.10.1',
        'username': 'admin',
        'password': 'SecurePassword123',
    },
    {
        'device_type': 'arista_eos',
        'host': '192.168.10.2',
        'username': 'admin',
        'password': 'SecurePassword123',
    }
]

config_commands = [
    'interface GigabitEthernet0/1',
    'description Configured by MMN NetDevOps Automation Engine',
    'no shutdown'
]

for dev in devices:
    print(f"[*] Connecting to {dev['host']} ({dev['device_type']})...")
    net_connect = ConnectHandler(**dev)
    
    # Execute Config Push
    output = net_connect.send_config_set(config_commands)
    print(f"[+] Config Pushed to {dev['host']}:\n{output}")
    
    # Save Running Configuration
    net_connect.save_config()
    net_connect.disconnect()

from ncclient import manager
import xml.dom.minidom

router_info = {
    'host': '192.168.10.1',
    'port': 830,
    'username': 'admin',
    'password': 'SecurePassword123',
    'hostkey_verify': False
}

netconf_filter = """

  

"""

with manager.connect(**router_info) as m:
    # Execute NETCONF XML RPC
    response = m.get_config(source='running', filter=netconf_filter)
    xml_doc = xml.dom.minidom.parseString(response.xml)
    print(xml_doc.toprettyxml())

Complete Table of Contents & Module Syllabus

• Module 01 The Network Automation Paradigm & Modern Architecture

  Pages 1–65
  Transitioning from CLI to NetDevOps, software-defined networking concepts, and setting up Python virtual environments.
• Module 02 Python Foundations for Network Engineers: Netmiko & TextFSM

  Pages 66–135
  Multi-vendor SSH automation with Netmiko, error handling, TextFSM parsing, and Genie structured output conversion.
• Module 03 Scalable Concurrency Frameworks: Nornir & Async I/O

  Pages 136–200
  Multi-threaded inventory management with Nornir, writing custom Nornir tasks, and high-speed parallel configuration execution.
• Module 04 Infrastructure as Code (IaC) with Ansible & Jinja2 Templating

  Pages 201–270
  Writing idempotent Ansible playbooks, host inventories, Jinja2 template rendering, and dry-run configuration diffs (`--check --diff`).
• Module 05 YANG Data Modeling: Schema Definition & Validation (pyang)

  Pages 271–340
  YANG data modeling fundamentals (RFC 6020), validating data schemas with `pyang`, and converting between YANG, XML, and JSON.
• Module 06 Programmatic Device Access: NETCONF XML RPCs & Ncclient

  Pages 341–410
  NETCONF protocol architecture over SSH (port 830), executing `` and `` RPCs using Python's `ncclient`.
• Module 07 Modern HTTP Networking: RESTCONF APIs & OpenAPI Spec

  Pages 411–480
  RESTCONF HTTPS operations (RFC 8040), JSON payload structures, Postman collection testing, and Python `requests` integration.
• Module 08 Network CI/CD Pipelines, Batfish Testing & gNMI Telemetry

  Pages 481–550
  Pre-deployment network validation with Batfish, building GitLab CI pipelines for network configs, and streaming gNMI telemetry.

Who Should Read This Handbook?

This handbook is designed for modern network engineers and NetDevOps architects:

Verified NetDevOps Engineer Reviews

Frequently Asked Questions