基于Kubernetes部署MySQL主从集群

以下是一个基于Kubernetes部署MySQL主从集群的详细YAML示例，包含StatefulSet、Service、ConfigMap和Secret等关键配置。MySQL主从集群需要至少1个主节点和多个从节点，这里使用 StatefulSet + 初始化脚本 实现主从自动配置。

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1. 创建 Namespace (可选)

apiVersion: v1
kind: Namespace
metadata:name: mysql-cluster

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2. 创建 Secret (存储MySQL密码)

apiVersion: v1
kind: Secret
metadata:name: mysql-secretsnamespace: mysql-cluster
type: Opaque
data:root-password: eHg=  # echo -n "xx" | base64 (示例密码)replication-password: eHg=  # 主从同步专用密码

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3. 创建 ConfigMap (主从配置文件)

apiVersion: v1
kind: ConfigMap
metadata:name: mysql-confignamespace: mysql-cluster
data:master.cnf: |[mysqld]log-bin=mysql-binserver-id=1slave.cnf: |[mysqld]log-bin=mysql-binserver-id=2init.sql: |  # 初始化主从复制的SQL脚本CREATE USER 'repl'@'%' IDENTIFIED BY 'xx';  # 密码需与Secret中一致GRANT REPLICATION SLAVE ON *.* TO 'repl'@'%';FLUSH PRIVILEGES;

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4. 创建 Service (主从分离访问)

# 主节点服务
apiVersion: v1
kind: Service
metadata:name: mysql-masternamespace: mysql-cluster
spec:ports:- name: mysqlport: 3306selector:app: mysqlrole: masterclusterIP: None# 从节点服务
apiVersion: v1
kind: Service
metadata:name: mysql-slavenamespace: mysql-cluster
spec:ports:- name: mysqlport: 3306selector:app: mysqlrole: slaveclusterIP: None

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5. 创建 StatefulSet (1主2从)

apiVersion: apps/v1
kind: StatefulSet
metadata:name: mysqlnamespace: mysql-cluster
spec:serviceName: mysqlreplicas: 3selector:matchLabels:app: mysqltemplate:metadata:labels:app: mysqlrole: slave  # 默认标记为slave，init容器中将修改第一个Pod为masterspec:initContainers:- name: init-mysqlimage: mysql:8.0command:- bash- "-c"- |# 根据Pod序号分配server-id和角色[[ `hostname` =~ -([0-9]+)$ ]] || exit 1ordinal=${BASH_REMATCH[1]}if [[ $ordinal -eq 0 ]]; then# 主节点配置cp /mnt/config/master.cnf /mnt/conf.d/echo "role=master" > /mnt/conf.d/roleelse# 从节点配置cp /mnt/config/slave.cnf /mnt/conf.d/echo "role=slave" > /mnt/conf.d/rolefivolumeMounts:- name: confmountPath: /mnt/conf.d- name: config-mapmountPath: /mnt/config- name: clone-mysqlimage: alpine:3.18command:- bash- "-c"- |# 只有从节点需要等待主节点初始化完成if [ -f /mnt/conf.d/role ] && grep -q "slave" /mnt/conf.d/role; thenuntil nslookup mysql-0.mysql; dosleep 2donefivolumeMounts:- name: confmountPath: /mnt/conf.dcontainers:- name: mysqlimage: mysql:8.0env:- name: MYSQL_ROOT_PASSWORDvalueFrom:secretKeyRef:name: mysql-secretskey: root-password- name: MYSQL_REPL_PASSWORDvalueFrom:secretKeyRef:name: mysql-secretskey: replication-passwordports:- name: mysqlcontainerPort: 3306volumeMounts:- name: datamountPath: /var/lib/mysql- name: confmountPath: /etc/mysql/conf.d- name: init-sqlmountPath: /docker-entrypoint-initdb.dlivenessProbe:exec:command: ["mysqladmin", "ping", "-uroot", "-p${MYSQL_ROOT_PASSWORD}"]initialDelaySeconds: 30periodSeconds: 10readinessProbe:exec:command: ["mysql", "-uroot", "-p${MYSQL_ROOT_PASSWORD}", "-e", "SELECT 1"]initialDelaySeconds: 5periodSeconds: 5volumes:- name: confemptyDir: {}- name: config-mapconfigMap:name: mysql-configitems:- key: master.cnfpath: master.cnf- key: slave.cnfpath: slave.cnf- name: init-sqlconfigMap:name: mysql-configitems:- key: init.sqlpath: init.sqlvolumeClaimTemplates:- metadata:name: dataspec:accessModes: ["ReadWriteOnce"]storageClassName: "standard"  # 根据环境调整resources:requests:storage: 10Gi

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6. 主从初始化自动化脚本 (StatefulSet启动后执行)

主节点启动后自动创建复制用户，从节点自动连接主节点：

# 在StatefulSet的Pod模板中添加以下生命周期钩子
lifecycle:postStart:exec:command:- "/bin/bash"- "-c"- |if [ -f /etc/mysql/conf.d/role ] && grep -q "master" /etc/mysql/conf.d/role; then# 主节点执行初始化SQLmysql -uroot -p${MYSQL_ROOT_PASSWORD} < /docker-entrypoint-initdb.d/init.sqlelse# 从节点配置主从复制until mysql -h mysql-0.mysql -uroot -p${MYSQL_ROOT_PASSWORD} -e "SELECT 1"; dosleep 1donemysql -uroot -p${MYSQL_ROOT_PASSWORD} -e "CHANGE MASTER TOMASTER_HOST='mysql-0.mysql',MASTER_USER='repl',MASTER_PASSWORD='${MYSQL_REPL_PASSWORD}',MASTER_AUTO_POSITION=1;START SLAVE;"fi

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验证主从同步

# 检查主节点状态
kubectl exec -it mysql-0 -n mysql-cluster -- mysql -uroot -p -e "SHOW MASTER STATUS\G"# 检查从节点同步状态
kubectl exec -it mysql-1 -n mysql-cluster -- mysql -uroot -p -e "SHOW SLAVE STATUS\G"

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关键注意事项：

1. 主节点高可用：此方案主节点单点，若需高可用，需结合 Orchestrator 或 ProxySQL 实现故障转移。
2. 数据持久化：确保 storageClassName 与实际存储系统匹配（如 rook-cephfs、nfs）。
3. 密码安全：通过Secret管理敏感信息，禁止明文存储。
4. 网络通信：确保StatefulSet的Pod之间可通过DNS名称互相访问（如 mysql-0.mysql.mysql-cluster.svc.cluster.local）。
5. 扩展性：通过增加 replicas 数量扩展从节点。

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完整架构示意图：

Client -> Service(mysql-master) -> Pod(mysql-0) [Master]
Client -> Service(mysql-slave)  -> Pod(mysql-1, mysql-2) [Slave]

可根据需求调整副本数量或增加读写分离中间件（如ProxySQL）。