使用mysql-proxy实现mysql的读写分离

Posted 2021-03-21 小雨淅淅o0

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前言：

　　mysql读写分离是指让master处理写操作，让slave处理读操作，非常适用于读操作量比较大的场景，可减轻master的压力。使用mysql-proxy实现mysql的读写分离，mysql-proxy实际上是作为后端mysql主从服务器的代理，它直接接受客户端的请求，对SQL语句进行分析，判断出是读操作还是写操作，然后分发至对应的mysql服务器上。mysql-proxy是官方提供的mysql中间件产品可以实现负载平衡，读写分离，failover等MySQL Proxy就是这么一个中间层代理，简单的说，MySQL Proxy就是一个连接池，负责将前台应用的连接请求转发给后台的数据库，并且通过使用lua脚本，可以实现复杂的连接控制和过滤，从而实现读写分离和负载平衡。对于应用来说，MySQL Proxy是完全透明的，应用则只需要连接到MySQL Proxy的监听端口即可。当然，这样proxy机器可能成为单点失效，但完全可以使用多个proxy机器做为冗余，在应用服务器的连接池配置中配置到多个proxy的连接参数即可。

实验系统：CentOS 6.6_x86_64

实验前提：防火墙和selinux都关闭

实验说明：本实验共有4台主机，IP分配如拓扑

实验软件：mariadb-10.0.20　　mysql-proxy-0.8.5-linux-el6-x86-64bit

下载地址：http://pan.baidu.com/s/1i3F5Pop

实验拓扑：

一、准备工作：

　　1.将主机名称改为如下所示：

　　2.将hosts文件添加如下内容：

　　3.master、slave1和slave2安装mariadb：

tar xf mariadb-10.0.20-linux-x86_64.tar.gz  -C /usr/local/
cd /usr/local/
ln -sv mariadb-10.0.20-linux-x86_64 mysql
useradd -r mysql
mkdir -pv /mydata/data
chown -R mysql.mysql /mydata/data/
cd mysql/
chown -R root.mysql .
scripts/mysql_install_db --user=mysql --datadir=/mydata/data/
cp support-files/my-large.cnf /etc/my.cnf
cp support-files/mysql.server /etc/init.d/mysqld
chkconfig --add mysqld
chkconfig mysqld on

二、配置主从复制

　　1.master上配置my.cnf：

[mysqld]
server-id       = 1
datadir = /mydata/data
log-bin = /mydata/data/master-bin
binlog_format = ROW
sync_binlog = 1                        //确保每次事务提交之前都能将二进制日志同步磁盘上

　　2.slave1上配置my.cnf：

[mysqld]
#log-bin=mysql-bin
#binlog_format=mixed
server-id       = 2
datadir = /mydata/data
relay_log = /mydata/data/relay-log
read_only = 1
sync_master_info = 1                   //及时同步master文件
sync_relay_log = 1                     //及时同步relay-log文件
sync_relay_log_info = 1                //及时同步relay-log-info文件

　　3.slave2上配置my.cnf：

[mysqld]
#log-bin=mysql-bin
#binlog_format=mixed
server-id       = 3
datadir = /mydata/data
relay_log = /mydata/data/relay-log
read_only = 1
sync_master_info = 1
sync_relay_log = 1
sync_relay_log_info = 1

　　4.在master上创建复制用户：

service mysqld start
/usr/local/mysql/bin/mysql
------------------------------------------->
GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO \'slave\'@\'192.168.19.%\' IDENTIFIED BY \'123456\';
FLUSH PRIVILEGES;

　　5.在master上查看二进制日志位置：

SHOW MASTER LOGS;

　　6.两台slave上操作：

CHANGE MASTER TO MASTER_HOST=\'master\',MASTER_USER=\'slave\',MASTER_PASSWORD=\'123456\',MASTER_LOG_FILE=\'master-bin.000001\',MASTER_LOG_POS=637;
START SLAVE;
SHOW SLAVE STATUS\\G

三、安装mysql-proxy

　　1.此实验中19.79为mysql-proxy服务器，所以软件安装在此主机上：

tar xf mysql-proxy-0.8.5-linux-el6-x86-64bit.tar.gz -C /usr/local/
cd /usr/local/
ln -sv mysql-proxy-0.8.5-linux-el6-x86-64bit mysql-proxy
useradd -r mysql-proxy

