rbyapp-svc Kubernetes Implementation - A Case Study

📋 Table of Contents

Overview
Architecture
Quick Start
Documentation Structure
Prerequisites
Validation
Troubleshooting

Overview

This comprehensive Kubernetes implementation guide covers the deployment of a microservices architecture with:

1 Frontend (Svelte)
4 Microservices (2 Rust Rocket, 2 Spring Boot)
1 API Gateway (Nginx)
Supporting Infrastructure (PostgreSQL, Redis, ELK Stack, Prometheus, Grafana)

All components are deployed within the rbyapp-svc namespace with proper security, networking, and observability.

This repo created as part of my kubernetes learning & practice, for more comprehensive samples/references please refer to official documentations.

Architecture

High-Level System Design

┌─────────────────────────────────────────────────────────────┐
│                   Internet / Users                          │
└────────────────────────┬────────────────────────────────────┘
                         │
                    ┌────▼────┐
                    │ Ingress │ (TLS/SSL)
                    └────┬────┘
                         │
    ┌────────────────────▼────────────────────┐
    │    Nginx Gateway (rbyapp-gateway)       │
    │  • Rate Limiting                        │
    │  • DDoS Protection                      │
    │  • Request Routing                      │
    └────┬────┬────┬────┬──────────┬──────────┘
         │    │    │    │          │
    ┌────▼──┐ │    │    │          │
    │Frontend││    │    │          │
    │(Svelte)││    │    │          │
    └────────┘│    │    │          │
              │    │    │          │
    ┌─────────▼────▼────▼────┐     │
    │  Microservices         │     │
    │                        │     │
    │ ┌────────────────────┐ │     │
    │ │ Account (Rust)     │ │     │
    │ │ :8000              │ │     │
    │ └────────────────────┘ │     │
    │                        │     │
    │ ┌────────────────────┐ │     │
    │ │ Notification(Rust) │ │     │
    │ │ :8001              │ │     │
    │ └────────────────────┘ │     │
    │                        │     │
    │ ┌────────────────────┐ │     │
    │ │ Core (Spring Boot) │ │     │
    │ │ :8002              │ │     │
    │ └────────────────────┘ │     │
    │                        │     │
    │ ┌────────────────────┐ │     │
    │ │ Extra (SpringBoot) │ │     │
    │ │ :8003              │ │     │
    │ └────────────────────┘ │     │
    └────────┬───────────────┘     │
             │                     │
    ┌────────▼──────────────────────▼──────┐
    │   Data Layer                         │
    │                                      │
    │ ┌────────┐  ┌────────┐  ┌─────────┐  │
    │ │Postgres│  │ Redis  │  │ Backups │  │
    │ │Database│  │ Cache  │  │ Storage │  │
    │ └────────┘  └────────┘  └─────────┘  │
    └──────────────────────────────────────┘

    ┌──────────────────────────────────────┐
    │  Observability Stack                 │
    │                                      │
    │ ┌──────┐  ┌────────┐  ┌──────────┐   │
    │ │Prom  │  │Grafana │  │ELK/Kibana│   │
    │ │etheus│  │        │  │          │   │
    │ └──────┘  └────────┘  └──────────┘   │
    └──────────────────────────────────────┘

Network Policy Flow

All components are isolated with strict network policies:

Default deny all ingress/egress
Gateway can receive external traffic
Services communicate only with authorized peers
Database access limited to backend services

Quick Start

Prerequisites

# Required
- Kubernetes cluster (v1.24+)
- kubectl CLI
- Helm (optional, for templating)

# Cluster access
kubectl cluster-info
kubectl get nodes

Verify installation

kubectl get all -n rbyapp-svc

Documentation Structure

Document	Purpose	Key Topics
Namespace & RBAC	Foundation setup	Namespace, RBAC, quotas, service accounts
Gateway Deployment	API Gateway	Nginx reverse proxy, rate limiting, routing
Microservices Deployment	Core services	4 microservices, deployments, services, HPA
Frontend Deployment	Frontend app	Svelte deployment, web server setup
Network Policies	Network security	Ingress/egress rules, service isolation
Storage & Database	Data persistence	PostgreSQL, Redis, backups, PVC
Monitoring & Logging	Observability	Prometheus, Grafana, ELK, alerting
Ingress & API Gateway	External access	Ingress, TLS/SSL, certificate management
Deployment Strategies	CI/CD & operations	Rolling updates, blue-green, canary, rollback

