我們首先看一下自己的環境：
MHA已經搭建：
master：172.16.16.35:3306 slave：172.16.16.35:3307 slave：172.16.16.34:3307
MHA manager在172.16.16.34，配置文件如下：
[root@localhost bin]# cat /etc/masterha/app1.cnf [server default] manager_log=/var/log/mha/app1/manager.log manager_workdir=/var/log/mha/app1.log master_binlog_dir=/home/mysql/db3306/log/ master_ip_failover_script=/usr/local/bin/master_ip_failover master_ip_online_change_script=/usr/local/bin/master_ip_online_change password=123456 ping_interval=1 remote_workdir=/tmp repl_password=123456 repl_user=root report_script=/usr/local/bin/send_report shutdown_script="" ssh_user=root user=root [server1] hostname=172.16.16.35 port=3306 [server2] candidate_master=1 check_repl_delay=0 hostname=172.16.16.34 port=3306 [server3] hostname=172.16.16.35 port=3307
下面我們基於這樣一套MHA環境搭建讀寫分離。
1：安裝ProxySQL軟件，這個我們部署到172.16.16.34上
[root@localhost bin]# sudo yum install http://www.percona.com/downloads/percona-release/redhat/0.1-4/percona-release-0.1-4.noarch.rpm [root@localhost bin]# yum install proxysql
最后有以下提示：
Installed: proxysql.x86_64 0:1.3.7-1.1.el6 Complete!
也就是安裝完成了。然后查一下具體的文件：
[root@localhost bin]# find / -name proxysql /var/lib/proxysql /var/run/proxysql /etc/rc.d/init.d/proxysql /usr/bin/proxysql
發現確實已經將ProxySQL安裝成功了
2：啟動配置ProxySQL
看一下配置文件：
[root@localhost bin]# cat /etc/proxysql-admin.cnf # proxysql admin interface credentials. export PROXYSQL_USERNAME="admin" export PROXYSQL_PASSWORD="admin" export PROXYSQL_HOSTNAME="localhost" export PROXYSQL_PORT="6032" # PXC admin credentials for connecting to pxc-cluster-node. export CLUSTER_USERNAME="admin" export CLUSTER_PASSWORD="admin" export CLUSTER_HOSTNAME="localhost" export CLUSTER_PORT="3306" # proxysql monitoring user. proxysql admin script will create this user in pxc to monitor pxc-nodes. export MONITOR_USERNAME="monitor" export MONITOR_PASSWORD="monit0r" # Application user to connect to pxc-node through proxysql export CLUSTER_APP_USERNAME="proxysql_user" export CLUSTER_APP_PASSWORD="passw0rd" # ProxySQL read/write hostgroup export WRITE_HOSTGROUP_ID="10" export READ_HOSTGROUP_ID="11" # ProxySQL read/write configuration mode. export MODE="singlewrite"
啟動：
[root@localhost bin]# proxysql-admin --config-file=/etc/proxysql-admin.cnf --enable This script will assist with configuring ProxySQL (currently only Percona XtraDB cluster in combination with ProxySQL is supported) ProxySQL read/write configuration mode is singlewrite ProxySQL is not running; please start the proxysql service
現在來說ProxySQL 的路由已經啟動，提示我們要啟動proxysql service
[root@localhost bin]# service proxy proxy proxysql proxysql-admin proxysql_galera_checker proxysql_node_monitor [root@localhost bin]# service proxysql start Starting ProxySQL: DONE! [root@localhost bin]# mysql -uadmin -padmin -h127.0.0.1 -P6032 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1 Server version: 5.7.14 (ProxySQL Admin Module) Copyright (c) 2000, 2016, 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>
可以看到我們已經登錄成功了，這里要說明的是 proxysql的默認配置文件是在：
[root@localhost bin]# find / -name proxysql.cnf
/etc/proxysql.cnf
接下來我們開始配置ProxySQL：
