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What is Kubernetes?

Kubernetes (K8s) is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications.

Key Concepts

1. Container Orchestration

  • Manages multiple containers across multiple hosts
  • Ensures high availability and scalability
  • Handles container lifecycle management

2. Core Features

  • Automated rollouts and rollbacks
  • Service discovery and load balancing
  • Storage orchestration
  • Self-healing
  • Secret and configuration management
  • Horizontal scaling

3. Basic Architecture

Control Plane Components

  1. kube-apiserver: Frontend for Kubernetes control plane
  2. etcd: Key-value store for all cluster data
  3. kube-scheduler: Watches for newly created pods and assigns them to nodes
  4. kube-controller-manager: Runs controller processes

Node Components

  1. kubelet: Ensures containers are running in a Pod
  2. kube-proxy: Maintains network rules on nodes
  3. Container runtime: Software responsible for running containers (e.g., Docker)

4. Basic Objects

  • Pods: Smallest deployable units
  • Services: Expose applications running on pods
  • Volumes: Persistent storage
  • Namespaces: Virtual clusters

Why Use Kubernetes?

  1. Portability
  2. Run applications anywhere (cloud, on-premises)

  3. Consistent environment across development and production

  4. Scalability

  5. Automatically scale applications based on demand

  6. Handle increased traffic efficiently

  7. High Availability

  8. Self-healing capabilities
  9. Automatic rollouts and rollbacks

  10. Load balancing

  11. Container Management

  12. Automated container deployment
  13. Resource optimization
  14. Service discovery and load balancing

Real-World Example

Let's consider a simple web application:

# Simple web application deployment
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - name: web-container
        image: nginx:latest
        ports:
        - containerPort: 80

This example shows: - Deployment of a web application - Running 3 replicas for high availability - Using nginx as the web server - Exposing port 80

Benefits in Practice

  1. Development
  2. Consistent development environment
  3. Easy testing and deployment

  4. Quick rollback if needed

  5. Operations

  6. Automated scaling
  7. Self-healing capabilities

  8. Easy monitoring and logging

  9. Business

  10. Reduced downtime
  11. Better resource utilization
  12. Cost efficiency

Getting Started

To start with Kubernetes: 1. Install a local Kubernetes cluster (Minikube) 2. Learn basic kubectl commands 3. Deploy your first application 4. Explore more advanced features

Next Steps

Continue learning about: - Installing Minikube - Basic kubectl commands - Creating pods and deployments - Setting up services - Managing configurations