Prerequisites: Kubernetes Cluster Requirements

# Minimum node requirements
- CPU: 4 cores per node
- Memory: 8Gi per node
- Storage: 100Gi for databases
- Nodes: 3 (for high availability)

# Required Kubernetes versions
- v1.24 or later
- preferably v1.27+

# Add-ons to install
- metrics-server (for HPA)
- ingress-nginx (for external access)
- cert-manager (for SSL/TLS)
- prometheus-operator (for monitoring)

Installation

# 1. Check cluster prerequisites
kubectl version --short
kubectl get nodes -o wide

# 2. Install metrics-server (if not present)
kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml

# 3. Install ingress-nginx
helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
helm install ingress-nginx ingress-nginx/ingress-nginx \
  --namespace ingress-nginx --create-namespace

# 4. Install cert-manager
kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.13.0/cert-manager.yaml

# 5. Install prometheus-operator (optional, for monitoring)
helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
helm install kube-prometheus-stack prometheus-community/kube-prometheus-stack \
  --namespace monitoring --create-namespace

Local Development (Minikube)

# Start minikube with sufficient resources
minikube start --cpus 4 --memory 8192 --disk-size 50gb

# Enable required addons
minikube addons enable metrics-server
minikube addons enable ingress

# Get minikube IP
minikube ip

Validation

Comprehensive Health Check

#!/bin/bash

NAMESPACE="rbyapp-svc"

echo "=== Health Check ==="

# 1. Namespace
echo "1. Checking namespace..."
kubectl get namespace $NAMESPACE

# 2. Pods
echo "2. Checking pods..."
kubectl get pods -n $NAMESPACE

# 3. Services
echo "3. Checking services..."
kubectl get svc -n $NAMESPACE

# 4. Deployments
echo "4. Checking deployments..."
kubectl get deployments -n $NAMESPACE

# 5. StatefulSets
echo "5. Checking StatefulSets..."
kubectl get statefulsets -n $NAMESPACE

# 6. PVCs
echo "6. Checking storage..."
kubectl get pvc -n $NAMESPACE

# 7. Network Policies
echo "7. Checking network policies..."
kubectl get networkpolicies -n $NAMESPACE

# 8. Ingress
echo "8. Checking ingress..."
kubectl get ingress -n $NAMESPACE

# 9. Pod logs
echo "9. Checking pod logs..."
kubectl logs -n $NAMESPACE -l app=rbyapp-gateway --tail=10

# 10. Pod connectivity
echo "10. Testing pod connectivity..."
POD=$(kubectl get pods -n $NAMESPACE -l app=rbyapp-gateway -o jsonpath='{.items[0].metadata.name}')
kubectl exec -n $NAMESPACE $POD -- curl -s http://rbyapp-svc-account:8000/health

echo "✓ Health check complete!"

Test Individual Services

# Test gateway
kubectl exec -n rbyapp-svc deployment/rbyapp-gateway -- curl -s http://localhost:80/health

# Test account service
kubectl exec -n rbyapp-svc deployment/rbyapp-svc-account -- curl -s http://localhost:8000/health

# Test core service
kubectl exec -n rbyapp-svc deployment/rbyapp-svc-core -- curl -s http://localhost:8002/actuator/health

# Test frontend
kubectl exec -n rbyapp-svc deployment/rbyapp-frontend -- curl -s http://localhost:3000/health

Port Forward for Local Testing

# Frontend
kubectl port-forward svc/rbyapp-frontend 3000:3000 -n rbyapp-svc
# Visit http://localhost:3000

# Gateway
kubectl port-forward svc/rbyapp-gateway 80:80 -n rbyapp-svc
# Visit http://localhost/health

# Grafana (if deployed)
kubectl port-forward svc/grafana 3001:3000 -n rbyapp-svc
# Visit http://localhost:3001 (admin/prom-operator)

