MySQL 高可用 - 技术栈

架构

组件	作用	核心优势
MySQL 主主复制	两台 MySQL 互为主从，双向同步数据	数据冗余、无单点、支持读写分离
HAProxy	数据库负载均衡、健康检查、连接管理	读写分发、自动剔除异常节点
Keepalived	提供 VIP、故障漂移、HAProxy 高可用	秒级切换、对业务透明

整体访问链路

复制代码

客户端 → VIP(Keepalived) → HAProxy → MySQL Master1/Master2

环境

节点	IP	角色
Master1	192.168.1.101	MySQL 主、HAProxy、Keepalived 主
Master2	192.168.1.102	MySQL 主、HAProxy、Keepalived 备
VIP	192.168.1.200	对外统一入口

前置要求

关闭防火墙 / 开放 3306、8080、VRRP 端口
关闭 SELinux 或设为 Permissive
时间同步（NTP）
两台 MySQL 版本一致

MySQL 双主复制

1. Mater1 my.cnf 配置

ini 复制代码

[mysqld]
server-id               = 101
log-bin                 = mysql-bin
binlog-format           = ROW
auto-increment-increment= 2
auto-increment-offset   = 1
relay-log               = mysql-relay-bin
log-slave-updates       = 1
sync-binlog             = 1
innodb_flush_log_at_trx_commit = 1

2. Master2 my.cnf

ini 复制代码

[mysqld]
server-id               = 102
log-bin                 = mysql-bin
binlog-format           = ROW
auto-increment-increment= 2
auto-increment-offset   = 2
relay-log               = mysql-relay-bin
log-slave-updates       = 1
sync-binlog             = 1
innodb_flush_log_at_trx_commit = 1

3. 创建复制账号（两台都执行）

sql 复制代码

CREATE USER 'repl'@'192.168.1.%' IDENTIFIED BY 'Repl@123';
GRANT REPLICATION SLAVE ON *.* TO 'repl'@'192.168.1.%';
FLUSH PRIVILEGES;

4. 建立双向复制

节点 1 执行 show master status; 记录 File & Position

节点 2 执行：

sql 复制代码

change master to
master_host='192.168.1.101',
master_user='repl',
master_password='Repl@123',
master_log_file='mysql-bin.000001',
master_log_pos=154;

start slave;
show master status;

反向配置节点 1 指向节点 2，完成主主

HAProxy 配置

1. 安装

bash 复制代码

yum -y install haproxy

2. haproxy.cfg

vim /etc/haproxy/haproxy.cfg

ini 复制代码

global
    log 127.0.0.1 local2
    chroot /var/lib/haproxy
    pidfile /var/run/haproxy.pid
    user haproxy
    group haproxy
    daemon
    maxconn 4000

defaults
	# MySQL使用四层代理
    mode tcp
    log global
    option tcplog
    retries 3
    timeout connect 5s
    timeout client 50s
    timeout server 50s

listen mysql-read-write
	# 监听
    bind 0.0.0.0:3306
    mode tcp
    balance roundrobin
    option mysql-check user haproxy_check
    # 配置MySQL服务
    server mysql1 192.168.1.101:3306 check weight 1
    server mysql2 192.168.1.102:3306 check weight 1

listen stats
    bind 0.0.0.0:8080
    mode http
    stats enable
    stats uri /haproxy-stats
    stats auth admin:admin

3. MySQL 健康检查用户

sql 复制代码

CREATE USER 'haproxy_check'@'%' IDENTIFIED BY '';
FLUSH PRIVILEGES;

4. 启动

bash 复制代码

systemctl start haproxy
systemctl enable haproxy

Keepalived 配置

1. 安装

bash 复制代码

yum install -y keepalived

2. MySQL 检测脚本

bash 复制代码

#!/bin/bash
MYSQL_USER="haproxy_check"
MYSQL_HOST="localhost"
MYSQL_PORT="3306"

mysql -u$MYSQL_USER -h$MYSQL_HOST -P$MYSQL_PORT -e "SELECT 1" >/dev/null 2>&1
if [ $? -ne 0 ]; then
    systemctl stop haproxy
    exit 1
fi
exit 0

bash 复制代码

chmod +x /usr/local/bin/check_mysql.sh

3. Mater1 keepalived.conf

ini 复制代码

global_defs {
    router_id mysql_ha_master
}

vrrp_script check_mysql {
    script "/usr/local/bin/check_mysql.sh"
    interval 2
    weight -20
    fall 3
    rise 2
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.200/24
    }
    track_script {
        check_mysql
    }
}

4. Master2 keepalived.conf

ini 复制代码

global_defs {
    router_id mysql_ha_backup
}

vrrp_script check_mysql {
    script "/usr/local/bin/check_mysql.sh"
    interval 2
    weight -20
    fall 3
    rise 2
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.200/24
    }
    track_script {
        check_mysql
    }
}

5. 启动

bash 复制代码

systemctl start keepalived
systemctl enable keepalived