How to Set Up a 3-Node Kubernetes Cluster on Ubuntu 24.04 LTS Using Oracle VirtualBox

Table of Contents

1. Introduction

2. Prerequisites

3. Step 1: Set Up Virtual Machines

4. Step 2: Install Containerd

5. Step 3: Install Kubernetes Components

6. Step 4: Initialize the Kubernetes Master Node

7. Step 5: Install Calico CNI

8. Step 6: Join Worker Nodes to the Cluster

9. Step 7: Verify the Cluster

10. Conclusion

11. Next Steps

Introduction

Kubernetes is a powerful container orchestration platform that automates the deployment, scaling, and management of containerized applications. Setting up a Kubernetes cluster locally is a great way to learn and experiment with Kubernetes without the need for cloud infrastructure.

In this guide, we’ll use Oracle VirtualBox to create three virtual machines (one master and two worker nodes) running Ubuntu 24.04 LTS. We’ll then install Kubernetes v1.30, configure Containerd as the container runtime, and set up Calico for networking.

Prerequisites

Before we begin, ensure you have the following:

Software Requirements

• Oracle VirtualBox installed on your local machine.

• Ubuntu 24.04 LTS ISO file.

• Stable Internet Connection.

Hardware Requirements

Knowledge Requirements

• Basic understanding of Linux commands.

• Familiarity with networking concepts.

Step 1: Set Up Virtual Machines

1.1 Create Virtual Machines

1. Open Oracle VirtualBox and click New.

2. Create three virtual machines:

   • k8s-master (Master Node)

   • k8s-worker1 (Worker Node 1)

   • k8s-worker2 (Worker Node 2)

3. Assign 2 CPUs, 4GB RAM to the master node, and 2 CPUs, 2GB RAM to the worker nodes.

4. Attach the Ubuntu 24.04 LTS ISO to each VM and complete the installation.

1.2 Configure Network and Static IPs

1. Go to Settings → Network for each VM and set the adapter to Bridged mode.

2. Assign static IPs to each node by editing the Netplan configuration file:

Example configuration for the master node:

3. Apply the changes:

1.3 Disable Swap

Kubernetes requires swap to be disabled. Run the following command on all nodes:

Step 2: Install Containerd

2.1 Install Dependencies

Update the package list and install required dependencies:

2.2 Install and Configure Containerd

1. Install Containerd:

2. Generate the default configuration file:

3. Restart and enable Containerd:

Step 3: Install Kubernetes Components

3.1 Add Kubernetes Repository

Add the Kubernetes repository to your system:

3.2 Install Kubernetes Packages

Install kubeadm, kubelet, and kubectl

Step 4: Initialize the Kubernetes Master Node

4.1 Initialize the Cluster

On the master node, run the following command to initialize the cluster:

Save the join command displayed in the output for adding worker nodes later.

4.2 Configure kubectl

To start using the cluster, configure kubectl:

Step 5: Install Calico CNI

5.1 Apply the Calico Networking Plugin

Install Calico as the CNI plugin:

5.2 Verify Calico Pods

Check that the Calico pods are running:

Step 6: Join Worker Nodes to the Cluster

6.1 Join Worker Nodes

On each worker node, run the join command saved from the master node initialization:

6.2 Verify Nodes

On the master node, check that all nodes have joined the cluster:

Step 7: Verify the Cluster

7.1 Check Node Status

Ensure all nodes are in the Ready state:

7.2 Check Pod Status

Verify that all system pods are running:

Conclusion

Congratulations! 🎉 You’ve successfully set up a 3-node Kubernetes cluster using Ubuntu 24.04 LTS, Oracle VirtualBox, Kubernetes v1.30, Containerd, and Calico CNI. Your cluster is now ready to deploy and manage containerized applications.

Next Steps

✅ Deploy a sample application (e.g., Nginx) to test the cluster.
✅ Install the Kubernetes Dashboard for a graphical interface.
✅ Set up Prometheus and Grafana for cluster monitoring.

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