# Kibana (if deployed)
kubectl port-forward svc/kibana 5601:5601 -n rbyapp-svc
# Visit http://localhost:5601

Troubleshooting

Common Issues

1. Pods not starting

# Check pod status
kubectl describe pod <pod-name> -n rbyapp-svc

# Check events
kubectl get events -n rbyapp-svc --sort-by='.lastTimestamp'

# View logs
kubectl logs <pod-name> -n rbyapp-svc

2. ImagePullBackOff

# Ensure Docker image is available
docker pull your-registry/rbyapp-svc-core:latest

# Check image pull secrets
kubectl get secrets -n rbyapp-svc | grep dockercfg

3. Network connectivity issues

# Test DNS
kubectl run -it --rm debug --image=busybox:1.28 -n rbyapp-svc -- sh
# Inside container:
nslookup rbyapp-svc-account
wget -O- http://rbyapp-svc-account:8000/health

# Check network policies
kubectl get networkpolicies -n rbyapp-svc

4. Storage issues

# Check PVC status
kubectl get pvc -n rbyapp-svc

# Describe PVC
kubectl describe pvc postgres-data-pvc -n rbyapp-svc

# Check storage class
kubectl get storageclass

5. Database connection issues

# Test database connectivity
kubectl exec -it postgres-0 -n rbyapp-svc -- psql -U postgres -c "SELECT 1"

# Check database logs
kubectl logs postgres-0 -n rbyapp-svc

# Verify secrets
kubectl get secret rbyapp-core-secrets -n rbyapp-svc -o jsonpath='{.data.datasource-url}' | base64 -d

Debug Commands

# Detailed pod information
kubectl get pods -n rbyapp-svc -o wide

# Pod resource usage
kubectl top pods -n rbyapp-svc

# Node resource usage
kubectl top nodes

# Detailed events
kubectl get events -n rbyapp-svc -o wide

# Check HPA status
kubectl get hpa -n rbyapp-svc
kubectl describe hpa rbyapp-gateway-hpa -n rbyapp-svc

# View API server logs
kubectl logs -n kube-system -l component=kube-apiserver

# Describe namespace
kubectl describe namespace rbyapp-svc

Next Steps

Configure CI/CD: Set up ArgoCD or Flux for GitOps
Setup monitoring: Configure Prometheus scraping and Grafana dashboards
Enable backups: Implement regular database backups
Configure logging: Set up centralized logging with ELK or Loki
Implement security: Add pod security policies and RBAC fine-tuning
Load testing: Use k6 or Apache Bench for performance testing
Multi-region setup: Replicate infrastructure across regions for HA

Name		Name	Last commit message	Last commit date
Latest commit History 3 Commits
implementations		implementations
00_namespace_and_rbac.md		00_namespace_and_rbac.md
01_gateway_deployment.md		01_gateway_deployment.md
02_microservices_deployment.md		02_microservices_deployment.md
03_frontend_deployment.md		03_frontend_deployment.md
04_network_policies.md		04_network_policies.md
05_storage_and_databases.md		05_storage_and_databases.md
06_monitoring_logging.md		06_monitoring_logging.md
07_ingress_and_api_gateway.md		07_ingress_and_api_gateway.md
08_deployment_strategies.md		08_deployment_strategies.md
README.md		README.md

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rbyapp-svc Kubernetes Implementation - A Case Study

📋 Table of Contents

Overview

Architecture

High-Level System Design

Network Policy Flow

Quick Start

Prerequisites

Verify installation

Documentation Structure

Prerequisites: Kubernetes Cluster Requirements

Installation

Local Development (Minikube)

Validation

Comprehensive Health Check

Test Individual Services

Port Forward for Local Testing

Troubleshooting

Common Issues

1. Pods not starting

2. ImagePullBackOff

3. Network connectivity issues

4. Storage issues

5. Database connection issues

Debug Commands

Next Steps

Support & Additional Resources

Documentation

Tools

Community

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