Mysql数据库高可用群集最佳实践

# 临时关闭SELinux
setenforce 0
# 永久关闭SELinux
sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config
# 关闭防火墙
systemctl stop firewalld
systemctl disable firewalld

yum install -y wget vim net-tools ntpdate
# 同步系统时间
ntpdate time.aliyun.com
echo "*/5 * * * * /usr/sbin/ntpdate time.aliyun.com" >> /var/spool/cron/root

# 下载MySQL YUM源
wget https://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpm
yum localinstall -y mysql80-community-release-el7-3.noarch.rpm
yum install -y mysql-community-server
# 启动MySQL并设置开机自启
systemctl start mysqld
systemctl enable mysqld

# 获取初始密码
grep "temporary password" /var/log/mysqld.log
# 登录MySQL修改密码
mysql -uroot -p
ALTER USER 'root'@'localhost' IDENTIFIED BY 'Pwd@123456';
FLUSH PRIVILEGES;

[mysqld]
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data
socket=/usr/local/mysql/data/mysql.sock
port=3306
bind-address=0.0.0.0
skip-name-resolve
# 主从复制核心配置
log-bin=/usr/local/mysql/data/mysql-bin
binlog_format=MIXED
server-id=1  # 两台节点ID必须不同，Master2设置为2
auto-increment-increment=2
auto-increment-offset=1
# 性能优化（适配2G内存）
innodb_buffer_pool_size=512M
max_connections=100
character-set-server=utf8
default-storage-engine=INNODB

systemctl restart mysqld

-- 创建复制用户，允许指定IP连接
CREATE USER 'repl'@'192.168.10.%' IDENTIFIED BY '123456';
-- 授予复制权限
GRANT REPLICATION SLAVE ON *.* TO 'repl'@'192.168.10.%';
-- 刷新权限
FLUSH PRIVILEGES;

SHOW MASTER STATUS;

CHANGE MASTER TO
MASTER_HOST='192.168.10.101',
MASTER_USER='repl',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000001',  -- 替换为Master1的Binlog文件名
MASTER_LOG_POS=156;  -- 替换为Master1的Binlog位置
-- 启动从节点复制
START SLAVE;
-- 查看复制状态，确保Slave_IO_Running和Slave_SQL_Running都为Yes
SHOW SLAVE STATUS\G

CHANGE MASTER TO
MASTER_HOST='192.168.10.102',
MASTER_USER='repl',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000001',  -- 替换为Master2的Binlog文件名
MASTER_LOG_POS=156;  -- 替换为Master2的Binlog位置
START SLAVE;
SHOW SLAVE STATUS\G

CREATE DATABASE testdb;
USE testdb;
CREATE TABLE t1(id INT,name VARCHAR(20));
INSERT INTO t1 VALUES(1,'master1');

SELECT * FROM testdb.t1;

yum install -y haproxy
systemctl enable haproxy

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

defaults
    mode        tcp
    log         global
    option      tcplog
    option      dontlognull
    retries     3
    timeout     connect 5s
    timeout     client 1m
    timeout     server 1m
    timeout     check 5s
    maxconn     3000

# MySQL负载均衡配置
listen mysql
    bind 0.0.0.0:3306  # 监听所有IP的3306端口
    mode tcp
    balance leastconn  # 最少连接算法，分发请求到负载最低的节点
    server mysql1 192.168.10.101:3306 check port 3306 maxconn 300
    server mysql2 192.168.10.102:3306 check port 3306 maxconn 300

# 检查配置文件语法
haproxy -c -f /etc/haproxy/haproxy.cfg
# 启动服务
systemctl start haproxy
# 查看3306端口是否监听
netstat -tulnp | grep 3306

mysql -utest -p123456 -h192.168.10.103 -P3306

yum install -y keepalived
systemctl enable keepalived

global_defs {
    router_id r1  # 节点标识，两台节点不同
}

# 检测HAProxy状态的脚本
vrrp_script chk_haproxy {
    script "/etc/keepalived/chk.sh"
    interval 2  # 每2秒检测一次
}

vrrp_instance VI_1 {
    state BACKUP  # 两台节点都配置为BACKUP，避免抢占
    nopreempt     # 关闭抢占模式，故障恢复后不抢回VIP
    interface ens33  # 绑定的网卡，根据实际修改
    virtual_router_id 51  # 虚拟路由ID，两台节点必须相同
    priority 100  # 优先级，103节点优先级设为100，104设为99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111  # 认证密码，两台节点必须相同
    }
    virtual_ipaddress {
        192.168.10.100/24  # 虚拟IP
    }
    track_script {
        chk_haproxy  # 关联HAProxy检测脚本
    }
    notify_backup "/etc/init.d/haproxy restart"
    notify_fault "/etc/init.d/haproxy stop"
}

router_id r2
priority 99
其余配置与103节点保持一致

#!/bin/bash
# 检测HAProxy进程是否存在
if [ $(ps -C haproxy --no-header | wc -l) -eq 0 ]; then
    # 若进程不存在，停止Keepalived，触发VIP切换
    systemctl stop keepalived
fi

chmod +x /etc/keepalived/chk.sh

# 启动服务
systemctl start keepalived
# 查看虚拟IP是否绑定成功（103节点）
ip a