MariaDB Master/Slave Cluster on Kubernetes (StatefulSet)

This project demonstrates how to deploy a MariaDB master-slave replication setup using Kubernetes StatefulSet and Longhorn for persistent storage.

⚠️ Status: Experimental / Work in Progress

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🚀 Project Overview

This setup consists of:

• A StatefulSet with 2 MariaDB pods:
  • mariadb-0 acts as the master
  • mariadb-1 acts as the slave
• Master/Slave configuration is handled via initContainers and ConfigMap
• Persistent volumes are provisioned dynamically using Longhorn
• Uses ConfigMaps to inject different .cnf and .sql files based on pod index

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📁 Project Structure

• ConfigMap: Contains separate config files and init SQL for master and slave
• StatefulSet: Creates two MariaDB pods with specific initialization logic
• Service: Headless service to allow DNS-based internal communication between pods

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⚙️ Requirements

• Kubernetes cluster (v1.30+ recommended)
• Longhorn installed as the default or named storageClass
• kubectl configured and connected to your cluster

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⚠️ Important Notes

• Default Credentials:
  • root password: 123
  • Replication user: radin
  • Replication password: 123
• Please make sure to change the default passwords before using this in any real environment.
• This project is not production ready. Stability, fault tolerance, and failover mechanisms are still being improved.
• Longhorn is used with ReadWriteMany mode — make sure your Kubernetes setup and Longhorn are properly configured for this.

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🧪 How It Works

• Pod index 0 is detected as the master, and the appropriate configuration is mounted from the ConfigMap
• Pod index 1 is treated as a slave, which connects to the master using the headless service DNS name
• MariaDB image auto-runs the SQL scripts on first initialization

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📦 Deployment Steps

# Create the namespace
kubectl create namespace db

# Apply the config map
kubectl apply -f configmap.yaml

# Deploy the StatefulSet and Service
kubectl apply -f statefulset.yaml
kubectl apply -f service.yaml

Replace the above filenames with your actual manifest filenames if different.

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🤝 Contributions

Contributions, issues and feature requests are welcome!