基于mysql-proxy读写分离

一、可以使用rpm包安装，需要安装epel软件包库，或者直接从官网下载rpm包；

二、安装配置mysql-proxy:

2.1 下载所需要的版本，这里的系统平台为rhel6.4 32位系统，因此就以mysql-proxy-0.8.1-linux-glibc2.3-x86-32bit.tar.gz为例。

# tar xf mysql-proxy-0.8.1-linux-glibc2.3-x86-32bit.tar.gz -C /usr/local

# cd /usr/local

# ln -sv mysql-proxy-0.8.1-linux-glibc2.3-x86-32bit  mysql-proxy

添加代理用户

# useradd mysql-proxy

2.2 为mysql-proxy提供SysV服务脚本，内容如下所示

#!/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/functions

prog="/usr/local/mysql-proxy/bin/mysql-proxy"

# Source networking configuration.

if [ -f /etc/sysconfig/network ]; then

    . /etc/sysconfig/network

fi

# 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.pid

PROXY_USER="mysql-proxy"

# Source mysql-proxy configuration.

if [ -f /etc/sysconfig/mysql-proxy ]; then

    . /etc/sysconfig/mysql-proxy

fi

RETVAL=0

start() {

    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

        ;;

esac

exit $RETVAL

将上述内容保存为/etc/rc.d/init.d/mysql-proxy，给予执行权限，而后加入到服务列表。

# chmod +x /etc/rc.d/init.d/mysql-proxy

# chkconfig --add mysql-proxy

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

# Options for mysql-proxy 

ADMIN_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"

其中最后一行，需要按实际场景进行修改，例如：

PROXY_OPTIONS="--daemon --log-level=info --log-use-syslog --plugins=proxy --plugins=admin --proxy-backend-addresses=192.168.1.21:3306 --proxy-read-only-backend-addresses=192.168.1.211:3306 --proxy-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua"

其中的proxy-backend-addresses选项和proxy-read-only-backend-addresses选项均可重复使用多次，以实现指定多个读写服务器或只读服务器。

2.4 mysql-proxy的配置选项

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；

3、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。

--[[ $%BEGINLICENSE%$

 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"

}

end

function 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_RESULT

end

4、测试

4.1 管理功能测试

# mysql -uadmin -padmin -192.168.1.22 --port=4041 

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 1

Server version: 5.0.99-agent-admin

Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the buffer.

mysql> SELECT * FROM backends;

+-------------+--------------------+---------+------+------+-------------------+
| backend_ndx | address            | state   | type | uuid | connected_clients |
+-------------+--------------------+---------+------+------+-------------------+
|           1 | 192.168.1.21:3306  | up      | rw   | NULL |                 0 |
|           2 | 192.168.1.211:3306 | unknown | ro   | NULL |                 0 |
+-------------+--------------------+---------+------+------+-------------------+
2 rows in set (0.00 sec)

4.2 读写分离测试

# mysql -uroot  -h192.168.1.22 --port=4040 -p

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