K8-Simplified 🚀

Modernizing. Streamlining. Deploying.

K8-Simplified is a lightweight, automated bash utility designed to bootstrap a production-ready Kubernetes cluster on RHEL/CentOS-based systems (CentOS, RHEL, Amazon Linux) with minimal manual intervention.

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✨ Features

• Automated Preparation: Automatically handles swap disabling, kernel module loading (overlay, br_netfilter), and sysctl network configuration.
• Optimized Container Runtime: Installs and configures Containerd or Docker (via cri-dockerd). Includes specialized registry mirrors to bypass rate limits.
• Dual Role Support: Single script for both Master (Control Plane) and Worker node initialization.
• Modular Architecture: Clean separation of concerns with specialized modules for environment prep, runtime config, and package management.
• Network Ready: Integrated configuration for Calico CNI (v3.27.3) for instant cross-node communication.
• Latest Stable Version: Configured for Kubernetes v1.29.

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🏗 Project Architecture

graph TD
    Main[ks_installer.sh] --> Common[scripts/common.sh]
    Main --> Env[scripts/env_prep.sh]
    Main --> Runtime[scripts/runtime.sh]
    Main --> K8s[scripts/k8s_install.sh]

    K8s --> Role{Role Setup}
    Role -- Master --> MasterSetup[scripts/master_setup.sh]
    Role -- Worker --> WorkerSetup[scripts/worker_setup.sh]

    subgraph "Infrastructure Prep"
        Env
        Runtime
    end

    subgraph "Kubernetes Core"
        K8s
        MasterSetup
        WorkerSetup
    end

    style Main fill:black,stroke:#333,stroke-width:4px
    style Role fill:black,stroke:#333,stroke-dasharray: 5 5

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The project has been modularized for better maintainability:

k8-simplified/
├── ks_installer.sh       # Main entry point (orchestrator)
├── banner.png            # Project banner
├── scripts/              # Modular component scripts
│   ├── common.sh         # Shared utilities and configuration
│   ├── env_prep.sh       # System prep (swap, kernel, sysctl)
│   ├── runtime.sh        # Containerd installation & config
│   ├── k8s_install.sh    # Kubernetes repos & packages
│   ├── master_setup.sh   # Master-specific initialization
│   └── worker_setup.sh   # Worker-specific join logic
└── README.md             # This documentation

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📋 Prerequisites

• OS: RHEL, CentOS 7/8, or Amazon Linux 2/2023.
• Privileges: Root or sudo access is required.
• Resources:
  • Master: 2 vCPUs, 2GB RAM minimum.
  • Worker: 1 vCPU, 1GB RAM minimum.
• Network: Internet access to pull images and packages.

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🚀 Quick Start

1. Preparation

Clone this repository and ensure the installer is executable:

git clone <your-repo-url>
cd k8-simplified
chmod +x ks_installer.sh

2. Master Node Setup

Run the following command on the node intended to be the control plane:

# Default (containerd)
sudo ./ks_installer.sh master

# Specify Docker
sudo ./ks_installer.sh master <MASTER_IP> docker

Once complete, the script will output a kubeadm join command. Copy this command for the next step.

3. Worker Node Setup

Run the following command on each worker node:

# Default (containerd)
sudo ./ks_installer.sh worker <MASTER-IP>
# Example: sudo ./ks_installer.sh worker 192.168.1.10

# Specify Docker
sudo ./ks_installer.sh worker <MASTER-IP> docker
# Example: sudo ./ks_installer.sh worker 192.168.1.10 docker

When prompted, paste the kubeadm join command generated by the Master node.

Example of what you'll paste:

kubeadm join 192.168.1.10:6443 --token abcdef.1234567890abcdef \
    --discovery-token-ca-cert-hash sha256:7c22...

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✅ Verification

After setting up all nodes, run this on the Master node to verify the cluster status:

kubectl get nodes

You should see all your nodes listed with a status of Ready.

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🛠 Technical Details

Versions Used

• Kubernetes: v1.29
• CNI: Calico v3.27.3
• Runtimes: Containerd, Docker (with cri-dockerd shim)

Automatic Registry Mirroring

Whether you choose Containerd or Docker, the script automatically configures a mirror for registry.k8s.io to avoid ImagePullBackOff issues caused by public registry rate limits.

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📄 License

This project is licensed under the MIT License - see the LICENSE file for details.