# Project Context: PetCLinic  Microservices -> AWS

## Context and Scope

This project will migrate the Spring PetClinic Microservices demo from its local/on-premise setup to AWS Cloud. The focus is infrastructure modernization, CI/CD automation, observability, and resilience but not application feature development.

### Stakeholders

| Role | Responsibility | 
|----|----|
| Project Sponsor | Funding, final approval | 
| Project Manager | Scheduling, stakeholder coordination |
| Cloud Architect | Architecture, service selection |
| Dev Lead | App changes for cloud readiness |
| DevOps Engineer | CI/CD, IaC, deployments, monitoring |
| Security Team | IAM, encryption |
| End Users / Demo Audience | Acceptance and usability feedback

### Expectations

- No app feature development unless necessary for cloud deployment.
- AWS is the only target cloud

### Objectives

- Run full PetClinic microservices on AWS with CI/CD.
- Observability: logs, metrics, traces for 100% of services.
- Cost target: keep monthly infra cost under a defined limit (set by Project Sponsor).
- Security: secrets encrypted, least-privilege IAM, HTTPS for all endpoints.

### Deadlines

| Milestone | Date |
|----|----|
| Project approval | Oct 27, 2025 |
| CI/CD & Automation | Nov 3, 2025 |
| Infrastructure | Nov 10,  2025 |
| Data | Nov 17, 2025 |
| Observability | Nov 24, 2025 |
| Prep: Presentation, Demo, and Pre-defense | Dec 3, 2025 |

## In Scope

| Included items | Objective |
|----|----|
| Application | Only necessary changes (if applicable) to facilitate cloud integration |
| Infrastructure | Design and deploy a reproducible, cloud-native architecture |
| CI/CD Automation | Implement automated build, test, and deployment pipelines |
| Containerization | Adapt existing microservices to use AWS.|
| Monitoring & Logging | Centralized logs, metrics, and traces |
| Security & IAM | Least-privilege IAM roles, encryption, and subnet segmentation. |
| Backup & Recovery | Redundancy, failover, backup, BCP/DRP |
| Documentation | Architecture diagrams, specifications, and operational runbooks. |

## Out of Scope

| Excluded items | Reason |
|----|----|
| Application feature or UI changes | Funcitoniality remains unchanged. |
| Multi-cloud or hybrid deployment | Focus solely on AWS environment. |
| Cost-optimization | Addressed in a later project if necessary |


## Requirements

### Functional requirements
| Stakeholder / Role | Requirement | Description |
|----|----|----|
| **Developers** | Continuous Integration | Each merge must trigger automated build, test, and image creation. |
| | Local to Cloud Parity | Development environment must mirror AWS setup. |
| **DevOps Engineers** | Automated Deployment | CI/CD pipeline must deploy microservices to Dev, Staging, and Prod environments automatically. |
| | Test Automation | Integration tests must run automatically in CI/CD pipeline. |
|| Infrastructure as Code | All AWS resources defined through configuration files |
| | Monitoring & Alerts | Centralized logging, metrics, and tracing for all microservices. Automated alerting for service downtime or threshold breaches. |
| | Scalability | Services must be scalable |
| **Security Team** | Access Control | Roles per service with least-privilege permissions.|
| | Secrets Management | All secrets stored securely. |
| **Product / Management** | Availability & Demo Readiness | System must be reliable and presentable for client or internal demos.|
| **End Users (Demo Audience)** | Stable Access | Web UI and APIs must remain responsive under typical load. |

### Non-Functional Requirements
| Category | Requirement | Standard |
|----|----|----|
| **Development** | Local to Cloud parity | Docker Compose or local ECS simulation |
| **Maintainability** | IaC  | Code stored in version control |
| **Performance** | Pipeline execution time | < 10 minutes per merge |
| | Scaling | Services can be scaled horizontally |
| | API / UI response | p95 latency < 200 ms under normal demo load |
| **Reliability** | Deployment success rate | ≥ 99% successful deployments |
| | Alert response | Alerts trigger within < 5 minutes of failure detection |
| | Error tolerance | < 0.1% failed requests |
| **Availability** | System uptime | ≥ 99.9% uptime |
| **Observability** | Logs, Metrics, Traces | Centralized in monitoring solution |
| **Security** | Least-privileged Roles | Roles restricted per service; no default full-access policies |
| | Secret encryption | Secrets stored in AWS |
| **Continuity** | RPO / RTO | RPO ≤ 5 min, RTO ≤ 30 min using RDS Multi-AZ and S3 backups |
| **Cost** | Budget target | Monthly AWS cost ≤ defined cap |

## System Components — Spring PetClinic Microservices
| Component | Role / Function | Dependencies | Notes |
|----|----|----|----|
| `spring-petclinic-admin-server` | Provides admin UI and dashboards | Microservices, Config Server | Central monitoring and management interface |
| `spring-petclinic-api-gateway` | Routes external requests to microservices | Customers, Vets, Visits, GenAI services | Single entry point for all APIs; can handle load balancing |
| `spring-petclinic-config-server` | Centralized configuration | Git repo | Supplies configuration to all microservices at runtime |
| `spring-petclinic-customers-service` | Manages customer data | RDBMS, Config Server | Core domain service |
| `spring-petclinic-vets-service` | Manages veterinary staff | RDBMS, Config Server | Lookup and assignment of vets |
| `spring-petclinic-visits-service` | Manages pet visit records | RDBMS, Customers Service | Tracks appointments and visit history |
| `spring-petclinic-genai-service` | Optional AI / generative service | Microservices, RDBMS | Provides a chatbot interface to the application. |
| `spring-petclinic-discovery-server` | Service registry / discovery | All microservices | Enables service-to-service discovery |
| RDBMS | Persistent storage | Customers, Vets, Visits | Single relational database supporting multiple services |

