Azure를 위한 Kubernetes 개념

Kubernetes란?

클러스터 아키텍처: Control Plane 및 Node

# Kubernetes control plane components
# kube-apiserver    - REST API for all cluster operations
# etcd              - Distributed key-value store (cluster state)
# kube-scheduler    - Assigns pending pods to nodes
# kube-controller-manager  - Runs reconciliation controllers

# Worker node components
# kubelet           - Node agent, ensures containers run
# kube-proxy        - Network routing for services
# containerd        - Container runtime (runs containers)

Pod: 배포 가능한 가장 작은 단위

# Simple pod manifest
apiVersion: v1
kind: Pod
metadata:
  name: myapp-pod
  labels:
    app: myapp
spec:
  containers:
  - name: myapp
    image: mycontainerregistry.azurecr.io/myapp:v1.0
    ports:
    - containerPort: 80
    resources:
      requests:
        cpu: '100m'
        memory: '128Mi'
      limits:
        cpu: '500m'
        memory: '512Mi'

Deployment: Replica Set 관리

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1       # Create 1 extra pod during update
      maxUnavailable: 0 # Never reduce below desired count
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: mycontainerregistry.azurecr.io/myapp:v1.0
        ports:
        - containerPort: 80

Service: 안정적인 Network 엔드포인트

# Service exposing myapp pods externally
apiVersion: v1
kind: Service
metadata:
  name: myapp-svc
spec:
  type: LoadBalancer  # Creates Azure Load Balancer
  selector:
    app: myapp        # Routes traffic to pods with this label
  ports:
  - port: 80          # Service port
    targetPort: 80    # Pod/container port

# After creation, check the EXTERNAL-IP (Azure LB public IP)
# kubectl get service myapp-svc

다중 테넌시를 위한 Namespace

# Create a namespace for the dev team
kubectl create namespace dev-team

# Deploy into a specific namespace
kubectl apply -f deployment.yaml --namespace dev-team

# List all resources in a namespace
kubectl get all --namespace dev-team

# Set default namespace for current context
kubectl config set-context --current --namespace dev-team

ConfigMaps 및 Secrets

# Create a ConfigMap from literal values
kubectl create configmap app-config \
  --from-literal=APP_ENV=production \
  --from-literal=LOG_LEVEL=info

# Create a Secret
kubectl create secret generic db-secret \
  --from-literal=DB_PASSWORD='super-secret'

# Reference in a pod spec
# env:
# - name: APP_ENV
#   valueFrom:
#     configMapKeyRef:
#       name: app-config
#       key: APP_ENV
# - name: DB_PASSWORD
#   valueFrom:
#     secretKeyRef:
#       name: db-secret
#       key: DB_PASSWORD

Azure의 Persistent Volume

# PersistentVolumeClaim using Azure Disk
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-disk-pvc
spec:
  accessModes:
  - ReadWriteOnce   # Single-node read/write (Azure Disk)
  storageClassName: managed-csi
  resources:
    requests:
      storage: 10Gi

# Mount in a pod
# volumes:
# - name: data
#   persistentVolumeClaim:
#     claimName: my-disk-pvc
# volumeMounts:
# - name: data
#   mountPath: /data

Horizontal Pod Autoscaler

# Create an HPA targeting 50% CPU utilisation
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: myapp-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: myapp
  minReplicas: 2
  maxReplicas: 20
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 50

상태 확인: Liveness 및 Readiness Probe

livenessProbe:
  httpGet:
    path: /health
    port: 80
  initialDelaySeconds: 15
  periodSeconds: 20
  failureThreshold: 3

readinessProbe:
  httpGet:
    path: /ready
    port: 80
  initialDelaySeconds: 5
  periodSeconds: 10
  failureThreshold: 3

startupProbe:
  httpGet:
    path: /startup
    port: 80
  failureThreshold: 30
  periodSeconds: 10  # Allow 300s for slow startup

Resource 요청 및 제한

resources:
  requests:
    cpu: '250m'      # 0.25 CPU core guaranteed
    memory: '256Mi'  # 256 MiB guaranteed
  limits:
    cpu: '1'         # Max 1 CPU core
    memory: '512Mi'  # Max 512 MiB (OOMKilled if exceeded)

빠른 확인

lesson 요약