K8S部署实战

• 部署 demo 应用
• 部署 MySQL
• 使用 ConfigMap 来配置 Redis

部署 demo 应用

部署 MySQL

• 官网例子

mysql-deployment.yaml

apiVersion: v1
kind: Service
metadata:
  name: mysql
spec:
  ports:
  - port: 3306
  selector:
    app: mysql
  clusterIP: None
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
spec:
  selector:
    matchLabels:
      app: mysql
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - image: mysql:5.6
        name: mysql
        env:
          # Use secret in real usage
        - name: MYSQL_ROOT_PASSWORD
          value: 123456
        ports:
        - containerPort: 3306
          name: mysql
        volumeMounts:
        - name: mysql-persistent-storage
          mountPath: /var/lib/mysql
      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim:
          claimName: mysql-pv-claim

mysql-pv.yaml

apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-pv-volume
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 20Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data"
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pv-claim
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 20Gi

# 部署 YAML 文件中定义的 PV 和 PVC：
kubectl apply -f https://k8s.io/examples/application/mysql/mysql-pv.yaml
# 部署 YAML 文件中定义的 Deployment：
kubectl apply -f https://k8s.io/examples/application/mysql/mysql-deployment.yaml
# 展示 Deployment 相关信息:
kubectl describe deployment mysql
# 列举出 Deployment 创建的 pods:
kubectl get pods -l app=mysql
# 查看 PersistentVolumeClaim：
kubectl describe pvc mysql-pv-claim
# 访问 MySQL 实例
kubectl run -it --rm --image=mysql:5.6 --restart=Never mysql-client -- mysql -h mysql -p123456
kubectl exec mysql-client -- mysql -h mysql -p123456
# 通过名称删除部署的对象
kubectl delete deployment,svc mysql
kubectl delete pvc mysql-pv-claim
kubectl delete pv mysql-pv-volume

使用 ConfigMap 来配置 Redis

• 官方例子
  redis-config

maxmemory 2mb
maxmemory-policy allkeys-lru

:::

redis-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: redis
spec:
  containers:
  - name: redis
    image: redis:5.0.4
    command:
      - redis-server
      - "/redis-master/redis.conf"
    env:
    - name: MASTER
      value: "true"
    ports:
    - containerPort: 6379
    resources:
      limits:
        cpu: "0.1"
    volumeMounts:
    - mountPath: /redis-master-data
      name: data
    - mountPath: /redis-master
      name: config
  volumes:
    - name: data
      emptyDir: {}
    - name: config
      configMap:
        name: example-redis-config
        items:
        - key: redis-config
          path: redis.conf

kustomization.yaml

configMapGenerator:
- name: example-redis-config
  files:
  - redis-config
resources:
- redis-pod.yaml

# 创建 ConfigMap 和 Pod 对象，再当前目录下执行
kubectl apply -k .
# 检查创建的对象
kubectl get -k .
# 使用 kubectl exec 进入 pod 并运行 redis-cli 工具来验证配置已正确应用：
kubectl exec -it redis -- redis-cli

127.0.0.1:6379> CONFIG GET maxmemory
1) "maxmemory"
2) "2097152"
127.0.0.1:6379> CONFIG GET maxmemory-policy
1) "maxmemory-policy"
2) "allkeys-lru"

# 删除创建的 pod
kubectl delete pod redis