Cisco Certified DevNet Associate DEVASC 200-901 Official Cert Guide

Chris Jackson, CCIE No. 6256 (R&S and SEC), is a Distinguished Architect and CTO for Global Sales Training at Cisco. Chris is focused on digital transformation and showing customers how to leverage the tremendous business value Cisco technologies can provide. He is the author of Network Security Auditing (Cisco Press, 2010), CCNA Cloud CLDADM 210-455 Official Cert Guide (Cisco Press, 2016), and various online video courses for Cisco Press. He holds dual CCIEs in security and routing and switching, CISA, CISSP, ITIL v3, seven SANS certifications, and a bachelor’s degree in business administration. Residing in Franklin, Tennessee, Chris enjoys tinkering with electronics, robotics, and anything else that can be programmed to do his bidding. In addition, he is a 3rd Degree Black Belt in Taekwondo, rabid Star Wars fan, and has a ridiculous collection of Lego. His wife Piper and three children Caleb, Sydney, and Savannah are the true joy of his life and proof that not everything has to plug into a wall outlet to be fun. Jason Gooley, CCIE No. 38759 (R&S and SP), is a very enthusiastic and spontaneous person who has more than 20 years of experience in the industry. Currently, Jason works as a Technical Evangelist for the Worldwide Enterprise Networking Sales team at Cisco Systems. Jason is very passionate about helping others in the industry succeed. In addition to being a Cisco Press author, Jason is a distinguished speaker at Cisco Live, contributes to the development of the Cisco CCIE and DevNet exams, provides training for Learning@Cisco, is an active CCIE mentor, is a committee member for the Cisco Continuing Education Program (CE), and is a program committee member of the Chicago Network Operators Group (CHI-NOG), www.chinog.org. Jason also hosts a show called “MetalDevOps.” Jason can be found at www.MetalDevOps.com, @MetalDevOps, and @Jason_Gooley on all social media platforms. Adrian Iliesiu, CCIE No. 43909 (R&S), is a network engineer at heart with more than 15 years of professional IT experience. Currently, Adrian works as a Technical Leader with the Cisco DevNet Co-Creations team. During his career, Adrian has worked in several roles, including team leader and network, systems, and QA engineer across multiple industries and international organizations. When not working on innovative projects with customers and partners, Adrian advocates the advantages of network programmability and automation with a focus on enterprise and data center infrastructure. He is an established blog author, distinguished speaker at Cisco Live, and a recipient of the coveted Cisco Pioneer award. Adrian also appeared on Cisco TechWiseTV, Cisco Champion podcasts, and DevNet webinars. He holds a bachelor’s degree in Electronics and Telecommunications from Technical University of Cluj-Napoca and a master’s degree in Telecommunication Networks from Politehnica University of Bucharest. Ashutosh Malegaonkar is a Cisco Distinguished Engineer, a senior technical contributor, and an industry thought leader. His experience spans across different technology domains: ISR Platforms, Voice, Video, Search, Video Analytics, and Cloud. Over two decades at Cisco, he has done two startups and has won several accolades, including the Pioneer awards. He has delivered several keynotes and talks at Cisco Connect and Cisco Live. He has also been a Tech Field Day Speaker. With more than 25 years of professional experience, he currently leads the DevNet Co-Creations team whose mission is to co-create, innovate, and inspire alongside our strategic customers, partners, and developers. Ashutosh inspires those around him to innovate, and he is continually developing creative new ways to use software and Cisco APIs to solve real problems for our customers. He has a deep understanding of the breadth of Cisco products and technologies and where they can best be applied to serve our customers. Ashutosh has 16 approved patents and two publications.