## Architecture and Specifications

### Project
- Kanban as agile methodology
- Breakdown of work and phases:
	- Infrastructure Setup
	- Service Orchestration
	- Configuration Management
	- CI/CD Automation
	- Security
	- Resilience
	- Observability
#### Assignments:

| Role | Responsibilities |
|----|----|
| **Cloud Architect** | Design AWS target architecture, network, and IAM structure |
| **DevOps Engineer** | Build CI/CD pipelines, container orchestration, monitoring setup  |
| **Dev Lead** | Containerize services, modify configs for cloud compatibility     |
| **Database Engineer** | Migrate data from local RDBMS to AWS RDS, manage schema updates |
| **Security Team** | Set up access and roles for services |
| **Everyone** | Validate deployments, pipeline runs, rollback testing |
| **Project Lead** | Manage Asana Kanban board, ensure alignment and progress tracking |

### Source Code

- Architecture Type: Microservices deployed via containers, managed by ECS, behind an AWS Application Load Balancer (ALB).
- Review via pull request process:
	- All commits merged via PRs.
	- Peer review required before merging.
- Vaildation: Run tests during pipeline build

## CI/CD

- Goal: Automate the entire software delivery process for all PetClinic microservices via Jenkins

### Development Cycle Stages

| Stage | Description |
|----|----|
| **01. Code & Merge** | Developer writes code and merges it with the staging branch |
| **02. Build** | Compile, resolve dependencies |
| **03. Unit Test** | Run service-level tests |
| **04. Containerize** | Build Docker image for service |
| **05. Security Scan** | Security validation via Trivy |
| **06. Push to Registry** | Push validated image |
| **07. Deploy to Staging** | Deploy for validation |
| **08. Integration tests** | Validate service communication|
| **09. Deploy to Production** | Promote validated build |
| **11. Observability Check** | Validate monitoring and alerts |

### Jobs and environments

- Each microservices has his own Jenkins pipeline

| Environment | Purpose | Infrastructure | Notes |
|----|----|----|----|
| **Development (Local)** | Local testing, feature validation | Docker Compose | Developer workstations |
| **Staging (AWS)** | Integration and pre-prod testing | ECS/EKS (staging cluster), RDS (test DB) | Mirrors production |
| **Production (AWS)** | Live system | ECS/EKS (prod cluster), RDS (prod DB) | Monitored|

 ## Storage

 ### 1. Database (RDBMS)

- Service: Amazon RDS (MySQL)
- IOPS: 3,000–6,000 (gp3 default) or provisioned as needed
- Volume: 20 GB per microservice schema
- Backup: Automated daily snapshots (14 day retention)

### 2. Block Storage

- Service: Amazon EBS (gp3)
- Use: EC2-hosted Jenkins, logs, or stateful containers
- IOPS: 3,000 baseline
- Backup: Not necessary

### 3. Object Storage

- Service: Amazon S3
- Use: Logs, backups, images
- Performance: Standard or Infrequent Access tiers
- Backup: Cross-region replication or versioning enabled

## Data

### 1. Location
- Eu-central-1 region
- Place database (RDS) and services in the same region and AZs for low latency.

### 2. Replication / Distribution
| Data Type | Replication / Distribution Strategy |
|----|----|
| **RDS (Postgres/MySQL)** | Multi-AZ synchronous replication |
| **S3 (images, artifacts)** | Automatic cross-AZ durability |

### 3. Links / Access

| Access type | Route|
|----|----|
| **Internal** | Microservices access RDS via private VPC links. |
| | Images in S3 accessed via IAM roles or pre-signed URLs. |
| **External** | ALB routes external requests. |
| | HTTPS enforced for secure data transfer. |

## Network

### Location

- Eu-central-1 region
- Deploy services across multiple AZs for high availability.
- All microservices, databases, and supporting infrastructure live inside a single VPC.
- Isolate the network from public internet by default

### Network Segmentation & Filtering
 - Public subnets: For ALB ,NAT gateway if needed.
 - Private subnets: For ECS/EKS tasks, RDS, Config Server, and internal microservices.
 - Security groups: Service-specific firewall rules
 - Tweak default ACLs if necessary

 ### Addressing

- VPC: `10.0.0.0/16`
- Public subnet: `10.0.1.0/24`
- Private subnet: `10.0.2.0/24`
- Every service/database gets a internal IP in the private subnet
- Only load balancer or NAT gateway have public IP

## Compute

### Nodes

| Environment | Nodes | Notes |
|----|----|----|
| **Staging** | 3 ECS container instances (EC2) | Handles staging microservices, mirrors production setup                                |
| **Production / Live** | 3 ECS container instances (EC2) | Fixed-size cluster, no autoscaling to reduce costs |
| **Scalability** | N/A for autoscaling | Fixed node count to reduce cost but still allow horizontal scaling via ECS task count or manual node addition. |

### Container Management

#### Container Registry:
- Amazon ECR for all microservice Docker images.
- Each microservice image tagged by Git commit SHA.

#### Microservice Packaging:

- Dockerized images for each service.
- Multi-stage Docker builds to reduce image size.

#### Deployment Strategy:

- ECS tasks run one or more containers per node.
- Service definitions ensure each microservice has the desired number of tasks.
- Jenkins updates ECS service definition after build.

### ECS Orchestration

#### Cluster Setup:
- One ECS cluster per environment (staging and production).
- EC2 launch type for fixed nodes.

#### Service Definitions:
- Each microservice has an ECS service with a desired task count.
- Service linked to ALB .