MySQL Proxy 實現MySQLDB 讀寫分離

時間  2019-12-09
標籤 mysql proxy 實現 mysqldb 讀寫 分離 欄目 MySQL 简体版
原文   原文鏈接

1、簡述html

MySQL Proxy是一個處於你的client端和MySQL server端之間的簡單程序，它能夠監測、分析或改變它們的通訊。它使用靈活，沒有限制，常見的用途包括：負載平衡，故障、查詢分析，查詢過濾和修改等等。
MySQL Proxy就是這麼一箇中間層代理，簡單的說，MySQL Proxy就是一個鏈接池，負責將前臺應用的鏈接請求轉發給後臺的數據庫，而且經過使用lua腳本，能夠實現複雜的鏈接控制和過濾，從而實現讀寫分離和負 載平衡。對於應用來講，MySQL Proxy是徹底透明的，應用則只須要鏈接到MySQL Proxy的監聽端口便可。固然，這樣proxy機器可能成爲單點失效，但徹底可使用多個proxy機器作爲冗餘，在應用服務器的鏈接池配置中配置到多 個proxy的鏈接參數便可。
MySQL Proxy更強大的一項功能是實現「讀寫分離」，基本原理是讓主數據庫處理事務性查詢，讓從庫處理SELECT查詢。數據庫複製被用來把事務性查詢致使的變動同步到集羣中的從庫。 　

2、對MariaDB作主從複製mysql

關於如何對MariaDB作主從複製，請移步本人博客MariaDB 主從複製 linux

3、安裝web

   1.能夠經過rpm安裝，其會提供配置文件及服務腳本，可是沒有讀寫分享腳本redis

 2.經過編譯安裝sql

①、源碼安裝時，MySQL proxy的依賴關係：    數據庫

           libevent 1.x or higher (1.3b or later is preferred).後端

           lua 5.1.x or higher.bash

           glib2 2.6.0 or higher.服務器

           pkg-config.

           libtool 1.5 or higher.

           MySQL 5.0.x or higher developer files.

       ②、下載源碼包，編譯安裝

# tar zxf mysql-proxy-0.8.2.tar.gz
# cd mysql-proxy-0.8.2
# ./configure
# make
# make check
若是管理員有密碼，上面的步驟則須要使用以下格式進行：
# MYSQL_PASSWORD=root_pwd make check
# make install
默認狀況下， mysql-proxy安裝在/usr/local/sbin/mysql-proxy，而Lua示例腳本安裝在/usr/local/share目錄中。

3.經過通用二進制格式安裝

①、下載解壓。這裏的系統平臺爲rhel6.5 64位系統

[root@httpweb ~]# wget http://mirror.sohu.com/mysql/MySQL-Proxy/mysql-proxy-0.8.4-linux-el6-x86-64bit.tar.gz
[root@httpweb ~]# tar xf mysql-proxy-0.8.4-linux-el6-x86-64bit.tar.gz
[root@httpweb ~]# mv mysql-proxy-0.8.4-linux-el6-x86-64bit /usr/local/mysql-proxy

②、添加代理用戶

[root@httpweb mysql-proxy]# useradd mysql-proxy

 ③、爲mysql-proxy提供SysV服務腳本

#!/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

 

將上述內容保存爲/etc/init.d/mysql-proxy，給予執行權限，然後添加至服務列表

[root@httpweb mysql-proxy]# vi /etc/init.d/mysql-proxy
[root@httpweb mysql-proxy]# chmod +x /etc/init.d/mysql-proxy
[root@httpweb mysql-proxy]# chkconfig --add mysql-proxy

④、爲服務腳本提供配置文件/etc/sysconfig/mysql-proxy

#Options for mysql-proxy
ADMIN_USER="firefox"
ADMIN_PASSWORD="firefox"
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=192.168.1.200:3306 --proxy-read-only-backend-addresses=192.168.1.202:3306 --proxy-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua"
其中的proxy-backend-addresses選項和proxy-read-only-backend-addresses選項都可重複使用屢次，以實現指定多個讀寫服務器或只讀服務器。

 

⑤、mysql-proxy的配置選項

 mysql-proxy的配置選項大體可分爲幫助選項、管理選項、代理選項及應用程序選項幾類，下面一塊兒去介紹它們。

           --help

           --help-admin

           --help-proxy

           --help-all ———— 以上四個選項均用於獲取幫助信息；

           --proxy-address=host:port ———— 代理服務監聽的地址和端口；

           --admin-address=host:port ———— 管理模塊監聽的地址和端口；

           --proxy-backend-addresses=host:port ———— 後端mysql服務器的地址和端口；

           --proxy-read-only-backend-addresses=host:port ———— 後端只讀mysql服務器的地址和端口；

           --proxy-lua-script=file_name ———— 完成mysql代理功能的Lua腳本；

           --daemon ———— 以守護進程模式啓動mysql-proxy；

           --keepalive ———— 在mysql-proxy崩潰時嘗試重啓之；

           --log-file=/path/to/log_file_name ———— 日誌文件名稱；

           --log-level=level ———— 日誌級別；

           --log-use-syslog ———— 基於syslog記錄日誌；

           --plugins=plugin,.. ———— 在mysql-proxy啓動時加載的插件；

           --user=user_name ———— 運行mysql-proxy進程的用戶；

           --defaults-file=/path/to/conf_file_name ———— 默認使用的配置文件路徑；其配置段使用[mysql-proxy]標識；

           --proxy-skip-profiling ———— 禁用profile；

           --pid-file=/path/to/pid_file_name ———— 進程文件名； 

⑥、提供admin.lua文件，將其保存至/usr/local/mysql-proxy/share/mysql-proxy/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

 

 ⑦、測試

啓動服務；

 service mysql-proxy start

 

管理功能測試      

wKiom1NOlV_BSlwLAABNBtSUtm0691.jpg

能夠看到4041端口和3306端口以及處於監聽狀態

咱們在主服務器上授予201數據庫寫的權限

MariaDB [(none)]>  grant all on *.* to 'firefox'@'192.168.1.201' identified by 'firefox';
MariaDB [(none)]> flush privileges;
[root@httpweb mysql-proxy]# mysql -ufirefox -pfirefox -h192.168.1.201 --port=3306
咱們能夠看到咱們在mysql-proxy的能夠登陸數據庫了

 

查看是否配置成功   

[root@httpweb ~]# mysql -ufirefox -pfirefox -h192.168.1.201 --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
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
mysql> select * from backends;
+-------------+--------------------+---------+------+------+-------------------+
| backend_ndx | address            | state   | type | uuid | connected_clients |
+-------------+--------------------+---------+------+------+-------------------+
|           1 | 192.168.1.200:3306 | up      | rw   | NULL |                 0 |
|           2 | 192.168.1.202:3306 | up      | ro   | NULL |                 0 |
+-------------+--------------------+---------+------+------+-------------------+

 

咱們的程序就能夠實現真正意義上的讀寫分離了，大功告成，因爲本人水平有限，請各位大神多多批評指正

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