Linux学习-基于CentOS7的ProxySQL实现读写分离
Posted hovin
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一、实验环境
主机：3台，一台ProxySQL(192.168.214.37)，两台主从复制，master(192.168.214.17)，slave(192.168.214.27)
系统：CentOS7.6
数据库：mariadb-server-5.5.60（光盘yum源）
ProxySQL：proxysql-1.4.16
ProxySQL组成
服务脚本：/etc/init.d/proxysql
配置文件：/etc/proxysql.cnf
主程序：/usr/bin/proxysql
基于SQLITE的数据库文件：/var/lib/proxysql/
启动ProxySQL：service proxysql start启动后会监听两个默认端口
6032：ProxySQL的管理端口
6033：ProxySQL对外提供服务的端口
二、相关步骤
1、实现读写分离前，先实现主从复制，即master(192.168.214.17)，slave(192.168.214.27)实现主从复制，实现方法可参照：https://www.cnblogs.com/hovin/p/11990677.html
2、安装ProxySQL，在192.168.214.37这台主机上操作，安装方法有
基于RPM下载安装：https://github.com/sysown/proxysql/releases
基于YUM仓库安装：
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/\\$releasevergpgcheck=1
gpgkey=http://repo.proxysql.com/ProxySQL/repo_pub_key
EOF
[root@centos7-37 ~]# yum install -y proxysql
3、使用mysql客户端连接到ProxySQL的管理接口6032，默认管理员用户和密码都是admin
[root@centos7-37 ~]# 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)]> show databases; +-----+---------------+-------------------------------------+ | seq | name | file | +-----+---------------+-------------------------------------+ | 0 | main | | | 2 | disk | /var/lib/proxysql/proxysql.db | | 3 | stats | | | 4 | monitor | | | 5 | stats_history | /var/lib/proxysql/proxysql_stats.db | +-----+---------------+-------------------------------------+ 5 rows in set (0.00 sec)
数据库说明:
main 是默认的”数据库”名，表里存放后端db实例、用户验证、路由规则等信息。表名以 runtime_开头的表示proxysql当前运行的配置内容，不能通过dml语句修改，只能修改对应的不以 runtime_ 开头的(在内存)里的表，然后 LOAD 使其生效，SAVE 使其存到硬盘以供下次重启加载；
disk 是持久化到硬盘的配置，sqlite数据文件
stats 是proxysql运行抓取的统计信息，包括到后端各命令的执行次数、流量、processlist、查询种类汇总/执行时间等等
monitor 库存储 monitor 模块收集的信息，主要是对后端db的健康/延迟检查
说明:
在main和monitor数据库中的表， runtime_开头的是运行时的配置，不能修改，只能修改非 runtime_ 表
修改后必须执行LOAD ... TO RUNTIME才能加载到RUNTIME生效
执行save ... to disk 才将配置持久化保存到磁盘，即保存在proxysql.db文件中global_variables 有许多变量可以设置，其中就包括监听的端口、管理账号等
4、向ProxySQL中添加MySQL节点，以下操作不需要 use main 也可成功
MySQL [(none)]> show tables; #显示表 +--------------------------------------------+ | tables | +--------------------------------------------+ | global_variables | | mysql_collations | | mysql_group_replication_hostgroups | | mysql_query_rules | | mysql_query_rules_fast_routing | | mysql_replication_hostgroups | | mysql_servers | | mysql_users | | proxysql_servers | | runtime_checksums_values | | runtime_global_variables | | runtime_mysql_group_replication_hostgroups | | runtime_mysql_query_rules | | runtime_mysql_query_rules_fast_routing | | runtime_mysql_replication_hostgroups | | runtime_mysql_servers | | runtime_mysql_users | | runtime_proxysql_servers | | runtime_scheduler | | scheduler | +--------------------------------------------+ 20 rows in set (0.00 sec) MySQL [(none)]> select * from sqlite_master where name=\'mysql_servers\'\\G; *************************** 1. row *************************** type: table name: mysql_servers tbl_name: mysql_servers rootpage: 2 sql: CREATE TABLE mysql_servers (hostgroup_id INT CHECK (hostgroup_id>=0) NOT NULL DEFAULT 0 , hostname VARCHAR NOT NULL , port INT NOT NULL DEFAULT 3306 , status VARCHAR CHECK (UPPER(status) IN (\'ONLINE\',\'SHUNNED\',\'OFFLINE_SOFT\', \'OFFLINE_HARD\')) NOT NULL DEFAULT \'ONLINE\' , weight INT CHECK (weight >= 0) NOT NULL DEFAULT 1 , compression INT CHECK (compression >=0 AND compression <= 102400) NOT NULL DEFAULT 0 , max_connections INT CHECK (max_connections >=0) NOT NULL DEFAULT 1000 , max_replication_lag INT CHECK (max_replication_lag >= 0 AND max_replication_lag <= 126144000) NOT NULL DEFAULT 0 , use_ssl INT CHECK (use_ssl IN(0,1)) NOT NULL DEFAULT 0 , max_latency_ms INT UNSIGNED CHECK (max_latency_ms>=0) NOT NULL DEFAULT 0 , comment VARCHAR NOT NULL DEFAULT \'\' , PRIMARY KEY (hostgroup_id, hostname, port) ) 1 row in set (0.00 sec) ERROR: No query specified MySQL [(none)]> select * from mysql_servers; #查询节点主机，目前没有 Empty set (0.00 sec) MySQL [(none)]> insert into mysql_servers(hostgroup_id,hostname,port) values(10,\'192.168.214.17\',3306); #添加主节点 Query OK, 1 row affected (0.00 sec) MySQL [(none)]> insert into mysql_servers(hostgroup_id,hostname,port) values(10,\'192.168.214.27\',3306); #添加从节点 Query OK, 1 row affected (0.00 sec) MySQL [(none)]> select * from mysql_servers; #再查询有了 +--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | hostgroup_id | hostname | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment | +--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ | 10 | 192.168.214.17 | 3306 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | | 10 | 192.168.214.27 | 3306 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | | +--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+ 2 rows in set (0.00 sec) MySQL [(none)]> load mysql servers to runtime; #添加后记得先加载 Query OK, 0 rows affected (0.00 sec) MySQL [(none)]> save mysql servers to disk; #再写入磁盘持久化保存 Query OK, 0 rows affected (0.01 sec)
5、添加监控后端节点的用户；ProxySQL通过每个节点的read_only值来自动调整它们是属于读组还是写组(因此主从配置时从节点配置文件中记得加read_only选项)
1). 在主节点master(192.168.214.17)上执行
MariaDB [(none)]> grant replication client on *.* to monitor@\'192.168.214.%\' identified by \'monitor\';
2). 在ProxySQL(192.168.214.37)上配置监控，同时记得加载到RUNTIME，并保存到disk
MySQL [(none)]> set mysql-monitor_username=\'monitor\';
MySQL [(none)]> set mysql-monitor_password=\'monitor\';
MySQL [(none)]> load mysql variables to runtime;
MySQL [(none)]> save mysql variables to disk;
监控模块的指标保存在monitor库的log表中，查看监控连接是否正常的 (对connect指标的监控):(如果connect_error的结果为NULL则表示正常)
MySQL [(none)]> select * from mysql_server_connect_log;
查看监控心跳信息 (对ping指标的监控)： MySQL [(none)]> select * from mysql_server_ping_log;
查看read_only和replication_lag的监控日志：
MySQL [(none)]> select * from mysql_server_read_only_log;
MySQL [(none)]> select * from mysql_server_replication_lag_log;
6、设置分组信息，需要修改的是main库中的mysql_replication_hostgroups表，该表有3个字段：writer_hostgroup，reader_hostgroup，comment, 指定写组的id为10，读组的id为20，记得将mysql_replication_hostgroups表的修改加载到RUNTIME生效，同时保存到磁盘
MySQL [(none)]> insert into mysql_replication_hostgroups values(10,20,"test"); Query OK, 1 row affected (0.00 sec) MySQL [(none)]> load mysql servers to runtime; Query OK, 0 rows affected (0.00 sec) MySQL [(none)]> save mysql servers to disk; Query OK, 0 rows affected (0.01 sec)
Monitor模块监控后端的read_only值，按照read_only的值将节点自动移动到读/写组
MySQL [(none)]> select hostgroup_id,hostname,port,status,weight from mysql_servers; +--------------+----------------+------+--------+--------+ | hostgroup_id | hostname | port | status | weight | +--------------+----------------+------+--------+--------+ | 10 | 192.168.214.17 | 3306 | ONLINE | 1 | | 20 | 192.168.214.27 | 3306 | ONLINE | 1 | +--------------+----------------+------+--------+--------+ 2 rows in set (0.00 sec)
7、配置发送SQL语句的用户，在主节点master(192.168.214.17)上创建访问用户
MariaDB [(none)]> grant all on *.* to sqluser@\'192.168.214.%\' identified by \'centos\'; Query OK, 0 rows affected (0.00 sec)
8、在ProxySQL(192.168.214.37)上配置，将用户sqluser添加到mysql_users表中，default_hostgroup默认组设置为写组10，当读写分离的路由规则不符合时，会访问默认组的数据库，同时加载到RUNTIME并保存磁盘
MySQL [(none)]> insert into mysql_users(username,password,default_hostgroup) values(\'sqluser\',\'centos\',10); Query OK, 1 row affected (0.00 sec) MySQL [(none)]> load mysql user to runtime; Query OK, 0 rows affected (0.00 sec) MySQL [(none)]> save mysql user to disk; Query OK, 0 rows affected (0.01 sec)
9、使用sqluser用户测试是否能路由到默认的10写组，实现读、写数据
[root@centos7-37 ~]# mysql -usqluser -pcentos -P6033 -h127.0.0.1 -e \'select @@server_id\' +-------------+ | @@server_id | +-------------+ | 17 | +-------------+ [root@centos7-37 ~]# mysql -usqluser -pcentos -P6033 -h127.0.0.1 -e \'create database testdb\' [root@centos7-37 ~]# mysql -usqluser -pcentos testdb -P6033 -h127.0.0.1 -e \'create table t(id int)\'
10、在proxysql(192.168.214.37)上配置路由规则，实现读写分离，与规则有关的表:mysql_query_rules和mysql_query_rules_fast_routing，后者是前者的扩展表，1.4.7之后支持；插入路由规则：将select语句分离到20的读组，select语句中有一个特殊语句SELECT...FOR UPDATE它会申请写锁，应路由到10的写组，插入后记得加载RUNTIME并保存到磁盘
MySQL [(none)]> insert into mysql_query_rules (rule_id,active,match_digest,destination_hostgroup,apply)VALUES (1,1,\'^SELECT.*FOR UPDATE$\',10,1),(2,1,\'^SELECT\',20,1); Query OK, 2 rows affected (0.00 sec) MySQL [(none)]> load mysql query rules to runtime; Query OK, 0 rows affected (0.00 sec) MySQL [(none)]> save mysql query rules to disk; Query OK, 0 rows affected (0.01 sec) MySQL [(none)]> select rule_id,active,match_digest,destination_hostgroup,apply from mysql_query_rules; +---------+--------+----------------------+-----------------------+-------+ | rule_id | active | match_digest | destination_hostgroup | apply | +---------+--------+----------------------+-----------------------+-------+ | 1 | 1 | ^SELECT.*FOR UPDATE$ | 10 | 1 | | 2 | 1 | ^SELECT | 20 | 1 | +---------+--------+----------------------+-----------------------+-------+ 2 rows in set (0.00 sec)
注意:因ProxySQL根据rule_id顺序进行规则匹配，select ... for update规则的rule_id必须要小于普通的select规则的rule_id
11、配置已完成，开始测试
1). 测试读操作是否路由给20的读组
[root@centos7-37 ~]# mysql -usqluser -pcentos -P6033 -h127.0.0.1 -e \'select @@server_id\' +-------------+ | @@server_id | +-------------+ | 17 | +-------------+
2). 测试写操作，以事务方式进行测试
[root@centos7-37 ~]# mysql -usqluser -pcentos -P6033 -h127.0.0.1 -e \'start transaction;select @@server_id;commit;select @@server_id\' +-------------+ | @@server_id | +-------------+ | 17 | +-------------+ +-------------+ | @@server_id | +-------------+ | 17 | +-------------+ [root@centos7-37 ~]# mysql -usqluser -pcentos -P6033 -h127.0.0.1 -e \'insert testdb.t values (1)\' [root@centos7-37 ~]# mysql -usqluser -pcentos -P6033 -h127.0.0.1 -e \'select id from testdb.t\' +------+ | id | +------+ | 1 | +------+
3). 路由的信息：查询stats库中的stats_mysql_query_digest表
MySQL [(none)]> SELECT hostgroup hg,sum_time, count_star, digest_text FROM stats_mysql_query_digest ORDER BY sum_time DESC; +----+----------+------------+----------------------------------+ | hg | sum_time | count_star | digest_text | +----+----------+------------+----------------------------------+ | 20 | 29138678 | 7 | select @@server_id | | 10 | 8747 | 1 | create table t(id int) | | 10 | 4310 | 1 | insert testdb.t values (?) | | 10 | 4170 | 2 | select @@server_id | | 10 | 1473 | 1 | start transaction | | 20 | 1392 | 1 | select id from testdb.t | | 10 | 795 | 1 | create database testdb | | 10 | 368 | 1 | commit | | 10 | 0 | 1 | select @@version_comment limit ? | | 10 | 0 | 11 | select @@version_comment limit ? | +----+----------+------------+----------------------------------+ 10 rows in set (0.00 sec)
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