Java Microservices and Containers in the Cloud: With Spring Boot, Kafka, PostgreSQL, Kubernetes, Helm, Terraform and AWS EKS

Table of Contents....5

About the Author....21

About the Technical Reviewer....22

Acknowledgments....23

Introduction....24

Chapter 1: Microservices for the Enterprise....26

Computing Architecture Paradigms....27

Centralized Computing....27

Distributed Computing....29

Decentralized Computing....32

Eventually Consistent Software Systems....34

Atomic Consistency....34

Eventual Consistency....36

Eventually Consistent, Decentralized Systems....38

Service Granularity....40

Monolith....40

Macroservice....41

Mini Service....41

Microservices....42

The Hexagonal Architecture Metaphor....43

Layered Architecture....44

The Ports and Adapter Architecture....44

Hexagonal Architecture....47

Microservice Metamodel....47

Your First Java Microservice....50

Spring Boot....51

Design Your First Hexagonal Microservice....51

Code Organization....53

Understanding the Code....55

Build and Run the Code....60

Test the Microservice Using UI....63

Test the Microservice Using cURL....68

Summary....68

Chapter 2: More Hands-on Microservices....69

Microservices Using MongoDB and RestTemplate....70

Design the Microservices....70

Code Organization....71

Understanding the Code....74

Build and Run the Microservice....81

Testing the Microservices....84

Microservices Using Spring Cloud....85

Design the Microservices....85

Understanding the Code....86

Build and Run the Microservice....89

Testing the Microservices....91

HATEOAS and HAL....91

HATEOAS Explained....92

HAL Explained....93

Microservices Using HATEAOS and HAL....94

Design the Microservices....94

Code Organization....95

Understanding the Code....96

Build and Run the Microservice....99

Testing the Microservice....101

Summary....102

Chapter 3: Onion and Hexagonal Architecture in Practice....104

Microservices Using PostgreSQL and RestTemplate....105

Design the Microservice....105

Understanding the Code....106

Build and Run the Microservice....115

Testing the Microservice....118

Microservices Using MongoDB and CrudRepository....119

Hexagonal Architecture Revisited....120

Understanding the Code....120

Build and Run the Microservice....123

Testing the Microservices....125

The Onion Architecture....127

Onion Architecture Design....127

Onion vs. Hexagonal Architecture....129

GraphQL....130

GraphQL Explained....130

Onion Architecture Microservice Example....131

Onion Design for the Microservice....132

Code Organization....133

Understanding the Code....134

Build and Run the Microservice....146

Testing the Microservice....148

Summary....155

Chapter 4: Message Oriented Microservices....156

Characteristics of Microservices....157

Microservices Are Autonomous....157

Microservices Are Evolutionary....158

The Honeycomb Analogy....160

Async, Still Request-Reply....160

Async Request....160

Async Request-Reply....161

Sync Over Async Microservices....163

Design Microservices Over Async Channel....163

Understanding the Code....164

Build and Run the Microservice....174

Testing the Microservice....176

SEDA and Microservices....177

SEDA Architecture....177

Microservices Architecture as a Network of Stages....179

Async HTTP on Sync over Async Microservices....180

Understanding the Code....180

Build and Run the Microservice....185

Testing the Microservice....188

Summary....191

Chapter 5: Microservices Integration in Practice....193

Microservices Scalability in the Cloud....194

Vertical Scalability....194

Horizontal Scalability....195

Microservices Scalability....195

Sync over Async Dynamics....197

Publisher Subscriber Combinations....198

Publisher Subscriber Instance Combinations....198

Microservices Sequential Processing....201

Design Sequential Processing Microservices....201

Understanding the Code....203

Build and Run the Microservice Sequential Processing....218

Testing Sequential Request Processing....224

Inspecting the Microservice Partition assignment....229

Microservices Parallel Processing....231

Design Parallel Processing Microservices....232

Parallelism and Thread Safety....233

Understanding the Code....234

Build and Run the Microservice Parallel Processing....236

Testing Parallel Request Processing....240

Summary....244

Chapter 6: Production Grade Message Oriented Microservices....245

