读写分离是借助MySQL中间件 ProxySQL 实现的
ProxySQL 有两个版本：官方版和percona版，percona版是基于官方版基础上修改C++语言开发，轻量级但性能优异(支持处理千亿级数据)具有中间件所需的绝大多数功能，包括：
- 多种方式的读/写分离
- 定制基于用户、基于schema、基于语句的规则对SQL语句进行路由
- 缓存查询结果
- 后端节点监控
准备
实现读写分离前，先实现主从复制
注意：slave节点需要设置read_only=1
| 主机 | IP地址 | 类型 |
|---|---|---|
| CentOS7.6 | 192.168.36.101 | Master |
| CentOS7.6 | 192.168.36.103 | Slave |
| CentOS7.6 | 192.168.36.104 | ProxySQL |
注：实验之前为保障实验顺利进行，请关闭主机的selinux以及防火墙服务
开始搭建
Master节点修改数据库配置文件
[root@Master ~]#cat /etc/my.cnf
[mysqld]
server_id=1 # 为Master节点设置一个全局唯一的ID号
binlog_format=row # 基于行复制的数据库语句
log-bin=/data/bin/mysql-bin # 启用二进制日志重新启动数据库服务
[root@Master ~]#service mysqld restart
Restarting mysqld (via systemctl): [ OK ]Master节点上创建带有复制权限的用户账号
MariaDB [(none)]> grant replication slave on *.* to repluser@'192.168.36.%' identified by 'centos';
Query OK, 0 rows affected (0.00 sec)查看Master的日志位置信息
MariaDB [mysql]> show master logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000001 | 912372 |
+------------------+-----------+
1 row in set (0.00 sec)Slave节点修改配置文件
[root@Slave-1 ~]#cat /etc/my.cnf
[mysqld]
server_id=2 # Slave节点设置全局唯一的ID号
read_only # 只读重新启动数据库服务
[root@Slave-1 ~]#systemctl restart mariadb使用Master创建的复制权限的用户账号进行同步
MariaDB [(none)]> CHANGE MASTER TO
-> MASTER_HOST='192.168.36.101',
-> MASTER_USER='repluser',
-> MASTER_PASSWORD='centos',
-> MASTER_PORT=3306,
-> MASTER_LOG_FILE='mysql-bin.000001',
-> MASTER_LOG_POS=245;
Query OK, 0 rows affected (0.01 sec)启动Slave线程
MariaDB [(none)]> slave start;
Query OK, 0 rows affected (0.00 sec)查看线程是否启动
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.36.101
Master_User: repluser
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 7389
Relay_Log_File: mariadb-relay-bin.000002
Relay_Log_Pos: 7673
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes # 从节点的IO线程
Slave_SQL_Running: Yes # 从节点的SQL线程
....
Seconds_Behind_Master: 0 # Master与SLave服务器差别延迟
.....
Master_Server_Id: 1
1 row in set (0.00 sec)检查数据同步情况
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| hellodb |
| mysql |
| performance_schema |
| test |
+--------------------+
5 rows in set (0.00 sec)配置ProxySQL的YUM仓库
[root@ProxySQL ~]#cat <<EOF | tee /etc/yum.repos.d/proxysql.repo
> [proxysql_repo]
> name= ProxySQL YUM repository
> baseurl=http://repo.proxysql.com/ProxySQL/proxysql-1.4.x/centos/\$releasever
> gpgcheck=1
> gpgkey=http://repo.proxysql.com/ProxySQL/repo_pub_key
> EOF
[proxysql_repo]
name= ProxySQL YUM repository
baseurl=http://repo.proxysql.com/ProxySQL/proxysql-1.4.x/centos/$releasever
gpgcheck=1
gpgkey=http://repo.proxysql.com/ProxySQL/repo_pub_key安装ProxySQL
[root@ProxySQL ~]#yum install -y proxysql mariadb启动ProxySQL
[root@ProxySQL ~]#rpm -ql proxysql
/etc/init.d/proxysql
...
