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🚀 Deploying Scalable WordPress on Raspberry Pi Cluster with K3s and Kubernetes 🖥️

OSbooter

12/08/2024

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Welcome to the exciting world of Kubernetes! 🌐 In this guide, we’ll show you how to build a scalable infrastructure using K3s on Raspberry Pi, perfect for hosting a WordPress site. We’ll cover everything from setup to scaling and monitoring, all using lightweight Raspberry Pis.

🎯 Objectives Our mission is simple: create a powerful, scalable infrastructure that effortlessly handles WordPress deployment. Ready to roll up your sleeves? Let’s dive in!

🛠️ What You’ll Need

Hardware:

• 5 Raspberry Pis (or just 1 if you’re starting small)
• Router & Switch
• SD Cards & Ethernet Cables
• Power Supply for each Pi
• External Drive for backups

Software:

• Win32 Disk Imager for disk setup
• K3s for ARM architecture
• Raspberry Pi OS Lite 64-bit

Knowledge:

• Basics of Linux, Kubernetes, and Networking 🧠

📦 Step 1: Setting Up Raspberry Pis

1. Prepare Your Hardware:
   • Power up your Raspberry Pis and connect them to the network.
2. Install the OS:
   • Use Raspberry Pi Imager to flash Raspberry Pi OS Lite (64-bit) onto SD cards.
   • Insert the SD card, power on the Pi, and complete the initial setup.
3. Network Configuration:
   • Edit network settings on each Pi to assign static IPs. This ensures stable communication between nodes.
   • Example:
     sudo nano /etc/network/interfaces
auto eth0 iface eth0
inet static
address 192.168.1.2
netmask 255.255.255.0
gateway 192.168.1.1
   • Save and restart the network service.
4. Enable SSH Access:
   • SSH allows remote access to each Pi. Activate it with:
     sudo raspi-config

🏗️ Step 2: Master Node Configuration

1. Install K3s on Master Node:
   • Log into the master Pi and install K3s with:
     curl -sfL https://get.k3s.io | sh -
2. Configure Master Node Components:
   • Export the kubeconfig file:
     export KUBECONFIG=/etc/rancher/k3s/k3s.yaml
   • Install Helm (Kubernetes package manager):
     sudo snap install helm --classic helm init

🌍 Step 3: Setting Up Worker Nodes

1. Install K3s on Worker Nodes:
   • SSH into each worker Pi and install K3s, joining them to the cluster:
     curl -sfL https://get.k3s.io | K3S_URL=https://<master-ip>:6443 K3S_TOKEN=<node-token> sh -
2. Verify Node Status:
   • On the master node, check if all nodes are ready:
     sudo k3s kubectl get nodes

🌐 Step 4: Network Configuration

1. Set Static IPs:
   • Consistent IPs are key for smooth operation. Set these in the /etc/network/interfaces file.
2. Troubleshoot Connectivity:
   • If issues arise, use ping tests between nodes and ensure SSH works.
   • Command:
     ping <other-node-ip>

🗄️ Step 5: Persistent Volume Setup

1. Create Persistent Volumes (PVs):
   • Define storage needs in a YAML file:
     apiVersion: v1 kind:
PersistentVolume metadata:
name: pv-local
spec: capacity:
storage: 1Gi
accessModes: - ReadWriteOnce
hostPath: path: "/mnt/data"
   • Apply with:
     sudo k3s kubectl apply -f pv.yaml
2. Test PVs:
   • Deploy a test pod to ensure data persistence.

🌟 Step 6: Deploy WordPress on Kubernetes

1. Create Deployment YAML:
   • Example WordPress YAML:
2. 
   apiVersion: apps/v1 kind:
Deployment metadata:
name: wordpress
spec:
replicas: 1
selector:
matchLabels:
app: wordpress
template: metadata:
labels:
app: wordpress
spec:
containers:
- name: wordpress
image: wordpress:latest
env:
- name: WORDPRESS_DB_HOST
value: mysql-service
- name: WORDPRESS_DB_PASSWORD
valueFrom: secretKeyRef:
name: mysql-secret
key: password
---
apiVersion: v1
kind: Service metadata:
name: wordpress-service
spec:
selector:
app: wordpress ports:
- protocol:
TCP port: 80
targetPort: 80
type: LoadBalancer
3. Access WordPress:
   • Open your browser and navigate to the external IP assigned to the WordPress service.

📈 Step 7: Scaling WordPress Deployment

1. Enable Autoscaling:
   • Configure autoscaling with a Horizontal Pod Autoscaler (HPA):
     apiVersion: autoscaling/v2beta2 kind: HorizontalPodAutoscaler metadata: name: wordpress-hpa spec: scaleTargetRef: apiVersion: apps/v1 kind: Deployment name: wordpress minReplicas: 1 maxReplicas: 5 metrics: - type: Resource resource: name: cpu targetAverageUtilization: 80
2. Test Scalability:
   • Use load testing tools to simulate traffic and monitor scaling:
     ab -n 10000 -c 10 http://<wordpress-service-ip>/

📊 Step 8: Monitoring with Prometheus and Grafana

1. Deploy Prometheus:
   • Collect metrics to monitor your cluster’s performance.
2. Set Up Grafana:
   • Visualize metrics using Grafana dashboards. Import Kubernetes dashboards for detailed insights.

🎉 Conclusion

You’ve successfully deployed a scalable WordPress site using Kubernetes on Raspberry Pi! This guide is just the beginning. Keep exploring and tweaking your setup to match your needs. 🌍

Happy clustering! 🎉

🔗 Useful Resources:

• Kubernetes Stateful Application Guide
• K3s Storage Docs
• YouTube Tutorial Playlist