Introduction xxv

Chapter 1 Introduction to Cisco DevNet Associate Certification 2

Do I Know This Already? 2

Foundation Topics 3

Why Get Certified 3

Cisco Career Certification Overview 6

Cisco DevNet Certifications 11

Cisco Certified DevNet Associate Certification (DEVASC) 12

Cisco Certified DevNet Professional Certification 13

Cisco DevNet Overview 14

Discover 15

Technologies 15

Community 16

Support 17

Events 17

DevNet Automation Exchange 18

Summary 20

Chapter 2 Software Development and Design 22

“Do I Know This Already?” Quiz 22

Foundation Topics 25

Software Development Lifecycle 25

Waterfall 27

Lean 28

Agile 29

Common Design Patterns 30

Model-View-Controller (MVC) Pattern 30

Observer Pattern 31

Linux BASH 32

Getting to Know BASH 32

Directory Navigation 35

cd 35

pwd 35

ls 36

mkdir 36

File Management 36

mv 37

rm 37

touch 37

cat 37

Environment Variables 37

Software Version Control 38

Git 39

Understanding Git 40

Using Git 42

Cloning/Initiating Repositories 42

Adding and Removing Files 43

Committing Files 45

Pushing and Pulling Files 45

Working with Branches 47

Merging Branches 50

Handling Conflicts 52

Comparing Commits with diff 53

Conducting Code Review 55

Exam Preparation Tasks 55

Review All Key Topics 56

Define Key Terms 56

Chapter 3 Introduction to Python 58

“Do I Know This Already?” Quiz 58

Foundation Topics 60

Getting Started with Python 60

Understanding Python Syntax 63

Data Types and Variables 66

Variables 66

Data Types 67

Integers, Floating Point, and Complex Numbers 68

Booleans 70

Strings 70

Lists 72

Tuples 74

Dictionaries 75

Sets 76

Input and Output 77

Getting Input from the User 77

The Mighty print() Function 77

Flow Control with Conditionals and Loops 78

If Statements 79

For Loops 80

While Loops 82

Exam Preparation Tasks 83

Review All Key Topics 83

Define Key Terms 84

Additional Resources 84

Chapter 4 Python Functions, Classes, and Modules 86

“Do I Know This Already?” Quiz 86

Foundation Topics 88

Python Functions 88

Using Arguments and Parameters 89

Object-Oriented Programming and Python 91

Python Classes 92

Creating a Class 92

Methods 93

Inheritance 94

Working with Python Modules 96

Importing a Module 97

The Python Standard Library 99

Importing Your Own Modules 100

Useful Python Modules for Cisco Infrastructure 101

Exam Preparation Tasks 104

Review All Key Topics 104

Define Key Terms 105

Chapter 5 Working with Data in Python 106

“Do I Know This Already?” Quiz 106

Foundation Topics 108

File Input and Output 108

Parsing Data 110

Comma-Separated Values (CSV) 110

JavaScript Object Notation (JSON) 113

Extensible Markup Language (XML) 115

YAML Ain't Markup Language (YAML) 117

Error Handling in Python 119

Test-Driven Development 121

Unit Testing 122

Exam Preparation Tasks 126

Review All Key Topics 126

Define Key Terms 127

Additional Resources 127

Chapter 6 Application Programming Interfaces (APIs) 128

“Do I Know This Already?” Quiz 128

Foundation Topics 130

Application Programming Interfaces (APIs) 130

Northbound APIs 130

Southbound APIs 130

Synchronous Versus Asynchronous APIs 131

Representational State Transfer (REST) APIs 132

RESTful API Authentication 133

Basic Authentication 134

API Keys 134

Custom Tokens 135

Simple Object Access Protocol (SOAP) 136

Remote-Procedure Calls (RPCs) 140

Exam Preparation Tasks 142

Review All Key Topics 142

Define Key Terms 142

Chapter 7 RESTful API Requests and Responses 144

“Do I Know This Already?” Quiz 144

Foundation Topics 146

RESTful API Fundamentals 146

API Types 146

API Access Types 147