Inter-Microservices Wire Level Options....246

XML-RPC and SOAP....246

REST and JSON-RPC....247

RPC vs. Messaging....248

RPC Style Messaging....248

HTTP Methods for CRUD on Resources....249

CRUD Microservices Over Kafka on MongoDB....251

Design CRUD Over Async Channel on MongoDB....252

Understanding the Source Code....253

Build and Run the Microservice....262

Testing the Microservices....268

CRUD Microservices Over Kafka on PostgreSQL....270

Design CRUD Over Async Channel on PostgreSQL....271

Understanding the Source Code....271

Build and Run the Microservice....272

Testing the Microservice....277

Aggregating Responses from Multiple Microservices....280

Aggregator Integration Pattern....280

Design the Microservice Aggregator....282

Understanding the Source Code....283

Build and Run the Microservice....289

Testing the Microservice....294

Summary....301

Chapter 7: Introducing Docker....302

Different Types of Virtualization....303

Traditional Deployment....303

Virtualization....304

Containers....306

Containers in Detail....306

History of Containers....306

Container Internals....307

Virtualization vs. Containerization....308

Docker Concepts....310

Layered Filesystems....310

Docker Images....310

Docker Images vs. Containers....314

Docker Registry....318

Hello World Tomcat in Docker....320

Run Tomcat Container....320

Build and Run Java App without Java....328

Using a Maven Container....329

Creating a Maven Archetype....329

Build and Package Using Maven Container....332

Deploy Webapp Using Maven Container....335

Build and Run Java App with Docker Compose....337

Using Docker Compose....338

Build the First Java Microservice with Docker....341

Dockerizing the Microservice Using Jib....341

Understanding the Source Code....342

Build and Push Images to Docker Hub....345

Docker Hub Registry and Repository....347

Pull Image and Run Container....349

Build a Microservice Using a Dockerfile....354

Dockerfiles....355

Understanding the Source Code....355

Build and Run the Microservice Using a Dockerfile....357

Summary....364

Chapter 8: Microservice Containers....365

Container Networking....366

Links....366

Networks....367

Container Logs....368

Console Output Logging....368

Microservice and MongoDB Containers Using Links....370

Designing the Container Topology....370

Understanding the Source Code....373

Run Containers Using Dockerfiles....373

Testing the Microservice Containers....378

Microservice and MongoDB Containers Using a Network....380

Designing the Container Topology....381

Understanding the Source Code....381

Run Containers Using Dockerfiles....381

Testing the Microservice Containers....387

Microservice Container with PostgreSQL in Host....389

Designing the Container Topology....389

Understanding the Source Code....391

Container to PostgreSQL in Host Configuration....391

Run Containers Using Dockerfiles....392

Testing the Microservice Containers....396

Microservice and PostgreSQL in Container....401

Designing the Container Topology....402

Understanding the Source Code....403

Run Containers Using Dockerfiles....403

Testing the Microservice Containers....408

Container Storage....413

Volumes....414

Microservice and MongoDB Containers Using File Mount....414

Designing the Container Topology....415

Understanding the Source Code....416

Run Containers Using Dockerfiles....417

Testing the Microservice Containers....421

Summary....424

Chapter 9: Composing Multi-Service Containers....425

Introducing Docker Compose....426

Docker Compose YAML....427

Docker Compose Use Cases....428

Composing Microservice with PostgreSQL Containers....429

Composing the Container Topology....430

Understanding the Source Code....431

Run Containers Using Docker Compose....436

Testing the Microservice Containers....441

Composing Microservice with MongoDB Containers....444

Composing the Container Topology....444

Understanding the Source Code....445

Run Containers Using Docker Compose....447

Testing the Microservice Containers....450

Composing Microservice with PostgreSQL and Kafka....452

Composing the Container Topology....452

Understanding the Source Code....453

Run Containers Using Docker Compose....459

Testing the Microservice Containers....464

Composing Microservices with MongoDB and Kafka....467

Composing the Container Topology....467

