mysql-proxy实现读写分离

一、安装配置mysql-proxy:

1.1下载所需要的版本，这里的系统平台为centos6.5 64位系统，因此就以mysql-proxy-0.8.3-linux-glibc2.3-x86-64bit.tar.gz为例

# tar xf mysql-proxy-0.8.3-linux-glibc2.3-x86-64bit.tar.gz -C /usr/local
# cd /usr/local
# ln -sv mysql-proxy-0.8.3-linux-glibc2.3-x86-64bit mysql-proxy
# cd mysql-proxy

添加代理用户

# useradd mysql-proxy

1.2 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

1.3 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=192.168.8.40:3306 --proxy-read-only-backend-addresses=192.168.8.43:3306 --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。

1.4 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；

1.5、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

直接编辑lua脚本 # vim share/doc/mysql-proxy/admin.lua 格式无法控制
通过将代码拷贝到vim /root/admin.txt拷贝进目标文件中
# cat /root/admin.txt > 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"
}
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

6、测试

# service mysql-proxy start

报错：
ERROR 1045 (28000): Access denied for user 'admin'@'localhost' (using password: YES)


通过查看错误日志：
# cd /var/log
# tail message
-------------------------------
2015-12-25 23:17:39: (critical) network-socket.c:451: bind(0.0.0.0:3306) failed: Address already in use (98)
Dec 25 23:17:39 centossz008 mysql-proxy: 2015-12-25 23:17:39: (critical) chassis-mainloop.c:267: applying config of plugin proxy failed
Dec 25 23:17:39 centossz008 mysql-proxy: 2015-12-25 23:17:39: (critical) mysql-proxy-cli.c:597: Failure from chassis_mainloop. Shutting down.
-------------------------------


发现是本机启动了mysql服务，停用再重新启动mysql-proxy即可

6.1 管理功能测试

# mysql -uadmin -padmin -h192.168.8.44 --port=4041


MySQL [(none)]> select * from help;
ERROR 1105 (07000): MySQL Proxy Lua script failed to load. Check the error log.


再次查看日志：
Dec 25 23:51:33 centossz008 mysql-proxy: 2015-12-25 23:51:33: (critical) last message repeated 2 times
Dec 25 23:51:33 centossz008 mysql-proxy: 2015-12-25 23:51:33: (critical) network-mysqld-lua.c:234: lua_load_file(/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua) failed: [string "/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"]:1: '=' expected near '%'


发现/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua 文件少了前面的--[[ 
添加即可


MySQL [(none)]> select * from help;
+------------------------+------------------------------------+
| command                | description                        |
+------------------------+------------------------------------+
| SELECT * FROM help     | shows this help                    |
| SELECT * FROM backends | lists the backends and their state |
+------------------------+------------------------------------+
2 rows in set (0.00 sec)


MySQL [(none)]> select * from backends;
+-------------+-------------------+---------+------+------+-------------------+
| backend_ndx | address           | state   | type | uuid | connected_clients |
+-------------+-------------------+---------+------+------+-------------------+
|           1 | 192.168.8.40:3306 | unknown | rw   | NULL |                 0 |
|           2 | 192.168.8.43:3306 | unknown | ro   | NULL |                 0 |
+-------------+-------------------+---------+------+------+-------------------+
2 rows in set (0.00 sec)