About the Author ....................................................................................................xix
About the Technical Reviewer ................................................................................xxi
Acknowledgments ................................................................................................xxiii
Introduction ...........................................................................................................xxv
■■Chapter 1: Introduction to Python Network Automation ....................................... 1
Laying the Foundation ...................................................................................................... 1
Exploring Your Skills and Prerequisites ............................................................................ 2
General Competencies of Three Main IT Domain Group ......................................................................... 3
Comparative Analysis of IT Engineers’ Responsibilities ......................................................................... 6
Python and Network Automation Studies ....................................................................... 10
Why Do People Want to Learn Python? ................................................................................................. 10
What Do I Need to Study Network Automation Using Python? ....................................... 12
Hardware: Minimum Specifications for Laptop or PC ..................................................... 13
Software Requirements .................................................................................................. 14
Building a Network Automation Development Environment Using GNS3 ....................... 16
Downloading Supplementary Guides and Source Code ................................................. 20
Summary ........................................................................................................................ 21
Storytime 1: Mega Speed Shoe Factory ......................................................................... 21
■■Chapter 2: Learn Python Basics on Windows ...................................................... 23
“Hello, World!” and print( ) Function in Interactive Mode ............................................... 24
Preparing for the Python Exercises ................................................................................ 27
Understanding Data Types ....................................................................................................................28
Indentation and Code Blocks ................................................................................................................30
Commenting .........................................................................................................................................31
Python Naming Convention ..................................................................................................................32
Doing the Python Exercises ............................................................................................ 33
Variables and Strings ..................................................................................................... 34
Exercise 2-1: Create Variables and Assign Various Data Types ............................................................ 34
Exercise 2-2: Create Variables and Use the print( ) Function to Print Output ........................................ 35
Exercise 2-3: Use Abbreviated Variable Assignment ............................................................................ 36
Exercise 2-4: Enter a String, Escape Character Backslash (\), and type( ) Function ............................. 36
Exercise 2-5: Determine If a Variable Is a Container, a Tag, or a Pointer .............................................. 38
Exercise 2-6: Use String Indexing .........................................................................................................39
Exercise 2-7: Understand Variable Assignment Errors ......................................................................... 39
Exercise 2-8: Avoid “SyntaxError: EOL While Scanning String Literal” ................................................. 40
Exercise 2-9: Avoid “NameError: name ‘variable_name’ is not defined” .............................................. 40
Exercise 2-10: Avoid “SyntaxError: invalid syntax” ............................................................................... 41
Exercise 2-11: Avoid “TypeError: ‘str’ object is not callable” ................................................................ 41
Exercise 2-12: Add Multiline Comments with Triple Quotation Marks .................................................. 43
Exercise 2-13: Use \ as an Escape Character to Remove Special Character Meanings ....................... 44
Exercise 2-14: Enter (Inject) Values/Strings in a String Using %s ........................................................ 44
Printing, Concatenating, and Converting Strings ............................................................ 45
Exercise 2-15: Use the print( ) and len( ) Functions to Create a Simple Function ................................. 45
Exercise 2-16: Use the lower( ) and upper( ) String Methods ............................................................... 46
Exercise 2-17: Perform String Concatenation and Use the str( ) Method ............................................. 46
Exercise 2-18: Learn to Change a String Using Curly Brackets and .format( ) ..................................... 47
Exercise 2-19: Adjust the Text Position with Curly Brackets and .format( ) .......................................... 48
Exercise 2-20: Adjust the Number of Decimal Places .......................................................................... 49
Exercise 2-21: Ask for and Receive User Input with input( ) ................................................................. 49
Exercise 2-22: Change a Word or Characters in a String ...................................................................... 50
Recap: Variables and Strings ................................................................................................................51
Numbers and Arithmetic Operators ................................................................................ 52
Exercise 2-23: Use Arithmetic Operators ..............................................................................................52
Exercise 2-24: Understand Integers vs. Strings ...................................................................................53
Recap: Arithmetic Operators .................................................................................................................53
Booleans and Relational Operators ................................................................................ 54
Exercise 2-25: Use Booleans ................................................................................................................54
Exercise 2-26: Use Relational Operators ..............................................................................................55
Exercise 2-27: Use Boolean Expressions to Test True or False ............................................................. 55