由于proxysql启动脚本在init.d文件中，所以需要使用service启动
[root@ProxySQL ~]#service proxysql start
Starting ProxySQL: 2019-05-08 17:58:16 [INFO] Using config file /etc/proxysql.cnf
DONE!端口查看
[root@ProxySQL ~]#netstat -at
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:mysql 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:6032 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:6033 0.0.0.0:* LISTEN
# 6033端口是接收远程用户的连接、6032端口是连接，管理接口连接proxysql管理接口
[root@ProxySQL ~]#mysql -uadmin -padmin -P6032 -h227.0.0.1
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.5.30 (ProxySQL Admin Module)
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MySQL [(none)]>ProxySQL相当于小型的MySQL,自带：用户名admin、密码admin
添加主从节点的地址
# 添加Master节点
MySQL [(none)]> insert into mysql_servers(hostgroup_id,hostname,port) values(10,'192.168.36.101',3306);
Query OK, 1 row affected (0.00 sec)
# 添加Slave节点
MySQL [(none)]> insert into mysql_servers(hostgroup_id,hostname,port) values(10,'192.168.36.103',3306);
Query OK, 1 row affected (0.00 sec)
# 查看添加信息
MySQL [(none)]> select *from mysql_servers;
+--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 10 | 192.168.36.101 | 3306 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | |
| 10 | 192.168.36.103 | 3306 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | |
+--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
2 rows in set (0.00 sec)在Master上创建ProxySQL管理的账号
MariaDB [(none)]> grant replication client on *.* to monitor@'192.168.36.%' identified by 'magedu';
Query OK, 0 rows affected (0.00 sec)ProxySQL配置监控的用户名和密码设置，使其自动连接主从节点进行调整
MySQL [(none)]> set mysql-monitor_username='monitor';
Query OK, 1 row affected (0.00 sec)
MySQL [(none)]> set mysql-monitor_password='magedu';
Query OK, 1 row affected (0.00 sec)使配置加载到内存中生效，并保存到磁盘中
MySQL [(none)]> load mysql variables to runtime;
Query OK, 0 rows affected (0.00 sec)
MySQL [(none)]> save mysql variables to disk;
Query OK, 97 rows affected (0.01 sec)查看监控连接是否正常
MySQL [(none)]> select *from mysql_server_connect_log;
+----------------+------+------------------+-------------------------+-------------------------------------------------------------------------+
| hostname | port | time_start_us | connect_success_time_us | connect_error |
+----------------+------+------------------+-------------------------+-------------------------------------------------------------------------+
| 192.168.36.101 | 3306 | 1557312316296707 | 0 | Access denied for user 'monitor'@'192.168.36.104' (using password: YES) |
| 192.168.36.101 | 3306 | 1557312557263893 | 0 | Access denied for user 'monitor'@'192.168.36.104' (using password: YES) |
| 192.168.36.101 | 3306 | 1557312616308042 | 0 | Access denied for user 'monitor'@'192.168.36.104' (using password: YES) |
| 192.168.36.103 | 3306 | 1557312617121004 | 0 | Access denied for user 'monitor'@'192.168.36.104' (using password: YES) |
| 192.168.36.103 | 3306 | 1557312676308396 | 0 | Access denied for user 'monitor'@'192.168.36.104' (using password: YES) |
| 192.168.36.101 | 3306 | 1557312676936371 | 0 | Access denied for user 'monitor'@'192.168.36.104' (using password: YES) |
| 192.168.36.101 | 3306 | 1557312694163848 | 2228 | NULL |
| 192.168.36.103 | 3306 | 1557312695077512 | 4613 | NULL |
| 192.168.36.103 | 3306 | 1557312754164398 | 1370 | NULL |
| 192.168.36.103 | 3306 | 1557312874168899 | 2204 | NULL |
| 192.168.36.101 | 3306 | 1557312874890981 | 2939 | NULL |
+----------------+------+------------------+-------------------------+-------------------------------------------------------------------------+
22 rows in set (0.00 sec)设置分组信息
MySQL [(none)]> insert into mysql_replication_hostgroups values(10,20,"test");
Query OK, 1 row affected (0.00 sec)查看读写组信息
MySQL [(none)]> select *from mysql_replication_hostgroups;
+------------------+------------------+---------+
| writer_hostgroup | reader_hostgroup | comment |
+------------------+------------------+---------+
| 10 | 20 | test |
+------------------+------------------+---------+
1 row in set (0.00 sec)配置生效并保存到磁盘
MySQL [(none)]> save mysql servers to disk;
Query OK, 0 rows affected (0.02 sec)查看信息
MySQL [(none)]> select *from mysql_servers;
+--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 10 | 192.168.36.101 | 3306 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | |
| 20 | 192.168.36.103 | 3306 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | |
+--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
2 rows in set (0.00 sec)在master上进行创建设置账户，让客户端连接中间的调度器
MariaDB [(none)]> grant all on *.* to sqluser@'192.168.36.%' identified by 'magedu';
Query OK, 0 rows affected (0.00 sec)ProxySQL添加记录，将用户添加到mysql_users表中
MySQL [(none)]> insert into mysql_users(username,password,default_hostgroup) values('sqluser','magedu',10);
Query OK, 1 row affected (0.00 sec)查看是否添加成功
MySQL [(none)]> select *from mysql_users;
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+
| username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections|
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+
| sqluser | magedu | 1 | 0 | 10 | NULL | 0 | 1 | 0 | 1 | 1 | 10000|
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+
1 row in set (0.00 sec)保存配置
MySQL [(none)]> load mysql users to runtime;
Query OK, 0 rows affected (0.00 sec)
MySQL [(none)]> save mysql users to disk;
Query OK, 0 rows affected (0.01 sec)启用一个客户端连接ProxySQL进行测试
[root@CentOS6 ~]# mysql -usqluser -pmagedu -h292.168.36.104 -P6033
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.5.30 (ProxySQL)
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>查看连接到哪个主机
mysql> select @@server_id;
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
1 row in set (0.00 sec)ProxySQL上定义调度规则
MySQL [(none)]> insert into mysql_query_rules
-> (rule_id,active,match_digest,destination_hostgroup,apply) values
-> (1,1,'^select.*from update$',10,1),(2,1,'^select',20,1);
Query OK, 2 rows affected (0.00 sec)生效并存盘
MySQL [(none)]> load mysql query rules to runtime;
Query OK, 0 rows affected (0.00 sec)
MySQL [(none)]> save mysql query rules to disk;
Query OK, 0 rows affected (0.01 sec)客户端进行读写分离测试
[root@CentOS6 ~]# mysql -usqluser -pmagedu -h292.168.36.104 -P6033 -e 'select @@server_id;'
+-------------+
| @@server_id |
+-------------+
| 2 |
+-------------+
[root@CentOS6 ~]# mysql -usqluser -pmagedu -h292.168.36.104 -P6033 -e 'begin;use db1;insert t1 values(1);select @@server_id;'
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
