k8s 部署 mysql 高可用 示例

k8s 部署 mysql 高可用示例可以采用主从复制和集群方式。

1. 主从复制方式

在 k8s 中采用 StatefulSet 进行部署，首先需要创建一个 ConfigMap，用于存放 MySQL 的配置文件。示例：

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql-config
data:
  my.cnf: |
    [mysqld]
    server-id=1
    log-bin=mysql-bin
    binlog-do-db=testdb
    binlog-ignore-db=mysql
    relay-log=mysqld-relay-bin
    relay-log-index=mysqld-relay-bin.index

然后创建一个 PersistentVolumeClaim（PVC）用于存储数据，示例：

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

创建一个主节点的 StatefulSet，示例：

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql-master
spec:
  serviceName: mysql
  replicas: 1
  selector:
    matchLabels:
      app: mysql
      role: master
  template:
    metadata:
      labels:
        app: mysql
        role: master
    spec:
      containers:
      - name: mysql
        image: mysql:5.7
        ports:
        - containerPort: 3306
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: "root"
        volumeMounts:
        - name: mysql-data
          mountPath: /var/lib/mysql
        - name: mysql-config
          mountPath: /etc/mysql/conf.d
      volumes:
      - name: mysql-data
        persistentVolumeClaim:
          claimName: mysql-data
      - name: mysql-config
        configMap:
          name: mysql-config

创建一个从节点的 StatefulSet，示例：

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql-slave
spec:
  serviceName: mysql
  replicas: 2
  selector:
    matchLabels:
      app: mysql
      role: slave
  template:
    metadata:
      labels:
        app: mysql
        role: slave
    spec:
      containers:
      - name: mysql
        image: mysql:5.7
        ports:
        - containerPort: 3306
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: "root"
        - name: MYSQL_MASTER_SERVICE_HOST
          value: mysql-master
        - name: MYSQL_MASTER_SERVICE_PORT
          value: "3306"
        volumeMounts:
        - name: mysql-data
          mountPath: /var/lib/mysql
        - name: mysql-config
          mountPath: /etc/mysql/conf.d
      volumes:
      - name: mysql-data
        persistentVolumeClaim:
          claimName: mysql-data
      - name: mysql-config
        configMap:
          name: mysql-config

2. 集群方式

在 k8s 中采用 StatefulSet 进行部署，首先需要创建一个 ConfigMap，用于存放 MySQL 的配置文件。示例：

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql-config
data:
  my.cnf: |
    [mysqld]
    server-id=1
    log-bin=mysql-bin
    binlog-do-db=testdb
    binlog-ignore-db=mysql
    relay-log=mysqld-relay-bin
    relay-log-index=mysqld-relay-bin.index
    skip-name-resolve
    bind-address=0.0.0.0

然后创建一个 PersistentVolumeClaim（PVC）用于存储数据，示例：

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

创建一个 StatefulSet，示例：

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
spec:
  serviceName: mysql
  replicas: 3
  selector:
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - name: mysql
        image: mysql:5.7
        ports:
        - containerPort: 3306
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: "root"
        volumeMounts:
        - name: mysql-data
          mountPath: /var/lib/mysql
        - name: mysql-config
          mountPath: /etc/mysql/conf.d
      volumes:
      - name: mysql-data
        persistentVolumeClaim:
          claimName: mysql-data
      - name: mysql-config
        configMap:
          name: mysql-config

在 Kubernetes 中可以使用 StatefulSet 对于 MySQL 的集群进行管理，StatefulSet 可以保证 Pod 的唯一性，同时也可以保证 Pod 的有序性。在集群中，每个 Pod 会有一个唯一的 hostname，在 StatefulSet 中我们可以使用 hostname 来访问不同的 Pod。例如：mysql-0、mysql-1、mysql-2。在 MySQL 中，我们需要配置 GTID（Global Transaction Identifier）来保证所有节点的数据都是同步的。创建一个 ConfigMap，用于存放 GTID 相关的配置文件。示例：

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql-gtid-config
data:
  init.sql: |
    SET @@GLOBAL.GTID_PURGED='';
    CREATE USER repluser@'%' IDENTIFIED BY 'password';
    GRANT REPLICATION SLAVE ON *.* TO 'repluser'@'%';
    FLUSH PRIVILEGES;

然后在 StatefulSet 中添加一个容器用于初始化集群，示例：

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
spec:
  serviceName: mysql
  replicas: 3
  selector:
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - name: mysql
        image: mysql:5.7
        ports:
        - containerPort: 3306
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: "root"
        volumeMounts:
        - name: mysql-data
          mountPath: /var/lib/mysql
        - name: mysql-config
          mountPath: /etc/mysql/conf.d
      - name: init-mysql
        image: mysql:5.7
        command: ["/bin/bash", "-c", "while ! mysqladmin ping -h mysql-0 --silent; do sleep 1; done; mysql -h mysql-0 -uroot -proot -e \"$(cat /etc/mysql/init.sql)\""]
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: "root"
        volumeMounts:
        - name: mysql-gtid-config
          mountPath: /etc/mysql
      volumes:
      - name: mysql-data
        persistentVolumeClaim:
          claimName: mysql-data
      - name: mysql-config
        configMap:
          name: mysql-config
      - name: mysql-gtid-config
        configMap:
          name: mysql-gtid-config

这样就完成了 k8s 部署 mysql 高可用的示例。