Exercise 2-28: Use Logical (Membership) Operators ............................................................................ 56
Exercise 2-29: Change the Order of Operation with ( ) ......................................................................... 56
Control Statements: if, elif, and else ............................................................................... 56
Exercise 2-30: Use if and else ..............................................................................................................57
Exercise 2-31: Use if, elif, and else .......................................................................................................57
Exercise 2-32: Write Code with if, elif, and else .................................................................................... 58
Recap: Boolean and Conditionals .........................................................................................................59
Functions ........................................................................................................................ 59
Exercise 2-33: Defining a Function .......................................................................................................60
Exercise 2-34: Assign Default Values to a Function .............................................................................. 60
Exercise 2-35: Define Hello and Goodbye Functions ............................................................................ 61
Exercise 2-36: Use the Odd or Even Function ....................................................................................... 62
Exercise 2-37: Nest a Function Within a Function ................................................................................ 62
Recap: Functions ..................................................................................................................................63
Lists ................................................................................................................................ 63
Exercise 2-38: Create a List and Index Items ....................................................................................... 63
Exercise 2-39: Use append, extend, and insert in a List ....................................................................... 64
Slicing ............................................................................................................................ 65
Exercise 2-40: Slice a List ....................................................................................................................65
Exceptions and Error Handling ....................................................................................... 66
Exercise 2-41: Avoid a ValueError Error ................................................................................................66
Exercise 2-42: Handle Errors with try and except in a List ................................................................... 66
Exercise 2-43: Find an Index of an Item in a List with the Customized Exception ............................... 68
Practicing Lists .....................................................................................................................................69
Exercise 2-44: Practice a List ...............................................................................................................69
Using for Loops and while Loops ................................................................................... 71
Exercise 2-45: Use the for Loop’s upper( ) and capitalize( ) Methods ................................................... 71
Exercise 2-46: Use the while Loop and len( ) Function ......................................................................... 71
Sorting and Ranges ........................................................................................................ 72
Exercise 2-47: Use sort( ) vs. sorted( ) in a List ..................................................................................... 72
Exercise 2-48: Link Two Lists ...............................................................................................................72
Exercise 2-49: Find the List Length Using the len( ) Function ............................................................... 73
Exercise 2-50: Use range( ) and the for Loop ........................................................................................ 73
Exercise 2-51: Use the String List for loop( ) and range( ) with Arguments .......................................... 74
Recap: Lists and Loops .........................................................................................................................75
Tuples ............................................................................................................................. 76
Exercise 2-52: See Some Basic Tuple Examples .................................................................................. 76
Exercise 2-53: Convert a Tuple to a List ...............................................................................................76
Exercise 2-54: Determine Whether a Tuple Immutable ......................................................................... 77
Exercise 2-55: Convert a Tuple to a List and a List to a Tuple ............................................................... 78
Exercise 2-56: Use a for Loop in a Tuple ...............................................................................................78
Exercise 2-57: Assign Multiple Variables to a Tuple ............................................................................. 79
Exercise 2-58: Create a Simple Tuple Function .................................................................................... 79
Exercise 2-59: Use Tuples as List Elements ......................................................................................... 80
Recap: Tuples ........................................................................................................................................80
Dictionaries .................................................................................................................... 81
Exercise 2-60: Understand Dictionary Basics .......................................................................................81
Exercise 2-61: Avoid a Dictionary TypeError and Convert Two Lists to a Single Dictionary .................. 82
Exercise 2-62: Use Keys to Print Values from a Dictionary ................................................................... 82
Exercise 2-63: Change a Dictionary Value ............................................................................................83
Exercise 2-64: Add a New Set of Keys and Values to a Dictionary ....................................................... 83
Exercise 2-65: Find the Number of Dictionary Elements ...................................................................... 84
Exercise 2-66: Delete Dictionary Keys and Values ............................................................................... 84
Exercise 2-67: Write a Python Script with a Dictionary ........................................................................ 84
