Kubernetes untuk Pemula: Orchestrate Container

# === Install kubectl (CLI untuk Kubernetes) ===

# macOS
brew install kubectl

# Linux
curl -LO "https://dl.k8s.io/release/$(curl -L -s \
  https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
chmod +x kubectl && sudo mv kubectl /usr/local/bin/

# Verifikasi
kubectl version --client

# === Install Minikube (local single-node cluster) ===

# macOS
brew install minikube

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

# Start cluster
minikube start --driver=docker --cpus=2 --memory=4096

# Cek status
minikube status
kubectl cluster-info
kubectl get nodes

# Alternatif: Docker Desktop sudah include Kubernetes
# (Aktifkan di Settings → Kubernetes → Enable Kubernetes)

# Alternatif: kind (Kubernetes in Docker)
# brew install kind
# kind create cluster

# pod.yaml — Pod sederhana dengan satu container
apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  labels:
    app: nginx
    environment: development
    version: "1.0"
spec:
  containers:
    - name: nginx
      image: nginx:1.25-alpine
      ports:
        - containerPort: 80
      resources:
        requests:
          memory: "64Mi"
          cpu: "100m"    # 0.1 CPU core
        limits:
          memory: "128Mi"
          cpu: "250m"    # 0.25 CPU core
      livenessProbe:
        httpGet:
          path: /
          port: 80
        initialDelaySeconds: 10
        periodSeconds: 30
      readinessProbe:
        httpGet:
          path: /
          port: 80
        initialDelaySeconds: 5
        periodSeconds: 10

# multi-container-pod.yaml — Sidecar pattern
apiVersion: v1
kind: Pod
metadata:
  name: web-with-logger
  labels:
    app: web
spec:
  containers:
    # Container utama: web app
    - name: web-app
      image: nginx:1.25-alpine
      volumeMounts:
        - name: shared-logs
          mountPath: /var/log/nginx

    # Sidecar container: log collector
    - name: log-collector
      image: busybox
      command: ['sh', '-c', 'tail -f /var/log/nginx/access.log']
      volumeMounts:
        - name: shared-logs
          mountPath: /var/log/nginx

  # Shared volume antara kedua container
  volumes:
    - name: shared-logs
      emptyDir: {}

# Buat pod dari YAML
kubectl apply -f pod.yaml

# Buat pod langsung (imperative)
kubectl run nginx-pod --image=nginx:1.25-alpine --port=80

# Lihat semua pods
kubectl get pods
kubectl get pods -o wide         # Lebih detail (IP, node)
kubectl get pods --all-namespaces # Semua namespace

# Lihat detail pod
kubectl describe pod nginx-pod

# Lihat log container
kubectl logs nginx-pod
kubectl logs nginx-pod -f        # Follow (live stream)
kubectl logs nginx-pod -c nginx  # Container spesifik

# Masuk ke dalam container
kubectl exec -it nginx-pod -- /bin/sh

# Port forwarding (akses pod dari localhost)
kubectl port-forward nginx-pod 8080:80
# Buka http://localhost:8080

# Hapus pod
kubectl delete pod nginx-pod
kubectl delete -f pod.yaml

# Force delete pod yang stuck
kubectl delete pod nginx-pod --grace-period=0 --force

# === ClusterIP Service (default, internal only) ===
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  type: ClusterIP  # Default — bisa dihilangkan
  selector:
    app: nginx     # Memilih pod dengan label app=nginx
  ports:
    - protocol: TCP
      port: 80           # Port service
      targetPort: 80      # Port container

---
# === NodePort Service (expose di setiap node) ===
apiVersion: v1
kind: Service
metadata:
  name: nginx-nodeport
spec:
  type: NodePort
  selector:
    app: nginx
  ports:
    - protocol: TCP
      port: 80           # Port cluster
      targetPort: 80      # Port container
      nodePort: 30080     # Port di setiap node (30000-32767)

---
# === LoadBalancer Service (cloud provider) ===
apiVersion: v1
kind: Service
metadata:
  name: nginx-lb
spec:
  type: LoadBalancer
  selector:
    app: nginx
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80

# Lihat semua services
kubectl get services
kubectl get svc -o wide

# Service bisa diakses dari pod lain via DNS:
# Format: ..svc.cluster.local
#
# Contoh:
# - nginx-service              (same namespace)
# - nginx-service.default      (explicit namespace)
# - nginx-service.default.svc.cluster.local  (FQDN)

# Test dari dalam pod
kubectl exec -it test-pod -- curl http://nginx-service
kubectl exec -it test-pod -- curl http://nginx-service.default.svc.cluster.local

