Introduction to Kubernetes and installation

What is Kubernetes?

Kubernetes (often abbreviated as K8s) is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications. Originally developed by Google, it is now maintained by the Cloud Native Computing Foundation (CNCF).

Why Use Kubernetes?

Kubernetes provides several key benefits for managing applications in a containerized environment:

• Automated Deployment & Scaling – Easily deploy and scale applications as demand increases or decreases.
• Self-Healing – Automatically restarts failed containers, replaces unresponsive instances, and reschedules workloads as needed.
• Load Balancing – Distributes traffic efficiently to maintain application performance.
• Storage Orchestration – Manages storage needs dynamically with Persistent Volumes (PVs) and Persistent Volume Claims (PVCs).
• Multi-Cloud & Hybrid Cloud Support – Works seamlessly across on-premise, public cloud, and hybrid cloud environments.

Key Components of Kubernetes

1. Master Node – Controls the cluster and manages scheduling, networking, and scaling.
   • API Server – Exposes the Kubernetes API.
   • Scheduler – Assigns workloads to worker nodes.
   • Controller Manager – Ensures desired state is maintained.
   • etcd – Stores cluster configuration data.
2. Worker Nodes – Run the application workloads.
   • Kubelet – Manages the node and communicates with the master node.
   • Container Runtime – Runs the containerized applications (e.g., Docker, containerd).
   • Kube Proxy – Manages networking and load balancing within the cluster.

How Kubernetes Works

Kubernetes organizes applications into Pods, which are the smallest deployable units. A Pod can contain one or multiple containers that share resources like storage and networking. Kubernetes ensures these Pods are running efficiently and are properly distributed across the cluster.

Common Kubernetes Objects

• Pods – The basic unit of deployment in Kubernetes.
• Deployments – Manage replica sets and rolling updates.
• Services – Expose applications running in Pods to the network.
• ConfigMaps & Secrets – Manage configuration data and sensitive information.
• Persistent Volumes (PVs) & Persistent Volume Claims (PVCs) – Handle data storage.
• Ingress – Manage external access to services.

Getting Started with Kubernetes

Prerequisites

To get started with Kubernetes, ensure you have the following:

• A basic understanding of containers and Docker.
• A Linux/macOS/Windows system with virtualization enabled.
• Installed tools: kubectl (Kubernetes CLI), Minikube (for local clusters), or a cloud Kubernetes provider.

Step 1: Install Kubernetes Command-Line Tool (kubectl)

kubectl

is the primary command-line tool for managing Kubernetes clusters. Install it using the following commands:

On Linux

curl -LO "https://dl.k8s.io/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl"
sudo chmod +x kubectl
sudo mv kubectl /usr/local/bin/
kubectl version --client

On macOS (using Homebrew)

brew install kubectl
kubectl version --client

On Windows (using Chocolatey)

choco install kubernetes-cli
kubectl version --client

Step 2: Set Up a Kubernetes Cluster

Option 1: Local Kubernetes Cluster (Using Minikube)

Minikube is a lightweight Kubernetes distribution that runs on your local machine. It is ideal for testing and development.

Install Minikube

curl -LO https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64
sudo install minikube-linux-amd64 /usr/local/bin/minikube

Start Minikube Cluster

minikube start --driver=docker

This command starts a local Kubernetes cluster using Docker as the driver.

Verify Installation

kubectl get nodes

If Minikube is running successfully, you should see a single node in the output.

Option 2: Cloud-Based Kubernetes Cluster

If you want to deploy Kubernetes in the cloud, major providers offer managed Kubernetes services:

• Google Kubernetes Engine (GKE) (Google Cloud)
• Amazon Elastic Kubernetes Service (EKS) (AWS)
• Azure Kubernetes Service (AKS) (Microsoft Azure)

Each provider has a command-line tool to create a cluster quickly. For example, to create a Kubernetes cluster on GKE:

gcloud container clusters create my-cluster --num-nodes=3

Step 3: Deploy Your First Application on Kubernetes

Create a Deployment

A Kubernetes Deployment ensures that a specified number of replicas of a containerized application are running.

Create a simple deployment using Nginx:

kubectl create deployment nginx --image=nginx

Check if the deployment is running:

kubectl get deployments

Expose the Application

To access the application, expose it as a Kubernetes Service:

kubectl expose deployment nginx --type=LoadBalancer --port=80

Get the service details:

kubectl get services

If using Minikube, open the service in the browser:

minikube service nginx

Step 4: Managing Kubernetes Resources

Check Running Pods

kubectl get pods

View Pod Logs

kubectl logs <pod-name>

Scale an Application

To scale the deployment to 3 replicas:

kubectl scale deployment nginx --replicas=3

Verify scaling:

kubectl get pods

Delete a Deployment

kubectl delete deployment nginx

Step 5: Clean Up

If using Minikube, delete the cluster to free up resources:

minikube delete

For cloud-based clusters, delete them using provider-specific commands to avoid unnecessary charges.

Conclusion

Kubernetes simplifies container management, making it an essential tool for modern cloud-native applications. By automating deployment, scaling, and operations, Kubernetes helps developers build resilient, scalable, and efficient applications in any environment.

Read this: Kubernetes Cheat Sheet: 50+ Essential Commands