Exercise 2-68: Use a Dictionary for a Loop and Formatting ................................................................. 85
Recap: Dictionaries ...............................................................................................................................86
Handling Files ................................................................................................................. 87
Exercise 2-69: Read and Display Hosts File from Your PC .................................................................... 87
Exercise 2-70: Open and Close Hosts Files .......................................................................................... 88
Exercise 2-71: Create Code to Close a File in Two Ways ...................................................................... 89
Exercise 2-72: Create a Text File, and Read, Write, and Print ............................................................... 90
Exercise 2-73: Use rstrip( ) or lstrip( ) to Remove Whitespace .............................................................. 93
Exercise 2-74: Python File Mode Exercise: Use r Mode ........................................................................ 94
Exercise 2-75: Python File Mode Exercise: Use r+ Mode ..................................................................... 95
Exercise 2-76: Python File Mode Exercise: Use a Mode ....................................................................... 96
Exercise 2-77: Python File Mode Exercise: Use a+ Mode ..................................................................... 99
Exercise 2-78: Python File Mode Exercise: Use w Mode ...................................................................... 99
Exercise 2-79: Python File Mode Exercise: Use w+ Mode .................................................................. 100
Exercise 2-80: Python File Mode Exercise: Use x Mode ..................................................................... 101
Exercise 2-81: Python File Mode Exercise: Use x Mode ..................................................................... 102
Exercise 2-82: Open a Byte File in Python ..........................................................................................103
Exercise 2-83: Handle Errors with try and except .............................................................................. 104
Recap: Python file Handling Concept ..................................................................................................105
Using Python Modules .................................................................................................. 105
Time Module ................................................................................................................. 106
Exercise 2-84: Import the time Module ..............................................................................................106
Sleep Method ............................................................................................................... 106
Exercise 2-85: Use the time.sleep( ) Function ..................................................................................... 106
Exercise 2-86: Browse a Path Using the sys Module ......................................................................... 107
Exercise 2-87: Add a New Filepath Using the sys Module .................................................................. 108
Exercise 2-88: Check Built-ins and sys.builtin_module ..................................................................... 109
Exercise 2-89: Use a Simple import sys Module in a try and except Exercise ................................... 110
Exercise 2-90: Understand Lambdas by Making a Calculator ............................................................ 111
Recap: Module Concepts ....................................................................................................................112
Summary ...................................................................................................................... 112
■■Chapter 3: More Python Exercises .................................................................... 113
Getting Ready for the Exercises ................................................................................... 113
Exercise 3-1: Concatenate a List and a Tuple into a Single List ......................................................... 114
Exercise 3-2: Use Python as a Calculator ...........................................................................................114
Exercise 3-3: Do Some Basic String format( ) Exercises .................................................................... 114
Exercise 3-4: Ask for a Username ......................................................................................................115
Exercise 3-5: Get a Username: Version 1 ............................................................................................116
Exercise 3-6: Get a Username: Version 2 ............................................................................................117
Exercise 3-7: Get a Username: Version 3 ............................................................................................118
Exercise 3-8: Add a Temporary Filepath, Import ex3_7.py as a Module, and Run the Script .............. 120
Exercise 3-9: Use Commas to Add Spaces Between Strings .............................................................. 120
Exercise 3-10: Practice if; if and else; and if, elif, and else ................................................................ 121
Exercise 3-11: Practice for ~ in range with end=‘ ’ ........................................................................... 122
Exercise 3-12: Practice for ~ in range ................................................................................................123
Exercise 3-13: Practice for line in ~ ...................................................................................................123
Exercise 3-14: Use the split( ) Method ................................................................................................ 124
Exercise 3-15: Practice with lstrip( ), rstrip( ), strip( ), upper( ), lower( ), title( ), and capitalize( ) ........ 124
Exercise 3-16: Create a file and read it four different ways ............................................................... 125
Exercise 3-17: Read and Output Files for a More Detailed Understanding ......................................... 126
Exercise 3-18: Use the getpass( ) Module and User Input .................................................................. 127
Exercise 3-19: Understand the Difference Between Encoding and Decoding .................................... 128
Exercise 3-20: Handle CSV Files in Python with the csv Module ........................................................ 128
Exercise 3-21: Output a CSV File ........................................................................................................132
Exercise 3-22: Find the Price of a Cisco ISR 4331 Router from a CSV File ......................................... 132
Exercise 3-23: Calculate the Total Cost of the Router Purchases: No Module .................................... 133
Exercise 3-24: Calculate the Total Cost of the Router Purchases: Using the csv Module ................... 134
