讀寫分離是藉助MySQL中間件 ProxySQL 實現的
ProxySQL 有兩個版本：官方版和percona版，percona版是基於官方版基礎上修改C++語言開發，輕量級但性能優異(支持處理千億級數據)具有中間件所需的絕大多數功能，包括：
- 多種方式的讀/寫分離
- 定製基於用戶、基於schema、基於語句的規則對SQL語句進行路由
- 緩存查詢結果
- 後端節點監控
準備
實現讀寫分離前，先實現主從複製
注意：slave節點需要設置read_only=1
| 主機 | IP地址 | 類型 |
|---|---|---|
| CentOS7.6 | 192.168.36.101 | Master |
| CentOS7.6 | 192.168.36.103 | Slave |
| CentOS7.6 | 192.168.36.104 | ProxySQL |
注：實驗之前爲保障實驗順利進行，請關閉主機的selinux以及防火牆服務
開始搭建
Master節點修改數據庫配置文件
[root@Master ~]#cat /etc/my.cnf
[mysqld]
server_id=1 # 爲Master節點設置一個全局唯一的ID號
binlog_format=row # 基於行復制的數據庫語句
log-bin=/data/bin/mysql-bin # 啓用二進制日誌重新啓動數據庫服務
[root@Master ~]#service mysqld restart
Restarting mysqld (via systemctl): [ OK ]Master節點上創建帶有複製權限的用戶賬號
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的日誌位置信息
MariaDB [mysql]> show master logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000001 | 912372 |
+------------------+-----------+
1 row in set (0.00 sec)Slave節點修改配置文件
[root@Slave-1 ~]#cat /etc/my.cnf
[mysqld]
server_id=2 # Slave節點設置全局唯一的ID號
read_only # 只讀重新啓動數據庫服務
[root@Slave-1 ~]#systemctl restart mariadb使用Master創建的複製權限的用戶賬號進行同步
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)啓動Slave線程
MariaDB [(none)]> slave start;
Query OK, 0 rows affected (0.00 sec)查看線程是否啓動
*************************** 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 # 從節點的IO線程
Slave_SQL_Running: Yes # 從節點的SQL線程
....
Seconds_Behind_Master: 0 # Master與SLave服務器差別延遲
.....
Master_Server_Id: 1
1 row in set (0.00 sec)檢查數據同步情況
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| hellodb |
| mysql |
| performance_schema |
| test |
+--------------------+
5 rows in set (0.00 sec)配置ProxySQL的YUM倉庫
[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安裝ProxySQL
[root@ProxySQL ~]#yum install -y proxysql mariadb啓動ProxySQL
[root@ProxySQL ~]#rpm -ql proxysql
/etc/init.d/proxysql
...
由於proxysql啓動腳本在init.d文件中，所以需要使用service啓動
[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端口是接收遠程用戶的連接、6032端口是連接，管理接口連接proxysql管理接口
[root@ProxySQL ~]#mysql -uadmin -padmin -P6032 -h127.0.0.1
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相當於小型的MySQL,自帶：用戶名admin、密碼admin
添加主從節點的地址
# 添加Master節點
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節點
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上創建ProxySQL管理的賬號
MariaDB [(none)]> grant replication client on *.* to monitor@'192.168.36.%' identified by 'magedu';
Query OK, 0 rows affected (0.00 sec)ProxySQL配置監控的用戶名和密碼設置，使其自動連接主從節點進行調整
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)使配置加載到內存中生效，並保存到磁盤中
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)查看監控連接是否正常
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)設置分組信息
MySQL [(none)]> insert into mysql_replication_hostgroups values(10,20,"test");
Query OK, 1 row affected (0.00 sec)查看讀寫組信息
MySQL [(none)]> select *from mysql_replication_hostgroups;
+------------------+------------------+---------+
| writer_hostgroup | reader_hostgroup | comment |
+------------------+------------------+---------+
| 10 | 20 | test |
+------------------+------------------+---------+
1 row in set (0.00 sec)配置生效並保存到磁盤
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上進行創建設置賬戶，讓客戶端連接中間的調度器
MariaDB [(none)]> grant all on *.* to sqluser@'192.168.36.%' identified by 'magedu';
Query OK, 0 rows affected (0.00 sec)ProxySQL添加記錄，將用戶添加到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)啓用一個客戶端連接ProxySQL進行測試
[root@CentOS6 ~]# mysql -usqluser -pmagedu -h192.168.36.104 -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>查看連接到哪個主機
mysql> select @@server_id;
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+
1 row in set (0.00 sec)ProxySQL上定義調度規則
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)生效並存盤
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)客戶端進行讀寫分離測試
[root@CentOS6 ~]# mysql -usqluser -pmagedu -h192.168.36.104 -P6033 -e 'select @@server_id;'
+-------------+
| @@server_id |
+-------------+
| 2 |
+-------------+
[root@CentOS6 ~]# mysql -usqluser -pmagedu -h192.168.36.104 -P6033 -e 'begin;use db1;insert t1 values(1);select @@server_id;'
+-------------+
| @@server_id |
+-------------+
| 1 |
+-------------+