　　2.提供服务脚本：

vim /etc/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/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
<---------------------------------------------------------
chmod +x /etc/init.d/mysql-proxy
chkconfig --add mysql-proxy

　　3.为服务脚本提供配置文件：

vim /etc/sysconfig/mysql-proxy
--------------------------------------------------------->
# 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 --plugins=proxy --plugins=admin --proxy-backend-addresses=192.168.19.66:3306 --proxy-read-only-backend-addresses=192.168.19.74:3306
 --proxy-read-only-backend-addresses=192.168.19.76:3306 --proxy-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua"

//--daemon：以守护进程模式启动mysql-proxy
//--proxy-backend-addresses：后端可读写的mysql服务器的地址和端口
//--proxy-read-only-backend-addresses：后端只读mysql服务器的地址和端口
//--proxy-lua-script：完成mysql代理功能的Lua脚本

　　4.提供admin.lua文件：

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"
}
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

　　5.为了使实验结果更明显，编辑rw-splitting.lua文件中的其中2个数值：

vim /usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua
--------------------------------------------------------------------------->
if not proxy.global.config.rwsplit then
        proxy.global.config.rwsplit = {
                min_idle_connections = 1,     //默认为4
                max_idle_connections = 1, 　 　//默认为8

                is_debug = false
        }
end
          //mysql-proxy会检测客户端连接，当连接没有超过min_idle_connections预设值时, 不会进行读写分离, 即查询操作会发生到Master上。

5.启动mysql-proxy：

service mysql-proxy start
ss -tnlp                      //查看端口

　　6.连接测试：

yum -y install mysql                               //如果没有mysql客户端的话执行此步
mysql -uadmin -padmin -h192.168.19.79 --port=4041
------------------------------------------------------------>
SELECT * FROM backends;
+-------------+--------------------+---------+------+------+-------------------+
| backend_ndx | address            | state   | type | uuid | connected_clients |
+-------------+--------------------+---------+------+------+-------------------+
|           1 | 192.168.19.66:3306 | unknown | rw   | NULL |                 0 |
|           2 | 192.168.19.74:3306 | unknown | ro   | NULL |                 0 |
|           3 | 192.168.19.76:3306 | unknown | ro   | NULL |                 0 |
+-------------+--------------------+---------+------+------+-------------------+

四、读写分离测试：

　　1.在master上创建测试用户：

GRANT ALL ON *.* TO \'jason\'@\'192.168.19.%\' IDENTIFIED BY \'123456\';
FLUSH PRIVILEGES;

　　2.分别在三台mariadb服务器上抓包：

　　　　master：

tcpdump -i eth0 -nn -XX ip dst 192.168.19.66 and tcp dst port 3306      //目标是19.66并且端口是3306

　　　　slave1：

tcpdump -i eth0 -nn -XX ip dst 192.168.19.74 and tcp dst port 3306

　　　　slave2：

tcpdump -i eth0 -nn -XX ip dst 192.168.19.76 and tcp dst port 3306

　　3.mysql-proxy上进行数据库操作：

mysql -ujason -p123456 -h192.168.19.79
------------------------------------------------->
CREATE DATABASE hello;
USE mysql;
SELECT * FROM user;             //可以用额外的主机多执行几次

　　　　在master上的抓包信息：

　　　　在slave上的抓包信息：

　　4.查看状态，在proxy上操作，可以看到状态全部为up：

mysql -uadmin -padmin -h192.168.19.79 --port=4041
------------------------------------------------------------->
SELECT * FROM backends;
+-------------+--------------------+-------+------+------+-------------------+
| backend_ndx | address            | state | type | uuid | connected_clients |
+-------------+--------------------+-------+------+------+-------------------+
|           1 | 192.168.19.66:3306 | up    | rw   | NULL |                 0 |
|           2 | 192.168.19.74:3306 | up    | ro   | NULL |                 0 |
|           3 | 192.168.19.76:3306 | up    | ro   | NULL |                 0 |
+-------------+--------------------+-------+------+------+-------------------+

五、拓展实验

　　1.在proxy上安装httpd和php：

yum install httpd php php-mysql
service httpd start

　　2.让httpd可以支持index.php首页，然后放入wordpress页面文件，创建wordpress数据库并安装：

　　3.安装完后修改wordpress的配置文件，将master地址改为proxy的：

vim /var/www/html/wp-config.php

　　4.访问测试并抓包：

　　　　master：

　　　　slave：

转载链接：https://www.cnblogs.com/tae44/p/4701226.html

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