Understanding the Source Code....468

Run Containers Using Docker Compose....469

Testing the Microservice Containers....472

Summary....474

Chapter 10: Microservices with Kubernetes....475

The World of Kubernetes....476

Kubernetes Architecture....477

The Control Plane....478

The Node....479

Kubernetes Deployment....479

Containers....480

Pods....480

ReplicaSets....481

Deployment....481

Accessing Kubernetes Services....482

Accessing Kubernetes Deployments....482

Kubernetes Service....483

Traffic Routing to Kubernetes....486

Cluster IP....486

NodePorts....487

Load Balancer....489

Ingress....490

State Management....492

Scale Out vs. State Management....492

StatefulSets....493

Persistent Volume Claim....495

Persistent Volume....495

Kubernetes Clusters....496

Minikube....496

Microservices and MongoDB in Kubernetes....496

Design Microservices Deployment Topology....497

Understanding the Source Code....498

Run Microservices in Kubernetes....509

Testing the Microservice Pods....519

Accessing Kubernetes Deployments....520

Microservices and PostgreSQL in Kubernetes....527

Design Microservices Deployment Topology....527

Understanding the Source Code....528

Run Microservices in Kubernetes....534

Testing the Microservice Pods....536

Resiliency of Kubernetes Pods....539

State Retention....539

Summary....543

Chapter 11: Message Oriented Microservices in Kubernetes....544

Microservices Over Kafka with PostgreSQL in k8s....545

Design the Microservices Orchestration Topology....545

Understanding the Source Code....546

Run Microservices in Kubernetes....553

Testing the Microservice Pods....556

Load Testing the Microservice Pods....560

Microservices Over Kafka with MongoDB in k8s....563

Design the Microservices Orchestration Topology....563

Understanding the Source Code....564

Run Microservices in Kubernetes....566

Testing the Microservice Pods....568

Load Testing the Microservice Pods....568

Connect to the MongoDB Pod Using kubectl....569

Ingress Routing of Microservices....572

Design Ingress Routing Topology....573

Environment Configurations....573

Understanding the Source Code....575

Run Ingress and Microservices in Kubernetes....580

Describing Ingress....582

Testing the Microservice Pods....583

Summary....588

Chapter 12: Automating Kubernetes Deployment and Helm....589

Introducing a Simple Java Microservice....590

Designing Your Simple Microservices....590

Code Organization....591

Understanding the Source Code....592

Build and Run the Microservice....593

Testing the Microservice....595

Automating the Docker Build....595

Understanding the Source Code....595

Build and Run the Microservice....597

Testing the Microservice....603

Automating Docker Push....604

Understanding the Source Code....604

Build and Run the Microservice....606

Testing the Microservice....609

Automating Kubernetes Deployment....609

Code Organization....609

Build and Run the Microservice....611

Testing the Microservice....612

Helm....612

What Is Helm?....613

Helm Nomenclature....613

Client-Server Helm Architecture....614

How Helm Works....615

Helm Package Microservice....617

Code Organization....617

Creating Your First Helm Chart....618

Confirming Helm Chart Accuracy....621

Build and Run the Microservice....623

Testing the Microservice....626

Helm Release Upgrades....627

Helm Release Rollback....630

Helm-Packaging Multi-Microservices....632

Designing Helm-Based Deployment Topology....633

Code Organization....633

Understanding the Source Code....637

Helm Chart for PostgreSQL....637

Common Chart for Microservices and Adminer....642

Helm Chart for Ingress....643

Build and Run the Microservice....645

Testing the Microservice....647

Helmfile Packaging Multi-Microservices....649

Code Organization....650

Understanding the Source Code....652

Build and Run the Microservice....655

Testing the Microservice....658

Summary....659

Chapter 13: CI/CD for Microservice Containers....660

CI and CD....661

DevOps....661

Continuous Integration (CI)....662

Continuous Delivery (CD)....663

Continuous Deployment (CD)....663

Google Skaffold....663

Skaffold Workflow....664

CI and CD Example for Microservices....665

Code Organization....665

Understanding the Source Code....666

Build and Run the Microservice....670

Testing the Microservices....672

Summary....676