Exercise 3-25: Convert dd-mmm-yy and Calculate the Difference in Days and Then in Years .......... 134
Exploring the Python IDE Environment ......................................................................... 136
Summary ...................................................................................................................... 137
Storytime 2: Machine vs. Human, The First Confrontation ........................................... 138
■■Chapter 4: Introduction to VMware Workstation ............................................... 139
VMware Workstation at a Glance ................................................................................. 139
Type-1 vs. Type-2 Hypervisors ............................................................................................................141
VMware Workstation Pro for a Proof-of-Concept Lab ......................................................................... 142
Before Using VMware Workstation ............................................................................... 142
What’s Next on VMware Workstation 15 Pro? ..................................................................................... 145
VMware Workstation 15 Pro User Console ......................................................................................... 145
Basic Operations of VMware Workstation 15 Pro ......................................................... 146
VMware Workstation Pro: Basic Operations ....................................................................................... 147
VMware Workstation Menu .................................................................................................................149
Virtual Network Adapters ............................................................................................. 152
Virtual Network Editor Overview .........................................................................................................152
Virtual Network Interface Description ................................................................................................155
Revealing Each Virtual Network Interface Types ................................................................................ 159
Summary ...................................................................................................................... 168
■■Chapter 5: Creating an Ubuntu Server Virtual Machine ..................................... 169
Downloading and Installing a Ubuntu Server 20 Image ............................................... 170
Downloading the Ubuntu Server 20.04 LTS Image ....................................................... 171
Installing Ubuntu Server 20.04 LTS .............................................................................. 172
Logging In to a New Ubuntu Server 20 via SSH ........................................................... 196
Customize Ubuntu Server ............................................................................................. 202
Ubuntu VM Customization 1: Enable Root User SSH Login on Ubuntu Server 20.04 .......................... 203
Ubuntu VM Customization 2: Install a Desktop GUI and Other Packages ............................................ 205
Ubuntu VM Customization 3: Enable Root User GUI Access ................................................................ 210
Taking a Snapshot of a Virtual Machine ....................................................................... 214
Cloning a Virtual Machine ............................................................................................. 217
Summary ...................................................................................................................... 222
■■Chapter 6: Creating a CentOS 8 Server Virtual Machine .................................... 223
Downloading and Installing a CentOS 8 Server Image ................................................. 223
Downloading the CentOS 8 Server Image ...........................................................................................224
Installing CentOS 8 Server ..................................................................................................................226
Logging In to a New CentOS 8 Server via SSH ................................................................................... 260
Managing a Network Adapter on Linux ..............................................................................................263
Creating a GNS3 VM by Importing an .ova File ............................................................. 269
Downloading and Installing the GNS3 VM from an .ova File ............................................................... 270
Summary ...................................................................................................................... 274
Storytime 3: The Origin of Hypervisors ......................................................................... 274
■■Chapter 7: Linux Fundamentals ......................................................................... 275
Why Learn Linux? ......................................................................................................... 276
The Beginning of Linux ................................................................................................. 278
Understanding the Linux Environment ......................................................................... 279
Understanding Linux Directories and File Formats ...................................................... 280
vi vs. nano .................................................................................................................... 281
Introduction to vi .................................................................................................................................282
Introduction to nano ...........................................................................................................................293
Linux Basic Administration ........................................................................................... 306
Changing the Hostname .....................................................................................................................306
Linux Basic File and Directory Commands ......................................................................................... 309
Linux File and Directory Exercises ..................................................................................................... 311
Summary ...................................................................................................................... 327
■■Chapter 8: Linux Basic Administration .............................................................. 329
Information on Linux: Kernel and Distribution Version ................................................. 329
Information on Linux: Use the netstat Command to Validate TCP/UDP Ports ............... 332
Installing TFTP, FTP, SFTP, and NTP Servers .................................................................. 339
FTP Server Installation ....................................................................................................................... 340
Installing the SFTP Server ..................................................................................................................346
