High availability cluster setup in Kubernetes - Mini Project: Build & Apply

High Availability Cluster Setup

📖 Scenario: You are working as a DevOps engineer tasked with setting up a high availability Kubernetes cluster. This cluster will ensure that your application stays online even if one of the master nodes fails.Think of it like having multiple backup generators at home. If one stops working, the others keep the lights on without interruption.

🎯 Goal: Build a simple Kubernetes cluster configuration with multiple master nodes for high availability. You will create the initial cluster configuration, add a control plane endpoint, configure multiple master nodes, and finally verify the cluster status.

📋 What You'll Learn

Create a basic Kubernetes cluster configuration file named kubeadm-config.yaml with a single master node.

Add a control plane endpoint to enable high availability.

Add two additional master nodes to the configuration.

Verify the cluster status using kubectl commands.

💡 Why This Matters

🌍 Real World

High availability clusters keep applications running without interruption even if some servers fail, which is critical for business continuity.

💼 Career

DevOps engineers often set up and maintain highly available Kubernetes clusters to ensure reliable application deployment and uptime.

1

Create initial cluster configuration

Create a file named kubeadm-config.yaml with the following content exactly: a ClusterConfiguration kind, Kubernetes version v1.26.0, and a single control plane endpoint set to "localhost:6443". Include one master node with the name master1 and IP 192.168.1.10 under nodes.

Kubernetes

# Create kubeadm-config.yaml with ClusterConfiguration, version v1.26.0, controlPlaneEndpoint localhost:6443, and one master node named master1 with IP 192.168.1.10
# Your code here

Need a hint?

Use YAML format. The controlPlaneEndpoint is the address clients use to connect to the cluster.

2

Add control plane endpoint for high availability

Modify kubeadm-config.yaml to change the controlPlaneEndpoint from "localhost:6443" to "ha-cluster.example.com:6443" to enable high availability access point.

Kubernetes

apiVersion: kubeadm.k8s.io/v1beta3
kind: ClusterConfiguration
kubernetesVersion: v1.26.0
controlPlaneEndpoint: "localhost:6443"
nodes:
  - name: master1
    ip: 192.168.1.10
    role: master
# Change controlPlaneEndpoint to ha-cluster.example.com:6443
# Your code here

Need a hint?

The controlPlaneEndpoint should be a DNS name or IP that points to your load balancer for masters.

3

Add two more master nodes

Add two more master nodes to kubeadm-config.yaml under nodes: master2 with IP 192.168.1.11 and master3 with IP 192.168.1.12. Both should have the role master.

Kubernetes

apiVersion: kubeadm.k8s.io/v1beta3
kind: ClusterConfiguration
kubernetesVersion: v1.26.0
controlPlaneEndpoint: "ha-cluster.example.com:6443"
nodes:
  - name: master1
    ip: 192.168.1.10
    role: master
# Add master2 and master3 nodes with their IPs and role master
# Your code here

Need a hint?

Indent the new nodes properly under nodes in YAML.

4

Verify cluster status

Run the command kubectl get nodes to display the status of all nodes in the cluster.

Kubernetes

# Run kubectl get nodes to check cluster status
# Your code here

Need a hint?

Make sure your cluster is running and kubectl is configured to connect to it.