[root@localhost bin]# mysql -uadmin -padmin -h127.0.0.1 -P6032 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 2 Server version: 5.7.14 (ProxySQL Admin Module) Copyright (c) 2000, 2016, 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> show databases; +-----+---------+-------------------------------+ | seq | name | file | +-----+---------+-------------------------------+ | 0 | main | | | 2 | disk | /var/lib/proxysql/proxysql.db | | 3 | stats | | | 4 | monitor | | +-----+---------+-------------------------------+ 4 rows in set (0.00 sec) mysql> use admin Database changed mysql> show tables; +--------------------------------------+ | tables | +--------------------------------------+ | global_variables | | mysql_collations | | mysql_query_rules | | mysql_replication_hostgroups | | mysql_servers | | mysql_users | | runtime_global_variables | | runtime_mysql_query_rules | | runtime_mysql_replication_hostgroups | | runtime_mysql_servers | | runtime_mysql_users | | runtime_scheduler | | scheduler | +--------------------------------------+ 13 rows in set (0.00 sec)
下面加入主從信息：
mysql> insert into mysql_servers(hostgroup_id,hostname,port,weight,max_connections,max_replication_lag,comment) values(100,'172.16.16.35',3306,1,1000,10,'test'); Query OK, 1 row affected (0.00 sec) mysql> insert into mysql_servers(hostgroup_id,hostname,port,weight,max_connections,max_replication_lag,comment) values(101,'172.16.16.34',3306,1,1000,10,'test'); Query OK, 1 row affected (0.00 sec) mysql> insert into mysql_servers(hostgroup_id,hostname,port,weight,max_connections,max_replication_lag,comment) values(101,'172.16.16.35',3307,1,1000,10,'test'); Query OK, 1 row affected (0.00 sec) mysql> select * from mysql_servers; +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 100 | 172.16.16.35 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | test | | 101 | 172.16.16.34 | 3306 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | test | | 101 | 172.16.16.35 | 3307 | ONLINE | 1 | 0 | 1000 | 10 | 0 | 0 | test | +--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 3 rows in set (0.00 sec)
然后添加讀寫映射（主要是MHA后端切換的時候保證ProxySQL也能夠自動切換）：
mysql> insert into mysql_replication_hostgroups values(100,101,'masterha') ; Query OK, 1 row affected (0.00 sec) mysql> select * from mysql_replication_hostgroups; +------------------+------------------+----------+ | writer_hostgroup | reader_hostgroup | comment | +------------------+------------------+----------+ | 100 | 101 | masterha | +------------------+------------------+----------+ 1 row in set (0.00 sec)
為ProxySQL添加監控賬號：
mysql> GRANT SUPER, REPLICATION CLIENT ON *.* TO 'proxysql'@'172.16.16.%' IDENTIFIED BY 'proxysql'; Query OK, 0 rows affected, 1 warning (0.09 sec) mysql> flush privileges; Query OK, 0 rows affected (0.10 sec)
配置監控賬號（在proxySQL當中進行配置）：
mysql> set mysql-monitor_username='proxysql'; Query OK, 1 row affected (0.00 sec) mysql> set mysql-monitor_password='proxysql'; Query OK, 1 row affected (0.00 sec) mysql> load mysql variables to runtime; Query OK, 0 rows affected (0.00 sec) mysql> save mysql variables to disk; Query OK, 74 rows affected (0.02 sec)
PS:有時候runtime_mysql_servers的status不為ONLINE狀態的話可以通過查看monitor.mysql_server_ping_log這個表來查看具體的報錯信息。