Installing the TFTP Server ...................................................................................................................350
Installing the NTP Server ....................................................................................................................355
Linux TCP/IP Troubleshooting Exercise ......................................................................... 359
Summary ...................................................................................................................... 364
Storytime 4: Becoming a Savvy Linux Administrator, Perhaps Every IT
Engineer’s Dream? ....................................................................................................... 364
■■Chapter 9: Regular Expressions for Network Automation ................................. 367
Why Regex? .................................................................................................................. 368
To re or Not to re .................................................................................................................................369
Studying Regular Expressions Using Python ................................................................ 371
Method 1: Using Notepad++ ..............................................................................................................372
Method 2: Using the Linux Shell .........................................................................................................374
Regular Expression Breakdown: [A-Z]{3}\d{4}[/]\w+ .......................................................................... 375
Method 3: Using the Internet to Study Regular Expressions .............................................................. 375
Regex Operation: The Basics ........................................................................................ 376
Character Class ([]) .............................................................................................................................378
Dot (.): Single Character Match ...........................................................................................................379
Asterisk (*): Repetition ........................................................................................................................380
Plus (+): Repetition .............................................................................................................................380
{m, n}: Repetition ................................................................................................................................380
Python’s re Module ....................................................................................................... 382
Python re String Methods ...................................................................................................................383
Match Object Method .........................................................................................................................387
Compile Options ........................................................................................................... 388
re.DOTALL (re.S) ..................................................................................................................................389
re.IGNORECASE (re.I) ...........................................................................................................................389
re.MULTILINE (re.M) ............................................................................................................................ 390
re.VERBOSE (re.X) ...............................................................................................................................391
\: Confusing Backslash Character ................................................................................ 392
Regular Expressions: A Little Revision Plus More ........................................................ 393
More Metacharacters .........................................................................................................................393
Lookahead and Lookbehind Assertions .............................................................................................. 403
Lookahead, Lookbehind, and Noncapturing group ............................................................................. 403
Practice More Lookarounds ................................................................................................................405
Lookaround Application Examples ......................................................................................................407
sub Method: Substituting Strings ................................................................................. 409
Substitute Strings Using sub ..............................................................................................................410
Using sub and \g to Swap Positions ...................................................................................................410
Insert a Function in sub Method .........................................................................................................411
Summary ...................................................................................................................... 413
■■Chapter 10: GNS3 Basics ................................................................................... 415
GNS3 at a Glance .......................................................................................................... 415
Installing GNS3 for the First Time ................................................................................. 417
Downloading the GNS3 Installation File ..............................................................................................417
GNS3 Installation and Setup ......................................................................................... 418
GNS3 Installation ................................................................................................................................418
GNS3 Setup Procedures .....................................................................................................................418
Getting Familiar with GNS3 .......................................................................................... 424
GNS3 Menus and GUI ..........................................................................................................................424
Gracefully Shutting Down GNS3 and GNS3 VM ................................................................................... 426
Starting GNS3 as an Administrator .....................................................................................................428
Using GNS3 for the First Time: Cisco IOS and Windows Lab ........................................ 429
Cisco IOS Software License and Downloading an Older Cisco IOS ..................................................... 430
Decompressing Cisco IOS for GNS3 Use .............................................................................................431
Installing Cisco IOS on the GNS3 VM ............................................................................ 442
