在K8S集群中构建复杂的MySQL单实例数据库

文档说明

实验环境：kubernetes Version v1.9.6
网络CNI：fannel
存储CSI: NFS Dynamic Class

前期准备

利用NFS动态提供Kubernetes后端存储卷[https://jimmysong.io/kubernetes-handbook/practice/using-nfs-for-persistent-storage.html]

简单部署 （无法满足生产环境要求）

一、持久化存储卷pvc
mysql-claim.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-claim
  annotations:
    volume.beta.kubernetes.io/storage-class: "default" 
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

二、敏感数据Secret （最好base64编码加密）
mysql-dev-secret.yaml

apiVersion: v1
kind: Secret
metadata:
  name: mysql-dev-secret
type: Opaque
data:
  MYSQL_ROOT_PASSWORD: devadmin
  MYSQL_DATABASE: test

三、Deployment
mysql-deployment.yaml

apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: mysql
  namespace: default
  labels:
    k8s-app: mysql
spec:
  replicas: 1
  selector: 
    matchLabels:
      k8s-app: mysql
  template:
    metadata:
      labels:
        k8s-app: mysql
    spec:
      containers:
      - image: mysql:5.7
        name: mysql
        imagePullPolicy: Always
        envFrom:
        - secretRef:
            name: mysql-dev-secret
        ports:
        - containerPort: 3306
          name: mysql
        volumeMounts:
        - name: nfs-pv
          mountPath: /var/lib/mysql
      volumes:
        - name: nfs-pv
          persistentVolumeClaim:
            claimName: mysql-claim

四、Service

• 1无clusterIP (kubernetes内部通过clusterIP访问)

apiVersion: v1
kind: Service
metadata:
  name: mysql
spec:
  ports:
    - port: 3306
  selector:
    k8s-app: mysql
  clusterIP: None      

• 2 NodePort （通过NodePort暴露给集群外部访问，可以搭配外部LoadBalancer提供服务）

apiVersion: v1
kind: Service
metadata:
  name: mysql
spec:
  selector:
    k8s-app: mysql
  ports:
  - nodePort: 33006
    protocol: TCP
    port: 3306
    targetPort: 3306
  type: NodePort

验证：

PVC

PVC.png

Secret

Secret.png

Deployment

Deployment.png

Service

Service.png

扩展部署（可用于生产环境）

一、持久化存储卷pvc (pv 详见前期准备nfs提供动态pv部分)

tips: 确保存储卷后端的文件夹内为空，不然后期重新启动，会报错

mysql-ex-claim.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-ex-claim
  annotations:
    volume.beta.kubernetes.io/storage-class: "default" #根据实际情况调整
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 2Gi  #根据实际情况调整

二、敏感数据secret
mysql-secret.yaml

apiVersion: v1
kind: Secret
metadata:
  name: mysql-user-pwd
data:
  mysql-root-pwd: aGFyZHRvZ3Vlc3M=
  mysql-app-user-pwd: aGFyZHRvZ3Vlc3M=
  mysql-test-user-pwd: aGFyZHRvZ3Vlc3M= 

image.png

三、ConfigMap用户自定义配置
mysql-cm.yaml （mysql8.0配置）

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql-config
data:
  custom.cnf: |
        [mysqld]
        default_storage_engine=innodb
        skip_external_locking
        lower_case_table_names=1
        skip_host_cache
        skip_name_resolve

mysql-cm.yaml （mysql5.7配置）

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql-config
data:
  custom.cnf: |
        [mysqld]
        server-id=1
        log-bin
        expire_logs_days=7
        sync_binlog=0
        binlog_cache_size=1M

四、Deployment (包含初始化容器、健康检查)

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    app: mysql-ex
  name: mysql-ex
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mysql-ex
  template:
     metadata:
       labels:
         app: mysql-ex
     spec:
       initContainers:
       - name: mysql-init
         image: busybox
         imagePullPolicy: IfNotPresent
         env:
         - name: MYSQL_TEST_USER_PASSWORD
           valueFrom:
             secretKeyRef:
               name: mysql-user-pwd
               key: mysql-test-user-pwd
         command:
           - sh
           - "-c"
           - |
             set -ex
             rm -rf /var/lib/mysql/lost+found
             cat > /docker-entrypoint-initdb.d/mysql-testdb-initt.sql < /docker-entrypoint-initdb.d/mysql-appdb-init.sql <

五、Service
NodePort形式

apiVersion: v1
kind: Service
metadata:
  name: mysql-ex
spec:
  selector:
    app: mysql-ex
  ports:
  - nodePort: 33016
    protocol: TCP
    port: 3306
    targetPort: 3306
  type: NodePort

tips: 以上默认使用的image用的latest是mysql8.0 configmap有变化

验证:

image.png

image.png

数据库连接情况：

image.png

image.png

参考文档：
https://segmentfault.com/a/1190000014966962