HTTP Basics 148

Uniform Resource Locator (URL) 149

Method 150

REST Methods and CRUD 150

Deep Dive into GET and POST 151

HTTP Headers 152

Request Headers 153

Response Headers 153

Response Codes 154

XML 155

JSON 156

YAML 157

Webhooks 158

Tools Used When Developing with Webhooks 158

Sequence Diagrams 159

REST Constraints 160

Client/Server 160

Stateless 161

Cache 161

Uniform Interface 161

Layered System 162

Code on Demand 162

REST API Versioning 162

Pagination 162

Rate Limiting and Monetization 163

Rate Limiting on the Client Side 164

REST Tools 164

Postman 165

curl 168

HTTPie 169

Python Requests 171

REST API Debugging Tools for Developing APIs 172

Exam Preparation Tasks 172

Review All Key Topics 172

Define Key Terms 173

Chapter 8 Cisco Enterprise Networking Management Platforms and APIs 174

“Do I Know This Already?” Quiz 174

Foundation Topics 176

What Is an SDK? 176

Cisco Meraki 178

Cisco DNA Center 189

Cisco SD-WAN 201

Exam Preparation Tasks 212

Review All Key Topics 212

Define Key Terms 212

Chapter 9 Cisco Data Center and Compute Management Platforms and

APIs 214

“Do I Know This Already?” Quiz 214

Foundation Topics 216

Cisco ACI 216

Building Blocks of Cisco ACI Fabric Policies 220

APIC REST API 223

UCS Manager 230

Cisco UCS Director 239

Cisco Intersight 246

Exam Preparation Tasks 252

Review All Key Topics 252

Define Key Terms 253

Chapter 10 Cisco Collaboration Platforms and APIs 254

“Do I Know This Already?” Quiz 255

Foundation Topics 257

Introduction to the Cisco Collaboration Portfolio 257

Unified Communications 257

Cisco Webex Teams 258

Cisco Unified Communications Manager (Unified CM) 259

Unified Contact Center 259

Cisco Webex 260

Cisco Collaboration Endpoints 260

API Options in the Cisco Collaboration Portfolio 261

Webex Teams API 261

API Authentication 262

Personal Access Tokens 262

Integrations 263

Bots 271

Guest Issuer 272

Webex Teams SDKs 273

Cisco Finesse 274

Cisco Finesse API 275

API Authentication 276

Finesse User APIs 277

Finesse Team APIs 279

Dialog APIs 279

Finesse Gadgets 281

Webex Meetings APIs 281

Authentication 283

Integration API Keys 283

Webex XML APIs 284

Creating a New Meeting 284

Listing All My Meetings Meeting 286

Setting or Modifying Meeting Attributes 287

Deleting a Meeting 288

Webex Devices 289

xAPI 290

xAPI Authentication 290

xAPI Session Authentication 291

Creating a Session 291

Getting the Current Device Status 291

Setting Device Attributes 292

Registering an Event Notification Webhook 293

Room Analytics People Presence Detector 294

Cisco Unified Communications Manager 294

Administrative XML 294

Cisco AXL Toolkit 295

Accessing the AXL SOAP API 296

Using the Zeep Client Library 296

Using the CiscoAXL SDK 297

Exam Preparation Tasks 298

Review All Key Topics 298

Define Key Terms 298

Chapter 11 Cisco Security Platforms and APIs 300

“Do I Know This Already?” Quiz 301

Foundation Topics 302

Cisco's Security Portfolio 302

Potential Threats and Vulnerabilities 303

Most Common Threats 303

Cisco Umbrella 304

Understanding Umbrella 304

Cisco Umbrella APIs 305

Authentication 306

Cisco Firepower 314

Firepower Management Center APIs 315

Cisco Advanced Malware Protection (AMP) 320

Listing All Computers 323

Listing All Vulnerabilities 323

Cisco Identity Services Engine (ISE) 326

ISE REST APIs 327

ERS API Authentication 328

Creating an Endpoint Group 329

Creating an Endpoint and Adding It to a Group 330

Other ISE APIs 331

Cisco Threat Grid 331

Threat Grid APIs 332

Threat Grid API Format 332

API Keys 333

Who Am I 333

The Data, Sample, and IOC APIs 334