mysql> select * from monitor.mysql_server_ping_log;
然后配置程序賬號，簡單點統一使用root：123456最高權限來配置：
mysql> insert into mysql_users(username,password,active,default_hostgroup,transaction_persistent) values('root','123456',1,100,1); Query OK, 1 row affected (0.00 sec) mysql> select * from mysql_users; +----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+ | username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections | +----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+ | root | 123456 | 1 | 0 | 100 | NULL | 0 | 1 | 0 | 1 | 1 | 10000 | +----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+ 1 row in set (0.00 sec)
配置完成以后開始重新加載和保存我們的配置：
mysql> load mysql servers to runtime; Query OK, 0 rows affected (0.01 sec) mysql> save mysql servers to disk; Query OK, 0 rows affected (0.08 sec) mysql> load mysql users to runtime; Query OK, 0 rows affected (0.00 sec) mysql> save mysql users to disk; Query OK, 0 rows affected (0.03 sec)
接下來開始配置路由規則：
mysql> INSERT INTO mysql_query_rules(active,match_pattern,destination_hostgroup,apply) VALUES(1,'^SELECT.*FOR UPDATE$',100,1); Query OK, 1 row affected (0.01 sec) mysql> INSERT INTO mysql_query_rules(active,match_pattern,destination_hostgroup,apply) VALUES(1,'^SELECT',101,1); Query OK, 1 row affected (0.00 sec) mysql> LOAD MYSQL QUERY RULES TO RUNTIME; Query OK, 0 rows affected (0.00 sec) mysql> SAVE MYSQL QUERY RULES TO DISK; Query OK, 0 rows affected (0.04 sec)
至此配置已經完成了
3：測試讀寫分離
在172.16.16.35上鏈接proxySQL端口6033，並且做簡單的select操作：
[root@localhost ~]# mysql -uroot -p123456 -h172.16.16.34 -P6033 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 22 Server version: 5.7.14 (ProxySQL) Copyright (c) 2000, 2016, 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> select * from maxiangqian.test; +-----+------+ | id | name | +-----+------+ | 1 | qq | | 2 | qq | | 4 | aa | | 11 | a | | 111 | a | +-----+------+ 5 rows in set (0.04 sec)
然后在進行查詢看一下：
mysql> select * from stats_mysql_query_digest;
可以看到已經完成了讀寫分離了。
mysql> select @@server_id; +-------------+ | @@server_id | +-------------+ | 353307 | +-------------+ 1 row in set (0.01 sec)
查看一下server ID已經路由到了172.16.16.35:3307這個從庫上了。
測一下for update：
mysql> select * from maxiangqian.test for update; +-----+------+ | id | name | +-----+------+ | 1 | qq | | 2 | qq | | 4 | aa | | 11 | a | | 111 | a | +-----+------+ 5 rows in set (0.00 sec)
再查看
mysql> select * from stats_mysql_query_digest;
已經自動路由到了主庫。
至此ProxySQL+MySQL MHA讀寫分離測試完成。。。未完待續
5：關於ProxySQL的思考以及簡單的命令
ProxySQL通過以上方式是可以實現讀寫分離，但是這種方式真的就沒有問題了嗎，如果是一些比如查詢訂單狀態的這種要求實時性非常高的SQL的話，似乎被路由到了從庫就會出現BUG。我們可以選擇在程序端控制這些參數，ProxySQL只作為一個負載均衡來使用，給ProxySQL創建多個賬號，一個讀寫，一個只讀。然后程序去實現讀寫分離。
ProxySQL是分三層來設計運行的，分別為RUNTIME ，MEMORY ，DISK ：
RUNTIME 代表的是ProxySQL當前生效的配置，包括 global_variables, mysql_servers, mysql_users, mysql_query_rules。無法直接修改這里的配置，必須要從下一層load進來。
MEMORY 是平時在mysql命令行修改的 main 里頭配置，可以認為是SQLite數據庫在內存的鏡像
DISK / CONFIG FILE 持久存儲的那份配置，一般在$(DATADIR)/proxysql.db，在重啟的時候會從硬盤里加載。 /etc/proxysql.cnf文件只在第一次初始化的時候用到，完了后，如果要修改監聽端口，還是需要在管理命令行里修改，再 save 到硬盤
常用命令：
LOAD MYSQL SERVERS TO RUNTIME -- 讓修改的配置生效，也就是從MEMORY 把參數LOAD過來，等價於LOAD MYSQL USERS FROM MEMORY，這個語句的語法比較單間，FROM代表從上層LOAD過來，TO代表從本層到某一個層。比如前面我們設置了MySQL的監控賬號，但是還是要執行LOAD和SAVE保存變量並且使變量生效。