Kubernetes Tutorial

Master Kubernetes fundamentals with our comprehensive tutorial. Learn container orchestration, deployment strategies, and cluster management through practical examples.

Video Tutorial

Introduction to Kubernetes

Kubernetes (K8s) is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications. It groups containers into logical units for easy management and discovery.

Examples:

kubectl version

Check your Kubernetes client and server version

kubectl cluster-info

Display cluster information

kubectl get nodes

List all nodes in the cluster

Pods - The Smallest Deployable Units

Pods are the smallest deployable units in Kubernetes. A Pod represents a single instance of a running process in your cluster and can contain one or more containers.

Examples:

kubectl run nginx --image=nginx

Create a simple pod running nginx

kubectl get pods

List all pods in the current namespace

kubectl get pods -o wide

List pods with additional information (IP, Node, etc.)

kubectl describe pod nginx

Get detailed information about a specific pod

kubectl logs nginx

View logs from a pod

kubectl exec -it nginx -- /bin/bash

Execute interactive shell inside a pod

kubectl delete pod nginx

Delete a pod

Deployments - Managing Application Lifecycle

Deployments provide declarative updates for Pods and ReplicaSets. They manage the rollout of new versions and can automatically roll back if something goes wrong.

Examples:

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

Create a deployment with 3 replicas

kubectl get deployments

List all deployments

kubectl scale deployment nginx --replicas=5

Scale a deployment to 5 replicas

kubectl set image deployment/nginx nginx=nginx:1.21

Update the image of a deployment

kubectl rollout status deployment/nginx

Check the rollout status of a deployment

kubectl rollout undo deployment/nginx

Rollback to the previous deployment version

Services - Exposing Applications

Services provide a stable network endpoint to access a set of Pods. They enable load balancing and service discovery within the cluster.

Examples:

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

Expose a deployment as a ClusterIP service (internal only)

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

Expose a deployment as a NodePort service (external access)

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

Expose a deployment as a LoadBalancer service (cloud provider)

kubectl get services

List all services

kubectl describe service nginx

Get detailed information about a service

ConfigMaps and Secrets

ConfigMaps store non-confidential configuration data, while Secrets store sensitive information like passwords and API keys.

Examples:

kubectl create configmap app-config --from-literal=APP_ENV=production

Create a ConfigMap from literal values

kubectl create configmap app-config --from-file=config.properties

Create a ConfigMap from a file

kubectl get configmaps

List all ConfigMaps

kubectl create secret generic db-password --from-literal=password=mypassword

Create a Secret from literal values

kubectl get secrets

List all Secrets

Namespaces - Organizing Resources

Namespaces provide a way to divide cluster resources between multiple users or teams. They're ideal for environments with many users spread across multiple teams or projects.

Examples:

kubectl get namespaces

List all namespaces

kubectl create namespace development

Create a new namespace

kubectl get pods --namespace=development

List pods in a specific namespace

kubectl config set-context --current --namespace=development

Set default namespace for current context

kubectl delete namespace development

Delete a namespace (and all resources in it)

YAML Manifests - Declarative Configuration

Kubernetes resources are typically defined using YAML files. This allows for version control and reproducible deployments.

Examples:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.21
        ports:
        - containerPort: 80

A basic Deployment manifest apiVersion: API version kind: Resource type metadata: Resource metadata spec: Desired state specification

kubectl apply -f deployment.yaml

Apply a YAML manifest to create/update resources

kubectl delete -f deployment.yaml

Delete resources defined in a YAML file

kubectl get deployment nginx-deployment -o yaml

Export a resource as YAML

Monitoring and Debugging

Kubernetes provides various commands to monitor and debug your applications running in the cluster.

Examples:

kubectl top nodes

Display resource usage (CPU/Memory) of nodes

kubectl top pods

Display resource usage of pods

kubectl get events

List cluster events

kubectl logs -f nginx

Stream logs from a pod in real-time -f: Follow log output

kubectl port-forward pod/nginx 8080:80

Forward local port 8080 to pod port 80 for testing

kubectl describe pod nginx

Get detailed information and events for a pod

Quick Reference

Essential Commands

kubectl get pods - List pods
kubectl apply -f - Apply config
kubectl logs - View logs
kubectl describe - Get details

Best Practices

✓ Use namespaces for organization
✓ Define resource limits
✓ Use liveness/readiness probes
✓ Version control your manifests