# Cek endpoints yang di-manage oleh service
kubectl get endpoints nginx-service

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
  labels:
    app: web
    tier: frontend
spec:
  replicas: 3               # Jumlah pod yang diinginkan
  selector:
    matchLabels:
      app: web               # Harus match dengan pod template labels
  strategy:
    type: RollingUpdate      # Strategi update (default)
    rollingUpdate:
      maxSurge: 1            # Maks 1 pod ekstra saat update
      maxUnavailable: 0      # Semua pod harus tersedia
  template:
    metadata:
      labels:
        app: web
        tier: frontend
    spec:
      containers:
        - name: web-app
          image: my-app:v1.0
          ports:
            - containerPort: 3000
          env:
            - name: NODE_ENV
              value: "production"
            - name: DATABASE_URL
              valueFrom:
                secretKeyRef:
                  name: app-secrets
                  key: database-url
          resources:
            requests:
              memory: "128Mi"
              cpu: "100m"
            limits:
              memory: "256Mi"
              cpu: "500m"
          livenessProbe:
            httpGet:
              path: /health
              port: 3000
            initialDelaySeconds: 15
            periodSeconds: 20
            failureThreshold: 3
          readinessProbe:
            httpGet:
              path: /ready
              port: 3000
            initialDelaySeconds: 5
            periodSeconds: 10

# Deploy dari file
kubectl apply -f deployment.yaml

# Lihat deployments
kubectl get deployments
kubectl get deploy -o wide

# Lihat replicasets
kubectl get replicasets

# Lihat pods yang di-manage deployment
kubectl get pods -l app=web

# Rolling update (ubah image)
kubectl set image deployment/web-app web-app=my-app:v2.0

# Cek status rollout
kubectl rollout status deployment/web-app

# Lihat history rollout
kubectl rollout history deployment/web-app

# Rollback ke revisi sebelumnya
kubectl rollout undo deployment/web-app

# Rollback ke revisi spesifik
kubectl rollout undo deployment/web-app --to-revision=2

# Scale deployment
kubectl scale deployment/web-app --replicas=5

# Edit deployment langsung
kubectl edit deployment/web-app

# Lihat semua namespaces
kubectl get namespaces

# Default namespaces di Kubernetes:
# default         — Namespace default jika tidak dispesifikasi
# kube-system     — Komponen sistem Kubernetes
# kube-public     — Resource publik (auto-created)
# kube-node-lease — Heartbeat untuk node

# Buat namespace baru
kubectl create namespace development
kubectl create namespace production

# Atau dari YAML
cat <
      

# === CONTEXT & CLUSTER ===
kubectl config get-contexts         # Lihat semua context
kubectl config use-context minikube # Switch context
kubectl cluster-info                # Info cluster

# === CREATE & APPLY ===
kubectl apply -f manifest.yaml      # Create/Update resource
kubectl create deployment nginx --image=nginx  # Imperative
kubectl create secret generic my-secret \
  --from-literal=password=abc123               # Create secret

# === GET (list resources) ===
kubectl get pods                    # Pods di current namespace
kubectl get pods -A                 # Semua namespace
kubectl get pods -o wide            # Detail tambahan (IP, node)
kubectl get pods -o yaml            # Output dalam YAML
kubectl get pods -l app=web         # Filter label
kubectl get pods --field-selector=status.phase=Running
kubectl get all                     # Semua resource

# === DESCRIBE (detail + events) ===
kubectl describe pod nginx-pod
kubectl describe service web-svc
kubectl describe node minikube

# === LOGS ===
kubectl logs nginx-pod              # Log container
kubectl logs nginx-pod -f           # Follow (live)
kubectl logs nginx-pod --tail=100   # 100 baris terakhir
kubectl logs nginx-pod -c my-sidecar # Container spesifik

# === EXEC (masuk container) ===
kubectl exec -it nginx-pod -- /bin/sh
kubectl exec -it nginx-pod -- bash

# === DEBUG ===
kubectl port-forward pod/nginx-pod 8080:80
kubectl port-forward svc/web-svc 3000:80
kubectl top pods                    # Resource usage
kubectl top nodes                   # Node resource usage

# === EDIT & PATCH ===
kubectl edit deployment web-app     # Edit di editor
kubectl patch deployment web-app \
  -p '{"spec":{"replicas":5}}'     # Quick patch

# === DELETE ===
kubectl delete pod nginx-pod
kubectl delete -f manifest.yaml
kubectl delete pods --all           # Semua pods
kubectl delete pods --all -n dev    # Di namespace tertentu

# === DIFF & DRY RUN ===
kubectl diff -f manifest.yaml       # Lihat perubahan
kubectl apply -f manifest.yaml --dry-run=client