Chapter 14: Microservices in AWS Elastic Compute Cloud....678

Cloud Computing....679

Public Clouds....679

Cloud Deployment Models....681

Public Cloud....681

Private Cloud....682

Hybrid Cloud....682

Multi-Cloud....682

Distributed Computing....682

Amazon Web Services (AWS)....684

VPC....685

Subnet....685

Public Proxy Subnet....686

NAT Gateway....686

EC2....687

Route Tables....687

Internet Gateway....687

Infrastructure as Code (IaC)....688

Terraform....689

Setting Up AWS EC2 Using Terraform....690

Design a Mini Data Center in the Cloud....690

Code Organization....691

Understanding the Source Code....692

Build and Spin EC2 Server in the Cloud....700

Accessing Your EC2 in AWS Cloud Using SSH....703

Installing JRE in AWS EC2....704

Deploying Microservice in AWS EC2....705

Copy the Microservice Executable to the Cloud....706

Run the Microservice....706

Test the Microservice Using UI....708

Summary....709

Chapter 15: Microservices in AWS Elastic Kubernetes Service....710

The Amazon Elastic Kubernetes Service....711

EKS Control Plane....711

EKS Worker Nodes....711

Setting Up AWS EKS Using Terraform....712

Designing an EKS Topology in an AWS Cloud....712

Code Organization....714

Understanding the Source Code....714

Setups Required to Operate an EKS Cluster....725

Build and Spin Your EKS Cluster in AWS....725

Deploying Containers in AWS EKS....727

Testing the Microservice in EKS....730

Summary....732

Appendix A: Using cURL and Postman....734

cURL Operations for HTTP....735

Using HTTP GET to Retrieve an Entity....735

Using HTTP POST to Create an Entity....736

Using HTTP PUT to Replace an Entity....737

Using HTTP PATCH to Modify an Entity....738

Using HTTP DELETE to Delete an Entity....740

Postman for HTTP Operations....740

Using HTTP GET to Retrieve an Entity with Postman....740

Using HTTP POST to Create an Entity with Postman....741

Summary....743

Appendix B: Using MongoDB....744

Install MongoDB on the macOS....744

Downloading and Extracting the MongoDB Tarball....744

Installing the Tarball....746

Running the MongoDB Server....747

Opening the MongoDB Terminal....749

Install MongoDB on Windows....750

Downloading and Extracting the MongoDB Archive....750

Installing the ZIP Archive....751

Running the MongoDB Server....751

Opening the MongoDB Terminal....752

Run Commands Against the MongoDB Server....753

Creating a New Document....753

Reading a Document....754

Updating a Document....754

Deleting a Document....755

Dropping a Collection....755

Exiting the Mongo Terminal....756

Summary....756

Appendix C: Using PostgreSQL....757

Install PostgreSQL on macOS....757

Downloading and Extracting the Image....757

Installing the Image....759

Starting and Stopping PostgreSQL Server....771

Interacting Using psql Terminal....772

Opening the PostgreSQL Server for Remote Clients....772

Opening PostgreSQL on the Host Machine for Docker Clients....773

Install PostgreSQL in Windows OS....774

Downloading and Extracting the ZIP Archive....774

Installing the ZIP Archive....775

Starting and Stopping PostgreSQL Server....777

Interacting Using the psql Terminal....778

Create a Database Using pgAdmin....779

Logging In to PostgreSQL Server....779

Run Command Against PostgreSQL Using psql....784

Creating a New Table....786

Listing Existing Tables....786

Describing the Structure of an Existing Table....787

Inserting a Row into a Table....788

Reading Data from the Table....788

Updating a Table....789

Deleting Rows from a Table....789

Dropping a Table....790

Exiting the psql Terminal....790

Summary....791

Appendix D: Using Kafka....792

Installing Kafka....792

Downloading and Extracting the Image....792

Starting and Stopping Kafka Broker....794

Run Commands Against Kafka Broker....795

Creating a Topic....795

Viewing a Topic....796

Reading Events from a Topic....796

Publishing Events to a Topic....797

Deleting a Topic....798

Summary....798

Appendix E: Container Tools....799

Docker Env for Intel based Mac....799

Uninstalling the Existing Docker Desktop....800

Installing HyperKit....800

Installing Docker CLI....802

Container Orchestration....804

Installing kubectl....805

Installing Minikube....806

Configuring Minikube....808

Starting Minikube....809

Starting Docker env in the Terminal....811

Accessing Docker from the Terminal....811

Installing Docker Compose....812

