Kubernetes

Chapter 59: Kubernetes Basics

Overview

This chapter covers Kubernetes container orchestration basics.

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59.1 Kubernetes Architecture

Components

              Kubernetes Architecture
+------------------------------------------------------------------+
|                                                                   |
|   +------------------+                                          |
|   |   Control Plane  |                                          |
|   | +--------------+ |                                          |
|   | | kube-apiserver|                                          |
|   | | etcd         |                                          |
|   | | kube-scheduler|                                          |
|   | | kube-controller|                                          |
|   | +--------------+ |                                          |
|   +------------------+                                          |
|           |                                                      |
|           |                                                      |
|   +------------------+     +------------------+                |
|   |   Worker Nodes    |     |   Worker Nodes    |                |
|   | +--------------+ |     | +--------------+ |                |
|   | | kubelet      | |     | | kubelet      | |                |
|   | | kube-proxy   | |     | | kube-proxy   | |                |
|   | | containerd   | |     | | containerd   | |                |
|   | +--------------+ |     | +--------------+ |                |
|   +------------------+     +------------------+                |
|                                                                   |
+------------------------------------------------------------------+

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59.2 kubectl

Basic Commands

# Cluster info
kubectl cluster-info
kubectl get nodes

# Pods
kubectl get pods
kubectl get pods -o wide
kubectl describe pod pod_name
kubectl logs pod_name
kubectl exec -it pod_name -- /bin/sh

# Deployments
kubectl get deployments
kubectl create deployment nginx --image=nginx
kubectl scale deployment nginx --replicas=3
kubectl rollout status deployment nginx

# Services
kubectl get services
kubectl expose deployment nginx --port=80

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59.3 Pods

Pod Definition

pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  containers:
  - name: nginx
    image: nginx:1.24
    ports:
    - containerPort: 80
    resources:
      limits:
        memory: "128Mi"
        cpu: "500m"
      requests:
        memory: "64Mi"
        cpu: "250m"

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59.4 Deployments

Deployment Example

deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.24
        ports:
        - containerPort: 80

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59.5 Services

Service Types

service.yaml

apiVersion: v1
kind: Service
metadata:
  name: nginx
spec:
  type: ClusterIP  # or NodePort, LoadBalancer
  selector:
    app: nginx
  ports:
  - port: 80
    targetPort: 80

# NodePort example
kubectl expose deployment nginx --type=NodePort

# LoadBalancer
kubectl expose deployment nginx --type=LoadBalancer

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59.6 ConfigMaps and Secrets

ConfigMap

configmap.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
data:
  database_url: "postgres://db:5432/app"
  cache_enabled: "true"

Secret

secret.yaml

apiVersion: v1
kind: Secret
metadata:
  name: db-secret
type: Opaque
stringData:
  username: admin
  password: changeme

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59.7 Namespaces

Namespace Commands

# List namespaces
kubectl get namespaces

# Create namespace
kubectl create namespace dev

# Use namespace
kubectl config set-context --current --namespace=dev

# Get in namespace
kubectl get pods -n dev

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Summary

In this chapter, you learned:

• ✅ Kubernetes architecture
• ✅ kubectl commands
• ✅ Pods
• ✅ Deployments
• ✅ Services
• ✅ ConfigMaps and Secrets
• ✅ Namespaces

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Next Chapter

Chapter 60: Container Security

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Last Updated: February 2026