# === OUTPUT FORMATTING ===
kubectl get pods -o json            # JSON
kubectl get pods -o yaml            # YAML
kubectl get pods -o custom-columns=\
  'NAME:.metadata.name,STATUS:.status.phase'

# === LABELS & ANNOTATIONS ===
kubectl label pod nginx-pod env=prod
kubectl annotate pod nginx-pod note="test"

# configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
data:
  # Key-value pairs
  NODE_ENV: "production"
  LOG_LEVEL: "info"
  API_URL: "https://api.example.com"
  PORT: "3000"

  # File content
  nginx.conf: |
    server {
      listen 80;
      server_name example.com;
      location / {
        proxy_pass http://localhost:3000;
      }
    }

---
# Menggunakan ConfigMap di Pod
apiVersion: v1
kind: Pod
metadata:
  name: app-pod
spec:
  containers:
    - name: app
      image: my-app:v1.0
      # Method 1: Env vars dari ConfigMap
      envFrom:
        - configMapRef:
            name: app-config
      # Method 2: Env var spesifik
      env:
        - name: NODE_ENV
          valueFrom:
            configMapKeyRef:
              name: app-config
              key: NODE_ENV
      # Method 3: Mount sebagai file
      volumeMounts:
        - name: config-volume
          mountPath: /etc/nginx/conf.d
  volumes:
    - name: config-volume
      configMap:
        name: app-config
        items:
          - key: nginx.conf
            path: default.conf

# Membuat Secret
# Method 1: kubectl imperative
kubectl create secret generic app-secrets \
  --from-literal=DB_PASSWORD=mysecurepass \
  --from-literal=API_KEY=abc123xyz \
  --from-literal=JWT_SECRET=myjwtsecret

# Method 2: YAML (nilai harus base64 encoded)
apiVersion: v1
kind: Secret
metadata:
  name: app-secrets
type: Opaque
data:
  DB_PASSWORD: bXlzZWN1cmVwYXNz    # base64 dari "mysecurepass"
  API_KEY: YWJjMTIzeHl6            # base64 dari "abc123xyz"
  JWT_SECRET: bXlqd3RzZWNyZXQ=    # base64 dari "myjwtsecret"

# Encode base64
echo -n "mysecurepass" | base64
# Decode base64
echo "bXlzZWN1cmVwYXNz" | base64 -d

---
# Menggunakan Secret di Pod
apiVersion: v1
kind: Pod
metadata:
  name: app-pod
spec:
  containers:
    - name: app
      image: my-app:v1.0
      # Method 1: Env vars
      env:
        - name: DB_PASSWORD
          valueFrom:
            secretKeyRef:
              name: app-secrets
              key: DB_PASSWORD
        - name: API_KEY
          valueFrom:
            secretKeyRef:
              name: app-secrets
              key: API_KEY
      # Method 2: Mount sebagai file
      volumeMounts:
        - name: secrets-volume
          mountPath: /etc/secrets
          readOnly: true
  volumes:
    - name: secrets-volume
      secret:
        secretName: app-secrets

# hpa.yaml — Scale pod berdasarkan CPU utilization
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: web-app-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: web-app
  minReplicas: 2          # Minimum pod
  maxReplicas: 10         # Maximum pod
  metrics:
    # Scale jika CPU usage > 70%
    - type: Resource
      resource:
        name: cpu
        target:
          type: Utilization
          averageUtilization: 70
    # Scale jika Memory usage > 80%
    - type: Resource
      resource:
        name: memory
        target:
          type: Utilization
          averageUtilization: 80
  behavior:
    scaleUp:
      stabilizationWindowSeconds: 60
      policies:
        - type: Pods
          value: 2
          periodSeconds: 60
    scaleDown:
      stabilizationWindowSeconds: 300
      policies:
        - type: Pods
          value: 1
          periodSeconds: 120

# === MANUAL SCALING ===
kubectl scale deployment/web-app --replicas=5

# === HPA (Horizontal Pod Autoscaler) ===
# Buat HPA dari YAML
kubectl apply -f hpa.yaml

# Buat HPA imperatif
kubectl autoscale deployment web-app \
  --min=2 --max=10 --cpu-percent=70

# Lihat HPA
kubectl get hpa
kubectl describe hpa web-app-hpa

# Hapus HPA
kubectl delete hpa web-app-hpa

# === VPA (Vertical Pod Autoscaler) ===
# Mengubah resource request/limit secara otomatis
# (Memerlukan instalasi VPA terpisah)

# === Cluster Autoscaler ===
# Menambah/mengurangi node secara otomatis
# (Tersedia di cloud provider: EKS, GKE, AKS)