keepalived识别MGR主节点

keepalived识别MGR主节点

一、前言

• Linux 发行版：CentOS-7-x86_64-DVD-1804.iso
• MySQL 版本：mysql80-community-release-el7-9 （version：8.0.34）

keepalived 官网：https://www.keepalived.org/

Group Replication：https://dev.mysql.com/doc/refman/8.0/en/group-replication.html

Single-Primary Mode：https://dev.mysql.com/doc/refman/8.0/en/group-replication-single-primary-mode.html

Multi-Primary Mode：https://dev.mysql.com/doc/refman/8.0/en/group-replication-multi-primary-mode.html

MySQL Yum Repository：https://dev.mysql.com/downloads/repo/yum/

[ContOS] MySQL安装部署：https://blog.csdn.net/u011424614/article/details/94555816

[Windows] MySQL安装部署：https://blog.csdn.net/u011424614/article/details/102466819

CentOS7安装部署MySQL80：https://blog.csdn.net/u011424614/article/details/132418916

CentOS7部署MySQL80集群：https://blog.csdn.net/u011424614/article/details/133222091

CentOS基础操作命令：https://blog.csdn.net/u011424614/article/details/94555916

二、正文

1.场景说明

• MGR单主模式下，通过 keepalived 识别 MGR 主节点，当主节点下线后，自动识别主节点，并切换到主节点
• 另外说明：MGR多主模式下，不需要识别主节点，确认健康状态，切换到任意一个主节点即可

2.硬件配置

机器名	IP	端口
sys-cluster-01	192.168.249.131	3306、33061
sys-cluster-02	192.168.249.132	3306、33061
sys-cluster-03	192.168.249.133	3306、33061

• 虚拟IP：192.168.249.130

3.安装部署MGR

在3 台服务器上启动MGR

• MGR单主模式安装参考：《CentOS7部署MySQL80集群》
• 目录：

1. 安装目录：/usr/local/mysql
2. 数据库文件目录，例如表结构和数据：/var/lib/mysql
3. 日志文件目录：/var/log/mysql
4. 配置文件目录：/etc/mysql
5. 用户名：root 密码：Root@#123456

4.部署Keepalived

1）安装Keepalived

• 3台服务器上，安装 Keepalived

# 创建安装目录
mkdir /opt/keepalived
cd /opt/keepalived

# 下载安装包
wget https://www.keepalived.org/software/keepalived-2.2.8.tar.gz --no-check-certificate
# 解压缩
tar -zxvf keepalived-2.2.8.tar.gz

cd keepalived-2.2.8/
# 安装依赖
yum -y install openssl-devel gcc-c++ libnl libnl-devel libnfnetlink-devel

# 安装 Keepalived
./configure --prefix=/opt/keepalived/ --sysconf=/etc

make && make install

3）检测脚本

• 3台服务器上，创建检测脚本

# 创建脚本目录
mkdir /opt/keepalived/script

# 编辑检测脚本
vim /opt/keepalived/script/check_mysql_primary.sh

• 配置检查脚本，根据实际情况，修改 MySQL 用户和密码

#!/bin/bash

# 设置 MySQL 连接参数
MYSQL_USER="root"
MYSQL_PASSWORD="Root@#123456"
MYSQL_DATABASE="performance_schema"

# 获取当前电脑的主机名和 IP 地址
HOSTNAME=$(hostname)
IP=$(hostname -I | awk '{print $1}')

# 查询 MySQL 中的主节点 host
PRIMARY_HOST=$(mysql -u$MYSQL_USER -p$MYSQL_PASSWORD -e "SELECT MEMBER_HOST FROM $MYSQL_DATABASE.replication_group_members WHERE MEMBER_ROLE='PRIMARY';" -s)

# 检查主机名和 IP 是否与主节点匹配
if [ "$HOSTNAME" == "$PRIMARY_HOST" ]; then
  exit 0
elif [ "$IP" == "$PRIMARY_HOST" ]; then
  exit 0
else
  exit 1
fi

• 设置文件的执行权限

chmod +x /opt/keepalived/script/check_mysql_primary.sh

4）MASTER节点配置

• 如下配置需要根据实际环境进行配置：

1. router_id：服务器标识

2. interface：网卡（终端执行命令：ifconfig ）

3. real_server：本机IP和端口

4. priority：master的优先级

5. unicast_src_ip 、unicast_peer：节点IP

• 192.168.249.131 配置文件

cat > /etc/keepalived/keepalived.conf <

5）BACKUP节点配置

• 192.168.249.132 配置文件

cat > /etc/keepalived/keepalived.conf <

• 192.168.249.133 配置文件

cat > /etc/keepalived/keepalived.conf <

6）Keepalived自启动

• 3台服务器上，配置 Keepalived 自启动

cat > /etc/systemd/system/keepalived.service <

• 重新加载服务的配置文件

systemctl daemon-reload

• 启动服务

systemctl start keepalived.service

• 查询服务状态

systemctl status keepalived.service

• master 启动成功提示

Keepalived_vrrp[80017]: (VI_1) Entering MASTER STATE

5常用命令

命令	功能
systemctl start keepalived.service	启动服务
systemctl enable keepalived.service	开机自启动
systemctl status keepalived.service	服务状态
systemctl restart keepalived.service	重启服务
systemctl stop keepalived.service	停止服务
systemctl daemon-reload	重新加载服务的配置文件