1.MaxScale 是干什么的？
MaxScale是maridb开发的一个mysql数据中间件，其配置简单，能够实现读写分离，并且可以根据主从状态实现写库的自动切换，对多个从服务器能实现负载均衡。
2.MaxScale 实验环境
|------|----------------|------------------|
| 中间件 | 192.168.183.51 | MaxScale 22.08.4 |
| 主服务器 | 192.168.183.11 | mysql 8.0.30 |
| 从服务器 | 192.168.183.12 | mysql 8.0.30 |
| 从服务器 | 192.168.183.13 | mysql 8.0.30 |
3.实现数据库主从复制
主库配置：：
# 主库配置
# tail -3 /etc/my.cnf.d/mysql-server.cnf
server_id=11
gtid_mode=ON
enforce-gtid-consistency=ON
# systemctl restart mysqld
--创建用户
create user 'rep'@'192.168.183.%' identified with mysql_native_password by '123456';
--用户授权 "同步复制"、"同步复制状态"
grant replication slave on *.* to 'rep'@'192.168.183.%';
从库配置：
--从库配置
# tail -3 /etc/my.cnf.d/mysql-server.cnf
server_id=12/13
gtid_mode=ON
enforce-gtid-consistency=ON
read_only=ON
# systemctl restart mysqld
--配置主从同步
CHANGE MASTER TO
MASTER_HOST = '192.168.183.11',
MASTER_USER = 'rep',
MASTER_PASSWORD = '123456',
MASTER_AUTO_POSITION = 1;
--启动主从同步
start slave
--检查
# mysql -e 'show slave status \G' | grep -E -w "Slave_IO_Running|Slave_SQL_Running"
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
4.创建用户
在开始配置之前，需要在 master中为 MaxScale 创建两个用户，用于监控模块和路由模块，已经实现主从复制的前提下，主库创建的用户，能同步到从库上
1) 创建监控用户
--创建用户
create user 'maxscale_monitor'@'192.168.183.%' identified with mysql_native_password by 'Admin@123456';
--用户授权 "同步复制"、"同步复制状态"
grant replication slave, replication client on *.* to maxscale_monitor@'192.168.183.%';
2) 创建路由用户
--创建用户
create user 'maxscale_route'@'192.168.183.%' identified with mysql_native_password by 'Admin@123456';
--用户授权
GRANT SHOW DATABASES ON *.* TO maxscale_route@'192.168.183.%';
GRANT SELECT ON mysql.user TO maxscale_route@'192.168.183.%';
GRANT SELECT ON mysql.db TO maxscale_route@'192.168.183.%';
GRANT SELECT ON mysql.tables_priv TO maxscale_route@'192.168.183.%';
GRANT SELECT ON mysql.columns_priv TO maxscale_route@'192.168.183.%';
GRANT SELECT ON mysql.proxies_priv TO maxscale_route@'192.168.183.%';
5.安装MaxScale
1、在 Download MariaDB Products & Tools | MariaDB 选择对应系统合适的版本下载安装
这里使用下载mariadb仓库源的方式：
curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | sudo bash
2、下载 maxscale
dnf install maxscale -y
3、配置 maxscale
在/etc/maxscale.cnf.d新建一个配置my.cnf或者直接修改/etc/maxscale.cnf文件
[root@Rocky ~]# cat /etc/maxscale.cnf
[maxscale]
threads=auto
admin_host=0.0.0.0
admin_secure_gui=false
[dbserv1]
type=server
address=192.168.183.11
port=3306
protocol=MariaDBBackend
[dbserv2]
type=server
address=192.168.183.12
port=3306
protocol=MariaDBBackend
[dbserv3]
type=server
address=192.168.183.13
port=3306
protocol=MariaDBBackend
[MySQL-Monitor]
type=monitor
module=mariadbmon
servers=dbserv1, dbserv2, dbserv3
user=maxscale_monitor
password=Admin@123456
monitor_interval=2s
[Read-Write-Service]
type=service
router=readwritesplit
servers=dbserv1,dbserv2,dbserv3
user=maxscale_route
password=Admin@123456
enable_root_user=true
[Read-Write-Listener]
type=listener
service=Read-Write-Service
protocol=MariaDBClient
address=0.0.0.0
port=3306
6.启动服务并查看运行状态
[root@Rocky ~]# maxscale -f /etc/maxscale.cnf.d/my.cnf -U maxscale
使用 maxctrl list servers 命令查看运行状态
查看注册服务
使用 maxctrl list listeners Read-Write-Service 命令查看服务监听状态信息
7.客户端连接测试
创建登录用户create user 'admin_user'@'%' identified with mysql_native_password by 'Admin@123456'; 并授予登陆用户权限：grant all privileges on *.* to 'admin_user'@'%' with grant option;
任意一台salve进行登陆：ip为Maxscale地址，用户和密码为master