Kubernetes Multi-Node Cluster Setup, Troubleshooting and Nginx Deployment

Project Overview

This project demonstrates the setup, troubleshooting, and validation of a Kubernetes multi-node cluster consisting of 1 Master Node and 3 Worker Nodes using kubeadm, containerd, and Calico networking.

The project includes cluster initialization, worker node joining, troubleshooting of real-world Kubernetes issues, and deployment of an Nginx application using Kubernetes Deployments and Services.

• 1 Master Node
• 3 Worker Nodes

After creating the cluster, an Nginx application was deployed using Kubernetes Deployment and Service resources.

Environment

• Operating System: Ubuntu Linux
• Virtualization Platform: VMware Workstation
• Kubernetes
• kubeadm
• kubelet
• kubectl
• Containerd
• Calico CNI
• YAML

Cluster Architecture

Master Node
│
├── Worker Node 1
├── Worker Node 2
└── Worker Node 3

Objectives

• Create a multi-node Kubernetes cluster.
• Join worker nodes to the master node.
• Deploy containerized applications.
• Expose applications using Kubernetes Services.
• Manage pods and deployments using kubectl.

Installation Steps

Initialize Kubernetes Master Node

sudo kubeadm init

Configure kubectl

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Generate Join Command kubeadm token create --print-join-command

Join Worker Nodes

kubeadm join <MASTER-IP>:6443 --token <TOKEN> \
--discovery-token-ca-cert-hash sha256:<HASH>

Verify Cluster

kubectl get nodes

Nginx Deployment

Create Deployment

kubectl create deployment nginx-deploy --image=nginx --replicas=3

Verify Pods

kubectl get pods -o wide

Create Expose Service

kubectl expose deployment nginx-deploy --type=NodePort --port=80

Verify Services

kubectl get svc 

Additional Resources

YAML manifests (deployment.yaml and service.yaml) are also included in this repository for Kubernetes resource management and deployment automation.

Project Files

kubernetes-cluster-project/
│
├── deployment.yaml
├── service.yaml
├── README.md
├── commands.md
├── kubernetes_cluster_journey.pdf
├── kubernetes_cluster_troubleshooting_journey.pdf
│
└── screenshots/
    ├── cluster-ready.png
    ├── nodes-output.png
    ├── get-pods.png
    ├── get-services.png
    └── nginx-working.png

Screenshots

Cluster Ready

Nodes Output

Pods Running

Services Running

Nginx Application

Commands Used

Note: Both YAML-based deployment and kubectl CLI deployment methods were practiced during the project.

kubectl get nodes
kubectl get pods
kubectl get svc

kubectl apply -f deployment.yaml
kubectl apply -f service.yaml

kubectl create deployment nginx-deploy --image=nginx --replicas=3
kubectl expose deployment nginx-deploy --type=NodePort --port=80

kubeadm token create --print-join-command 

Project Highlights

• Kubernetes Cluster Setup - Built a multi-node Kubernetes cluster with 1 Master Node and 3 Worker Nodes.
• Container Runtime Configuration - Configured containerd as the container runtime.
• Calico Networking - Installed and configured Calico CNI for cluster networking.
• Worker Node Integration - Joined worker nodes using kubeadm.
• Cluster Troubleshooting - Diagnosed and resolved worker node join failures.
• kubelet Issue Resolution - Fixed kubelet configuration and startup issues.
• Token Discovery Fixes - Resolved JWS signature and token discovery errors.
• Application Deployment - Deployed Nginx using Kubernetes Deployment.
• Service Exposure - Exposed the application through a NodePort Service.
• Cluster Validation - Verified cluster health, networking, and service accessibility.

Skills Demonstrated

• Linux Administration - System management and troubleshooting
• Kubernetes Administration - Cluster deployment and management
• kubeadm Cluster Setup - Multi-node cluster initialization
• Worker Node Management - Node joining and maintenance
• containerd Runtime Configuration - Container runtime setup
• Calico Networking - Kubernetes network configuration
• Cluster Troubleshooting - Issue diagnosis and resolution
• Deployment Management - Application deployment handling
• NodePort Services - Service exposure and access management
• YAML Configuration - Kubernetes resource definitions
• Kubernetes Networking - Cluster communication setup
• System Debugging - Error analysis and troubleshooting

Key Learning Outcomes

• Kubernetes Architecture - Understanding cluster components and overall architecture
• Control Plane and Worker Node Communication - Managing communication between cluster nodes
• kubeadm Cluster Lifecycle Management - Cluster initialization, joining, and maintenance
• Container Runtime Integration - Working with containerd as the container runtime
• Calico Networking - Configuring and troubleshooting Kubernetes networking
• kubelet Troubleshooting - Diagnosing and resolving kubelet-related issues
• Token Discovery Mechanism - Understanding node authentication and cluster joining
• Deployment and Service Management - Managing applications using Deployments and Services
• Kubernetes Debugging Techniques - Identifying and resolving cluster issues effectively

Troubleshooting Experience

During the Kubernetes cluster setup, several real-world issues were encountered and resolved:

Worker Node Join Failure

• kubeadm join became stuck during the discovery phase.
• Generated a fresh join token from the master node.
• Rejoined worker nodes successfully.

kubelet Configuration Issues

• Worker nodes failed to load kubelet configuration files.
• Cleaned old Kubernetes state and reconfigured nodes.
• Restarted kubelet and containerd services.

JWS Signature / Discovery Token Error

• Encountered cluster-info ConfigMap discovery errors.
• Regenerated join tokens and repeated the join process.
• Successfully synchronized worker nodes with the control plane.

Calico Networking Initialization

• Calico pods remained in PodInitializing state.
• Verified pod status and networking configuration.
• Confirmed successful transition to Running state.

Cluster Validation

Successfully verified:

• Master Node Ready
• Worker Node 1 Ready
• Worker Node 2 Ready
• Worker Node 3 Ready

---

Future Enhancements

• Helm Package Management
• Ingress Controller
• Persistent Volumes
• RBAC Configuration
• Prometheus Monitoring
• Grafana Dashboards
• Jenkins CI/CD Pipeline
• Horizontal Pod Autoscaling

Author

Asha