Installation and Architecture Overview

Core Components

• API Server: Handles cluster operations and user requests
• Controller Manager: Maintains desired pod states and self-healing
• Scheduler: Assigns pods to worker nodes
• etcd: Distributed key-value store for cluster state

Installation Methods

yum: Simple but outdated versions
kubeadm: Recommended for production with network requirements
Minikube: Single-node for development/testing
Manual binaries: Complex but customizable
Source compilation: Advanced method requiring Go environment

Environment Specificasion

System Configuration

hostnamectl set-hostname k8s-control
hostnamectl set-hostname k8s-worker
systemctl disable firewalld --now
setenforce 0

Master Node Setup

yum install -y etcd kubernetes-master
systemctl enable etcd kube-apiserver kube-controller-manager kube-scheduler
systemctl start etcd kube-apiserver

Worker Node Setup

yum install -y kubernetes-node
systemctl enable kubelet kube-proxy
systemctl start kubelet

Container Networking

yum install -y flannel docker
etcdctl set /coreos/network/config '{"Network":"10.100.0.0/16"}'
systemctl restart flannel docker kubelet

Private Registry Configuration

docker run -d -p 5000:5000 --restart=always --name registry registry:2
cat > /etc/docker/daemon.json <<EOF
{"insecure-registries":["192.168.1.101:5000"]}
EOF
systemctl restart docker

Key Features and Resource Types

Kubernetes Capabilities

• Self-healing pod restart and rescheduling
• Horizontal autoscaling based on metrics
• Service discovery with DNS and load balancing
• Rolling updates with automated rollback

Pod Resource Example

apiVersion: v1
kind: Pod
metadata:
  name: webserver
  labels:
    tier: frontend
spec:
  containers:
  - name: nginx
    image: private-registry:5000/nginx:stable
    ports:
    - containerPort: 8080

ReplicaController Operations

kubectl scale rc frontend --replicas=5
kubectl rolling-update frontend --image=nginx:1.20 --update-period=30s

Deployment Management

kubectl create deployment backend --image=redis:6 --replicas=3
kubectl set image deployment/backend redis=redis:7-alpine
kubectl rollout undo deployment/backend --to-revision=2

Service Exposure

apiVersion: v1
kind: Service
metadata:
  name: web-service
spec:
  type: NodePort
  ports:
  - port: 80
    nodePort: 30080
  selector:
    app: webserver

Persistent Storage Implementation

Persistent Volume with NFS

apiVersion: v1
kind: PersistentVolume
metadata:
  name: database-storage
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  nfs:
    path: /exports/db
    server: 192.168.1.100

Data base Deployment with PVC

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
spec:
  template:
    spec:
      containers:
      - name: database
        image: mysql:8.0
        volumeMounts:
        - name: db-vol
          mountPath: /var/lib/mysql
      volumes:
      - name: db-vol
        persistentVolumeClaim:
          claimName: mysql-pvc

Horizontal Autoscaling

kubectl autoscale deployment worker --min=2 --max=10 --cpu-percent=80
kubectl get hpa worker -w

Atuoscaling Manifest

apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
  name: api-autoscaler
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: api-server
  minReplicas: 3
  maxReplicas: 15
  targetCPUUtilizationPercentage: 70