Creating an IOS Lab Topology on GNS3 and Connecting to the Internet ...................... 454
Installing the Microsoft Loopback Adapter ................................................................... 462
Accessing GNS3 Network Devices Using MS Loopback ..................................................................... 469
Configuring the GNS3 IOS Router Using a Python Script from the Windows
Host PC ......................................................................................................................... 478
Cisco IOS and GNS3 Appliance Lab .............................................................................. 482
Importing and Installing the GNS3 Linux Appliance Server ................................................................ 482
Manually Assigning IP Address to GNS3 Linux Appliance Server ....................................................... 486
Using the GNS3 Appliance Linux’s Python to Manage R1 ................................................................... 487
Summary ...................................................................................................................... 489
■■Chapter 11: Cisco IOS Labs ................................................................................ 491
Cisco IOS and the Linux VM Lab ................................................................................... 491
Creating a New GNS3 Project for the Linux VM Lab ..................................................... 492
Uploading and Downloading Files to the GNS3 IOS Router from Linux VMs
(File Transfer Testing Lab) ............................................................................................ 503
Copying (Cloning) a GNS3 Project ................................................................................ 511
Summary ...................................................................................................................... 514
■■Chapter 12: Building a Python Automation Lab Environment ........................... 515
Cisco CML-PERSONAL Software License Information and Software Downloads ......... 516
Downloading the Cisco CML-PERSONAL IOSvL2 (Switch) Image ................................. 516
Downloading the Cisco CML-PERSONAL IOSv (Router) Image and
startup_config Files ..................................................................................................... 517
Installing the Cisco CML-PERSONAL L2 Switch and CML-PERSONAL L3 on GNS3 ...... 518
Installing the Cisco CML-PERSONAL L2 Switch on GNS3 ............................................. 518
Quick Communication Test on CML L2 Switch Integration on GNS3 .................................................. 528
Installing the Cisco CML-PERSONAL L3 Router on GNS3 ............................................. 529
Quick Communication Test on CML L3 Router Integration on GNS3 ................................................... 539
Building a CML-PERSONAL Lab Topology ..................................................................... 541
Summary ...................................................................................................................... 548
■■Chapter 13: Python Network Automation Lab: Basic Telnet .............................. 549
Python Network Automation: Telnet Labs ..................................................................... 549
Telnet Lab 1: Interactive Telnet Session to Cisco Devices on a Python Interpreter ...... 551
Telnet Lab 2: Configure a Single Switch with a Python Telnet Template ...................... 557
Telnet Lab 3: Configure Random VLANs Using a for Loop ............................................ 562
Telnet Lab 4: Configure Random VLANs Using a while Loop ........................................ 566
Telnet Lab 5: Configure 100 VLANs Using the for ~ in range Loop Method .................. 569
Telnet Lab 6: Add a Privilege 3 User on Multiple Devices Using IP Addresses
from an External File .................................................................................................... 573
Telnet Lab 7: Taking Backups of running-config (or startup-config) to
Local Server Storage .................................................................................................... 579
Summary ...................................................................................................................... 582
■■Chapter 14: Python Network Automation Labs: SSH paramiko and netmiko .... 583
Python Network Automation Labs Using the paramiko and netmiko Libraries ............ 583
Python SSH Labs: paramiko ......................................................................................... 584
paramiko Lab 1: Configure the Clock and Time Zone of All Devices Interactively
in the Python Interpreter .............................................................................................. 584
paramiko Lab 2: Configuring an NTP Server on Cisco Devices Without
User Interaction (NTP Lab) ............................................................................................ 592
paramiko Lab 3: Create an Interactive paramiko SSH Script to Save Running
Configurations to the TFTP Server ................................................................................ 598
Python SSH Labs: netmiko ........................................................................................... 605
netmiko Lab 1: netmiko Uses a Dictionary for Device Information,
Not a JSON Object ........................................................................................................ 606
netmiko Lab 2: Develop a Simple Port Scanner Using a Socket Module and Then
Develop a nemiko Disable Telnet Script ....................................................................... 614
netmiko Lab 3: config compare .................................................................................... 621
Summary ...................................................................................................................... 628
■■Chapter 15: Python Network Automation Labs: cron and SNMPv3 ................... 629
Cron and SNMPv3 Labs ................................................................................................ 629
Cloning a GNS3 Project for the Next Lab ...................................................................... 630
Quick-Start to the Linux Scheduler, cron ...................................................................... 637
Ubuntu 20.04 LTS Task Scheduler: crontab ........................................................................................ 637
CentOS8.1 Task Scheduler: crond .......................................................................................................641
Learn cron Job Definitions with Examples .........................................................................................646
Using Python to Run an SNMPv3 Query ....................................................................... 648
Quick-Start Guide to SNMP ................................................................................................................ 649
Learn to Use SNMPwalk on a Linux Server ........................................................................................ 653