Stopping Minikube....814

Deleting Minikube....814

Troubleshooting Minikube....815

Expose Minikube Services....817

Enabling the Ingress Addon....817

Enabling the Ingress DNS Addon....819

Manage Kubernetes Applications....819

Deploying Kubernetes Applications....819

Inspecting the Kubernetes Deployment....820

Accessing the Kubernetes Application....821

Docker Env for Apple Silicon-Based Mac....822

Installing Podman....822

Creating and Starting a VM....822

Starting Minikube....824

Installing Helm on the Mac....826

Summary....826

Appendix F: Cloud Tools....827

AWS CLI....827

Downloading AWS CLI....828

Installing AWS CLI....828

Configuring AWS CLI....829

AWS IAM....829

Downloading AWS IAM....829

Configuring AWS IAM....830

kubectl for EKS....832

Joining Worker Nodes to EKS....833

Terraform....834

Installing Terraform....835

Upgrading Terraform....835

Verifying Terraform....836

Summary....836

Index....837

Spring Boot helps developers create applications that simply run. When minimal configuration is required to start up an application, even novice Java developers are ready to start. But this simplicity shouldn't constrain developers in addressing more complex enterprise requirements where microservice architecture is concerned. With the need to rapidly deploy, patch, or scale applications, containers provide solutions which can accelerate development, testing as well as production cycles. The cloud helps companies to scale and adapt at speed, accelerate innovation and drive business agility, without heavy upfront IT investment. What if we can equip even a novice developer with all that is required to help enterprises achieve all of this, this book does this and more. Java Microservices and Containers in the Cloudoffers a comprehensive guide to both architecture and programming aspects to Java microservices development, providing a fully hands-on experience. We not only describe various architecture patterns but also provide practical implementations of each pattern through code examples. Despite the focus on architecture, this book is designed to be accessible to novice developers with only basic programming skills, such as writing a "Hello World" program and using Maven to compile and run Java code. It ensures that even such readers can easily comprehend, deploy, and execute the code samples provided in the book. Regardless of your current knowledge or lack thereof in Docker, Kubernetes, and Cloud technologies, this book will empower you to develop programming skills in these areas. There is no restriction on beginners attempting to understand serious and non-trivial architecture constraints. While mastering concurrency and scalability techniques often requires years of experience, this book promises to empower you to write microservices, as well as how to containerize and deploy them in the cloud. If you are a non-programming manager who is not afraid to read code snippets, this book will empower you to navigate the challenges posed by seasoned architects. It will equip you with the necessary understanding of specialized jargon, enabling you to engage in more meaningful discussions and break through barriers when collaborating with programmers, architects and engineers across the table.

The code examples provided in the book are intentionally designed to be simple and accessible to all, regardless of your programming background. Even if you are a C# or Python programmer and not familiar with Java, you will find the code examples easy to follow and understand.

You will

• Acquire proficiency in both RPC-style and Messaging-style inter-microservice communication
• Construct microservices utilizing a combination of SQL (PostgreSQL) and NoSQL (MongoDB) databases
• Leverage Liquibase, a database schema version control tool, and administer UI in conjunction with PostgreSQL
• Leverage both GraphQL and conventional REST approaches side by side
• Gain practical experience in implementing Hexagonal and Onion Architectures through hands-on exercises
• Integrate asynchronous processing into your Java applications using powerful APIs such as DeferredResult and CompletableFuture

Who it's for:

Developers, programmers and Architects who want to level up their Java Micoservices and Archtecture knowledge as well as managers who want to brush up on their technical knowledge around the topic.