认识下 Kubernetes

┌─────────────────────────────────────────────────────────────┐
│                   控制平面 (Control Plane)                   │
│  ┌─────────────┐  ┌──────────┐  ┌─────────────┐  ┌────────┐ │
│  │  API Server │  │  etcd    │  │  Scheduler  │  │Controller││
│  │             │  │          │  │             │  │ Manager ││
│  └─────────────┘  └──────────┘  └─────────────┘  └────────┘ │
└─────────────────────────────────────────────────────────────┘
                            │
                            ▼
┌─────────────────────────────────────────────────────────────┐
│                   工作节点 (Worker Nodes)                    │
│  ┌─────────────┐  ┌──────────┐  ┌─────────────┐             │
│  │   kubelet   │  │ kube-proxy│  │ 容器运行时  │             │
│  │             │  │          │  │ (Docker等)  │             │
│  └─────────────┘  └──────────┘  └─────────────┘             │
│  ┌───────────────────────────────────────────────────────┐  │
│  │                      Pod (容器组)                     │  │
│  │  ┌──────────────┐  ┌──────────────┐                   │  │
│  │  │   容器1      │  │   容器2      │                   │  │
│  │  │  (应用)      │  │  (边车等)    │                   │  │
│  │  └──────────────┘  └──────────────┘                   │  │
│  └───────────────────────────────────────────────────────┘  │
└─────────────────────────────────────────────────────────────┘

# 安装 kubectl (Kubernetes 命令行工具)
# macOS
brew install kubectl

# Ubuntu
sudo apt-get update && sudo apt-get install -y kubectl

# 查看集群信息
kubectl cluster-info

# 查看节点状态
kubectl get nodes

# 创建一个 Deployment
kubectl create deployment nginx-deployment --image=nginx:1.19

# 查看 Deployment
kubectl get deployments

# 查看 Pod
kubectl get pods

# 创建 Service 暴露应用
kubectl expose deployment nginx-deployment --port=80 --type=NodePort

# 查看 Service
kubectl get services

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.19
        ports:
        - containerPort: 80

kubectl apply -f nginx-deployment.yaml
kubectl get pods

# 查看资源
kubectl get pods
kubectl get services
kubectl get deployments

# 查看详细信息
kubectl describe pod <pod-name>
kubectl describe service <service-name>

# 查看日志
kubectl logs <pod-name>

# 进入容器
kubectl exec -it <pod-name> -- /bin/bash

# 扩展 Deployment
kubectl scale deployment nginx-deployment --replicas=5

# 更新镜像
kubectl set image deployment/nginx-deployment nginx=nginx:1.20

# 回滚更新
kubectl rollout undo deployment/nginx-deployment

# 删除资源
kubectl delete deployment nginx-deployment
kubectl delete service nginx-service

apiVersion: v1
kind: Pod
metadata:
  name: multi-container-pod
spec:
  containers:
  - name: nginx
    image: nginx:1.19
    ports:
    - containerPort: 80
  - name: busybox
    image: busybox
    command: ['sh', '-c', 'while true; do echo "Hello Kubernetes!"; sleep 5; done']

# Deployment
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web-app
  template:
    metadata:
      labels:
        app: web-app
    spec:
      containers:
      - name: web-app
        image: nginx:1.19
        ports:
        - containerPort: 80
        env:
        - name: ENVIRONMENT
          value: "production"
---
# Service
apiVersion: v1
kind: Service
metadata:
  name: web-app-service
spec:
  selector:
    app: web-app
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: LoadBalancer

# ConfigMap 示例
apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
data:
  database_url: "mysql://localhost:3306"
  log_level: "INFO"

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi