关系型数据库之mysql-proxy实现读写分离

简要:

mysql-proxy作为mysql测试项目，可以实现读写分离架构，具有开发能力的公司通过二次开发的方式去完善bug应用在生产环境中，下面我们通过案例使用mysql-proxy实现读写分离。

准备环境:

1.系统环境：Centos6.5
2.数据库版本：10.0.10-MariaDB-log MariaDB Server
3.Host:
Master主机: master.samlee.com 172.16.100.7
Slave主机: slave.samlee.com 172.16.100.8

Proxy主机:proxy.samlee.com 172.16.100.9

架构图如下:

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配置mysql-proxy服务器:

(1)安装部署mysql-proxy

# wget # tar xf mysql-proxy-0.8.4-linux-glibc2.3-x86-64bit.tar.gz -C /usr/local/# cd /usr/local/# ln -sv mysql-proxy-0.8.4-linux-glibc2.3-x86-64bit mysql-proxy

(2)创建代理用户以及修改程序目录权限

# useradd -s /sbin/nologin -r mysql-proxy# chown -R mysql-proxy.mysql-proxy /usr/local/mysql-proxy-0.8.4-linux-glibc2.3-x86-64bit/

(3)为mysql-proxy提供SysV服务脚本，内容如下所示：

# vim /etc/rc.d/init.d/mysql-proxy#!/bin/bash## mysql-proxy This script starts and stops the mysql-proxy daemon## chkconfig: - 78 30# processname: mysql-proxy# description: mysql-proxy is a proxy daemon for mysql# Source function library.. /etc/rc.d/init.d/functionsprog="/usr/local/mysql-proxy/bin/mysql-proxy"# Source networking configuration.if [ -f /etc/sysconfig/network ]; then    . /etc/sysconfig/networkfi# Check that networking is up.[ ${NETWORKING} = "no" ] && exit 0# Set default mysql-proxy configuration.ADMIN_USER="admin"ADMIN_PASSWD="admin"ADMIN_LUA_SCRIPT="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"PROXY_OPTIONS="--daemon"PROXY_PID=/var/run/mysql-proxy.pidPROXY_USER="mysql-proxy"# Source mysql-proxy configuration.if [ -f /etc/sysconfig/mysql-proxy ]; then    . /etc/sysconfig/mysql-proxyfiRETVAL=0start() {    echo -n $"Starting $prog: "    daemon $prog $PROXY_OPTIONS --pid-file=$PROXY_PID --proxy-address="$PROXY_ADDRESS" --user=$PROXY_USER --admin-username="$ADMIN_USER" --admin-lua-script="$ADMIN_LUA_SCRIPT" --admin-password="$ADMIN_PASSWORD"    RETVAL=$?    echo    if [ $RETVAL -eq 0 ]; then        touch /var/lock/subsys/mysql-proxy    fi}stop() {    echo -n $"Stopping $prog: "    killproc -p $PROXY_PID -d 3 $prog    RETVAL=$?    echo    if [ $RETVAL -eq 0 ]; then        rm -f /var/lock/subsys/mysql-proxy        rm -f $PROXY_PID    fi}# See how we were called.case "$1" in    start)        start        ;;    stop)        stop        ;;    restart)        stop        start        ;;    condrestart|try-restart)        if status -p $PROXY_PIDFILE $prog >&/dev/null; then            stop            start        fi        ;;    status)        status -p $PROXY_PID $prog        ;;    *)        echo "Usage: $0 {start|stop|restart|reload|status|condrestart|try-restart}"        RETVAL=1        ;;esacexit $RETVAL--授予执行权限，加入服务列表自启动# chmod +x /etc/rc.d/init.d/mysql-proxy# chkconfig --add mysql-proxy

(4)为服务脚本提供配置文件/etc/sysconfig/mysql-proxy，内容如下所示：

# vim /etc/sysconfig/mysql-proxy# Options for mysql-proxyADMIN_USER="admin"ADMIN_PASSWORD="admin"ADMIN_ADDRESS=""ADMIN_LUA_SCRIPT="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"PROXY_ADDRESS=""PROXY_USER="mysql-proxy"PROXY_OPTIONS="--daemon --log-level=info --log-use-syslog --plugins=proxy --plugins=admin --proxy-backend-addresses=172.16.100.7:3306 --proxy-read-only-backend-addresses=172.16.100.8:3306 --proxy-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua"最后一行运行选项，可以根据需要修改。         --proxy-backend-addresses=     --proxy--read-only-backend-addresses=     可以指定多次，从而指定多台服务器。          其他常用选项如下    mysql-proxy的配置选项大致可分为帮助选项、管理选项、代理选项及应用程序选项几类，下面一起去介绍它们。     --help    --help-admin    --help-proxy    --help-all ---- 以上四个选项均用于获取帮助信息；     --proxy-address=host:port ---- 代理服务监听的地址和端口；    --admin-address=host:port ---- 管理模块监听的地址和端口；    --proxy-backend-addresses=host:port ---- 后端mysql服务器的地址和端口；    --proxy-read-only-backend-addresses=host:port ---- 后端只读mysql服务器的地址和端口；    --proxy-lua-script=file_name ---- 完成mysql代理功能的Lua脚本；    --daemon ---- 以守护进程模式启动mysql-proxy；    --keepalive ---- 在mysql-proxy崩溃时尝试重启之；    --log-file=/path/to/log_file_name ---- 日志文件名称；    --log-level=level ---- 日志级别；    --log-use-syslog ---- 基于syslog记录日志；    --plugins=plugin,.. ---- 在mysql-proxy启动时加载的插件；    --user=user_name ---- 运行mysql-proxy进程的用户；    --defaults-file=/path/to/conf_file_name ---- 默认使用的配置文件路径；其配置段使用[mysql-proxy]标识；    --proxy-skip-profiling ---- 禁用profile；    --pid-file=/path/to/pid_file_name ---- 进程文件名；

(5)复制如下内容建立admin.lua文件，将其保存至/usr/local/mysql-proxy/share/doc/mysql-proxy/目录中。

# vim /usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua--[[ $%BEGINLICENSE%$ Copyright (c) 2007, 2012, Oracle and/or its affiliates. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA $%ENDLICENSE%$ --]]function set_error(errmsg)     proxy.response = {        type = proxy.MYSQLD_PACKET_ERR,        errmsg = errmsg or "error"    }endfunction read_query(packet)    if packet:byte() ~= proxy.COM_QUERY then        set_error("[admin] we only handle text-based queries (COM_QUERY)")        return proxy.PROXY_SEND_RESULT    end    local query = packet:sub(2)    local rows = { }    local fields = { }    if query:lower() == "select * from backends" then        fields = {             { name = "backend_ndx",               type = proxy.MYSQL_TYPE_LONG },            { name = "address",              type = proxy.MYSQL_TYPE_STRING },            { name = "state",              type = proxy.MYSQL_TYPE_STRING },            { name = "type",              type = proxy.MYSQL_TYPE_STRING },            { name = "uuid",              type = proxy.MYSQL_TYPE_STRING },            { name = "connected_clients",               type = proxy.MYSQL_TYPE_LONG },        }        for i = 1, #proxy.global.backends do            local states = {                "unknown",                "up",                "down"            }            local types = {                "unknown",                "rw",                "ro"            }            local b = proxy.global.backends[i]            rows[#rows + 1] = {                i,                b.dst.name,          -- configured backend address                states[b.state + 1], -- the C-id is pushed down starting at 0                types[b.type + 1],   -- the C-id is pushed down starting at 0                b.uuid,              -- the MySQL Server's UUID if it is managed                b.connected_clients  -- currently connected clients            }        end    elseif query:lower() == "select * from help" then        fields = {             { name = "command",               type = proxy.MYSQL_TYPE_STRING },            { name = "description",               type = proxy.MYSQL_TYPE_STRING },        }        rows[#rows + 1] = { "SELECT * FROM help", "shows this help" }        rows[#rows + 1] = { "SELECT * FROM backends", "lists the backends and their state" }    else        set_error("use 'SELECT * FROM help' to see the supported commands")        return proxy.PROXY_SEND_RESULT    end    proxy.response = {        type = proxy.MYSQLD_PACKET_OK,        resultset = {            fields = fields,            rows = rows        }    }    return proxy.PROXY_SEND_RESULTend--授予执行权限# chown mysql-proxy.mysql-proxy /usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua# chmod +x /usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua

(6)启动mysql-proxy代理服务

# service mysql-proxy start# ss -tnlLISTEN      0      128                                           *:4041                                         *:*     LISTEN      0      128                                           *:3306                                         *:*

(7)配置Master与Slave主机为主从复制模式

Master配置:# mkdir -pv /mydata/binlogs# chown -R mysql.mysql /mydata/binlogs/# vim /etc/mysql/my.cnfserver-id       = 1log-bin=/mydata/binlogs/master-binSlave配置:# mkdir -pv /mydata/relaylogs# chown -R mysql.mysql /mydata/relaylogs# vim /etc/mysql/my.cnfserver-id       = 2relay-log=/mydata/relaylogs/relay-bin

(8)在Master主机上创建拥有权限的用户

MariaDB [(none)]> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'repluser'@'172.16.%.%' IDENTIFIED BY 'replpass';MariaDB [(none)]> FLUSH PRIVILEGES;

(9)连接Master服务器

MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='172.16.100.7',MASTER_USER='repluser',MASTER_PASSWORD='replpass';MariaDB [(none)]> START SLAVE;

(10)创建远程连接用户

MariaDB [(none)]> GRANT ALL ON *.* TO 'admin'@'172.16.%.%' IDENTIFIED BY 'admin';MariaDB [(none)]> FLUSH PRIVILEGES;

(11)管理功能测试

--代理服务器上操作# mysql -uadmin -padmin -h272.16.100.9 --port=4041mysql> SELECT * FROM backends;+-------------+-------------------+---------+------+------+-------------------+| backend_ndx | address           | state   | type | uuid | connected_clients |+-------------+-------------------+---------+------+------+-------------------+|           1 | 172.16.100.7:3306 | unknown | rw   | NULL |                 0 ||           2 | 172.16.100.8:3306 | unknown | ro   | NULL |                 0 |+-------------+-------------------+---------+------+------+-------------------+

(12)通过代理服务器连接服务器及读写测试

注意： 实验环境中  172.16.100.7 为主服务器           172.16.100.8 为从服务器172.16.100.9 为代理服务器--通过代理服务器连接服务器#  mysql -h272.16.100.9 -uadmin -padminmysql> CREATE DATABASE samleedb;--在主服务器和从服务器上使用下面命令进行监控--Master进行写入操作的时候状态# tcpdump -i any -nn -XX -A -p port 3306 and src 172.16.100.9tcpdump: verbose output suppressed, use -v or -vv for full protocol decodelistening on any, link-type LINUX_SLL (Linux cooked), capture size 65535 bytes17:05:54.617412 IP 172.16.100.9.40783 > 172.16.100.7.3306: Flags [P.], seq 2523263157:2523263186, ack 2431684210, win 457, options [nop,nop,TS val 12587304 ecr 11832810], length 29    0x0000:  0000 0001 0006 000c 29d4 3452 0000 0800  ........).4R....    0x0010:  4508 0051 6cf2 4000 4006 ad7b ac10 6409  E..Ql.@.@..{..d.    0x0020:  ac10 6407 9f4f 0cea 9665 f0b5 90f0 8e72  ..d..O...e.....r    0x0030:  8018 01c9 88ae 0000 0101 080a 00c0 1128  ...............(    0x0040:  00b4 8dea 1900 0000 0343 5245 4154 4520  .........CREATE.    0x0050:  4441 5441 4241 5345 2073 616d 6c65 6564  DATABASE.samleed    0x0060:  62                                           b--在代理服务器管理:mysql> SELECT * FROM backends;+-------------+-------------------+---------+------+------+-------------------+| backend_ndx | address           | state   | type | uuid | connected_clients |+-------------+-------------------+---------+------+------+-------------------+|           1 | 172.16.100.7:3306 | up      | rw   | NULL |                 0 ||           2 | 172.16.100.8:3306 | unknown | ro   | NULL |                 0 |+-------------+-------------------+---------+------+------+-------------------+

(13)使用循环脚本验证请求发往的方向

向mysql-proxy执行读请求     # for i in {1..10}; do mysql -h272.16.100.9 -uadmin -padmin -e 'select * from hellodb.classes limit 1';done在主服务器和从服务器上使用下面命令进行监控。     # tcpdump -i any -nn -XX -A -p port 3306 and src 172.16.100.9可以发现当读请求量增大时，两边主机都可以看见读报文被截获。      向mysql-proxy执行写请求    MariaDB [hellodb]> source /tmp/hellodb.sql 只有在master端可以看到截获报文     通过上面测试后，可以看到两个服务器状态都是upmysql> SELECT * FROM backends;+-------------+-------------------+-------+------+------+-------------------+| backend_ndx | address           | state | type | uuid | connected_clients |+-------------+-------------------+-------+------+------+-------------------+|           1 | 172.16.100.7:3306 | up    | rw   | NULL |                 0 ||           2 | 172.16.100.8:3306 | up    | ro   | NULL |                 0 |+-------------+-------------------+-------+------+------+-------------------+

以上通过mysql-proxy实现读写分离全部过程。