Feeds 335

Exam Preparation Tasks 337

Review All Key Topics 337

Define Key Terms 338

Chapter 12 Model-Driven Programmability 340

“Do I Know This Already?” Quiz 340

Foundation Topics 342

NETCONF 343

YANG 347

RESTCONF 367

Model-Driven Telemetry 371

Exam Preparation Tasks 372

Review All Key Topics 372

Define Key Terms 372

Chapter 13 Deploying Applications 374

“Do I Know This Already?” Quiz 374

Foundation Topics 376

Application Deployment Models 376

NIST Definition 376

Essential Characteristics 377

Service Models 378

Application Deployment Options 379

Private Cloud 379

Public Cloud 379

Hybrid Cloud 380

Community Cloud 381

Edge and Fog Computing 381

Application Deployment Methods 382

Bare-Metal Application Deployment 382

Virtualized Applications 383

Cloud-Native Applications 384

Containerized Applications 384

Serverless 386

DevOps 388

What Is DevOps? 390

Putting DevOps into Practice: The Three Ways 391

First Way: Systems and Flow 391

Second Way: Feedback Loop 392

Third Way: Continuous Experimentation and Learning 393

DevOps Implementation 394

Docker 398

Understanding Docker 398

Namespaces 398

Cgroups 399

Union File System 399

Docker Architecture 400

Using Docker 401

Working with Containers 403

Dockerfiles 410

Docker Images 411

Docker Hub 414

Exam Preparation Tasks 419

Review All Key Topics 419

Define Key Terms 419

Additional Resources 419

Chapter 14 Application Security 420

“Do I Know This Already?” Quiz 420

Foundation Topics 422

Identifying Potential Risks 422

Common Threats and Mitigations 423

Open Web Application Security Project 424

Using Nmap for Vulnerability Scanning 426

Basic Nmap Scan Against an IP Address or a Host 427

CVE Detection Using Nmap 427

Protecting Applications 429

Tiers of Securing and Protecting 430

Encryption Fundamentals 431

Public Key Encryption 431

Data Integrity (One-Way Hash) 432

Digital Signatures 432

Data Security 433

Secure Development Methods 434

Securing Network Devices 437

Firewalls 437

Intrusion Detection Systems (IDSs) 439

Intrusion Prevention Systems (IPSs) 440

Domain Name System (DNS) 440

Load Balancing 443

Exam Preparation Tasks 446

Review All Key Topics 446

Define Key Terms 447

Chapter 15 Infrastructure Automation 448

“Do I Know This Already?” Quiz 449

Foundation Topics 451

Controller Versus Device-Level Management 451

Infrastructure as Code 454

Continuous Integration/Continuous Delivery Pipelines 455

Automation Tools 458

Ansible 458

Puppet 462

Chef 465

Cisco Network Services Orchestrator (NSO) 467

Cisco Modeling Labs/Cisco Virtual Internet Routing Laboratory (CML/VIRL) 474

Python Automated Test System (pyATS) 476

Exam Preparation Tasks 479

Review All Key Topics 479

Define Key Terms 480

Chapter 16 Network Fundamentals 482

“Do I Know This Already?” Quiz 482

Foundation Topics 484

Network Reference Models 484

The OSI Model 484

The TCP/IP Model 488

Switching Concepts 492

Ethernet 492

MAC Addresses 493

Virtual Local-Area Networks (VLANs) 494

Switching 495

Routing Concepts 496

IPv4 Addresses 496

IPv6 Addresses 501

Routing 504

Exam Preparation Tasks 507

Review All Key Topics 507

Define Key Terms 508

Chapter 17 Networking Components 510

“Do I Know This Already?” Quiz 510

Foundation Topics 512

What Are Networks? 512

Elements of Networks 516

Hubs 517

Bridges 517

Switches 518

Virtual Local Area Networks (VLANs) 520

Routers 521

Routing in Software 522

Functions of a Router 524

Network Diagrams: Bringing It All Together 526

Software-Defined Networking 526

SDN Controllers 529

Cisco Software-Defined Networking (SDN)