在Linux 下 用HAProxy给MySQL做负载均衡

写在前面：由于mysql
master 主机上的xinet传给Haproxy的状态不稳定，haproxy会不停的切换mysql主机，造成网站应用反应慢，建议做mysql主从服务器者谨用（用mysql-proxy读写分离代替），mysql cluster方案可以用。

1. 添加监控MySQL状态的端口

在db服务器上(每台都一样)

安装xinetd 

# yum install xinetd

# vi /etc/services

================================================

mysqlcheck      6033/tcp                        # MySQL status check

2. 使用xinetd守护进程运行MySQL状态检测

在db服务器上

# cat /etc/xinetd.d/mysqlchk

=================================================

service mysqlcheck

{

        disable         = no

        flags           = REUSE

        socket_type     = stream

        port            = 6033

        wait            = no

        user            = root

        server          = /usr/local/haproxy/sbin/mysqlchk_status.sh

        log_on_failure  += USERID

        only_from       = 192.168.3.0/24 # recommended to put the IPs that need

                                    # to connect exclusively (security purposes)

}

3. 状态检测脚本

在db服务器上

# vi /usr/local/haproxy/sbin/mysqlchk_status.sh

================================================

 #/bin/bash

MYSQL_HOST="localhost"

MYSQL_PORT="3306"

MYSQL_USERNAME="root"

MYSQL_PASSWORD="123456"

 

#ERROR_MSG=/usr/bin/mysql --host=$MYSQL_HOST --port=$MYSQL_PORT --user=$MYSQL_USERNAME --password=$MYSQL_PASSWORD -e "show databases;"

 

ERROR_MSG=`ps -e | grep mysqld |wc -l`

 

if [ "$ERROR_MSG" != "0" ]

then

        # mysql is fine, return http 200

        /bin/echo -e "HTTP/1.1 200 OK\r\n"

        /bin/echo -e "Content-Type: Content-Type: text/plain\r\n"

        /bin/echo -e "\r\n"

        /bin/echo -e "MySQL is running.\r\n"

        /bin/echo -e "\r\n"

else

        # mysql is fine, return http 503

        /bin/echo -e "HTTP/1.1 503 Service Unavailable\r\n"

        /bin/echo -e "Content-Type: Content-Type: text/plain\r\n"

        /bin/echo -e "\r\n"

        /bin/echo -e "MySQL is *down*.\r\n"

        /bin/echo -e "\r\n"

fi

 ==================================================================

# chmod +x  /usr/local/haproxy/sbin/mysqlchk_status.sh

# service xinetd stop

# service xinetd start

# chown haproxy.haproxy /usr/local/haproxy/sbin/mysqlchk_status.sh

4. HAproxy日志

# touch /var/log/haproxy.log

# chown haproxy.haproxy /var/log/haproxy.log

编辑/etc/syslog.conf文件，添加如下语句

local0.*                                                /var/log/haproxy.log

5. HAProxy配置文件

在均衡服务器上

[root@localhost htdocs]# cat /usr/local/haproxy/conf/haproxy.conf

================================================================

global

        maxconn 4096

        daemon

        pidfile /usr/local/haproxy/run/haproxy.pid

        #debug

        #quiet

        user haproxy

        group haproxy

 

defaults

        log     global

        mode    http

        option  httplog

        option  dontlognull

        log 127.0.0.1 local0

        retries 3

        option redispatch

        maxconn 2000

        contimeout      5000

        clitimeout      50000 #如果程序执行时间很长，把这个值调大一些 我在后面多加两个0改成5000000 毫秒

        srvtimeout      50000

 

listen  admin_stats 192.168.0.1:80

        mode        http

        stats uri   /dbs

        stats realm     Global\ statistics

        stats auth  test:123456

 

listen  proxy-mysql 0.0.0.0:23306

        mode tcp

        balance roundrobin

        option httpchk OPTIONS * HTTP/1.1\r\nHost:\ www

        server db01 192.168.0.1:3306 weight 1 check port 6033 inter 1s rise 2 fall 2

        server db02 192.168.0.2:3306 weight 1 check port 6033 inter 1s rise 2 fall 2

        option tcpka

===================================================

6. HAProxy启动脚本

在均衡服务器上

# cat /etc/init.d/haproxy

===================================================

 #! /bin/sh

set -e

 

PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/haproxy/sbin

PROGDIR=/usr/local/haproxy

PROGNAME=haproxy

DAEMON=$PROGDIR/sbin/$PROGNAME

CONFIG=$PROGDIR/conf/$PROGNAME.conf

PIDFILE=$PROGDIR/run/$PROGNAME.pid

DESC="HAProxy daemon"

SCRIPTNAME=/etc/init.d/$PROGNAME

 

# Gracefully exit if the package has been removed.

test -x $DAEMON || exit 0

 

start()

{

        echo -n "Starting $DESC: $PROGNAME"

        $DAEMON -f $CONFIG

        echo "."

}

 

stop()

{

        echo -n "Stopping $DESC: $PROGNAME"

        haproxy_pid=cat $PIDFILE

        kill $haproxy_pid

        echo "."

}

 

restart()

{

        echo -n "Restarting $DESC: $PROGNAME"

        $DAEMON -f $CONFIG -p $PIDFILE -sf $(cat $PIDFILE)

        echo "."

}

 

case "$1" in

  start)

        start

        ;;

  stop)

        stop

        ;;

  restart)

        restart

        ;;

  *)

        echo "Usage: $SCRIPTNAME {start|stop|restart}" >&2

        exit 1

        ;;

esac

 

exit 0