Borrowing Some Example Python SNMP Code ................................................................................... 666
Summary ...................................................................................................................... 673
■■Chapter 16: Python Network Automation Labs: Ansible, pyATS, Docker,
and the Twilio API ................................................................................................. 675
Python Network Automation Development Labs .......................................................... 675
Quick-Start Guide to Ansible: virtualenv Lab 1 ............................................................. 676
Installing virtualenv and Getting Started with Ansible ........................................................................ 678
Quick-Start Guide to pyATS (Genie): VirtualEnv Lab 2 .................................................. 685
Sendmail Lab Using an Imported Docker Image .......................................................... 700
Docker Components and Account Registration .................................................................................. 701
Docker Installation ..............................................................................................................................702
Test-Driving Docker ............................................................................................................................703
Docker Sendmail Python Lab ..............................................................................................................707
Lab: Sendmail Email Notification script Development ........................................................................ 712
CPU Utilization Monitoring Lab: Send an SMS Message Using Twilio .......................... 717
TWILIO Account Creation, Install Twilio Python Module and SMS Message Setup ............................. 718
CPU Utilization Monitoring Lab with an SMS Message ....................................................................... 723
Summary ...................................................................................................................... 732
■■Chapter 17: Upgrading Multiple Cisco IOS XE Routers ...................................... 733
Practical Python Network Automation Lab: IOS XE Upgrade Lab ................................. 733
Applying OOP Concepts to Your Network ..................................................................... 734
Flow Control and Controlling User Input: UID, PWD, and Information Collector ............ 738
Lab Preparation ............................................................................................................ 743
CSR 1000v IOS XE Software and Download ........................................................................................ 744
Cisco CSR 1000v Installation on VMware Workstation ....................................................................... 745
Discussion of How an IOS (IOS-XE/XR) Is Upgraded on Cisco Devices ......................... 756
Tasks Involved in a Cisco IOS Upgrade ...............................................................................................756
Summary ...................................................................................................................... 759
■■Chapter 18: Python Network Automation Lab: Cisco IOS Upgrade
Mini Tools Development ........................................................................................ 761
Cisco IOS Upgrade Application Development ............................................................... 761
Part A: Pre-check Tools Development Connectivity Validation Tool .............................. 762
Collect User’s Login Credentials and User Input .......................................................... 774
Collect a New IOS Filename and MD5 Value from a CSV File ....................................... 778
Check the MD5 Value of the New IOS on the Server .................................................... 788
Check the Flash Size on Cisco Routers ........................................................................ 792
Make Backups of running-config, the Interface Status, and the Routing Table ........... 796
Part B: IOS Uploading and More Pre-check Tools Development ................................... 799
IOS Uploading Tool ........................................................................................................ 799
Check the New IOS MD5 Value on the Cisco Device’s Flash ........................................ 804
Options to Stop or Reload the Routers ......................................................................... 810
Check the Reloading Device and Perform a Post-Reload Configuration Verification ... 819
Summary ...................................................................................................................... 829
■■Chapter 19: Python Network Automation Labs: Combining and
Completing the Cisco IOS Upgrade Application .................................................... 831
Creating a Single Python File ....................................................................................... 832
Summary ...................................................................................................................... 852
Final Words ................................................................................................................... 853
Index ..................................................................................................................... 855

 Learn and implement network automation within the Enterprise network using Python 3. This introductory book will be your guide to building an integrated virtual networking lab to begin your Network Automation journey and master the basics of Python Network Automation.

 The book features a review of the practical Python network automation scripting skills and tips learned from the production network, so you can safely test and practice in a lab environment first, various Python modules such as paramiko and netmiko, pandas, re, and much more. You'll also develop essential skills such as Python scripting, regular expressions, Linux and Windows administration, VMware virtualization, and Cisco networking from the comfort of your laptop/PC with no actual networking hardware. Finally, you will learn to write a fully automated and working Cisco IOS XE upgrade application using Python.

 Introduction to Python Network Automation uses a canonical order, where you beginat the bottom and by the time you have completed this book, you will at least reach the intermediate level of Python coding for enterprise networking automation using native Python tools.

What You'll Learn

• Build a proper GNS3-based networking lab for Python network automation needs

• Write the basics of Python code in both the Windows and Linux environments

• Control network devices using telnet, SSH, and SNMP protocols using Python codes

• Understand virtualization and how to use VMware workstation

• Examine virtualization and how to use VMware Workstation Pro

• Develop a working Cisco IOS upgrade application

Who This Book Is For

 IT engineers and developers, network managers and students, who would like to learn network automation using Python.