B7-Haproxy 四層負載均衡

Haproxy 四層負載均衡


拓撲：                 
  app  ---->  mysql_master(write)
    |
 haproxy(read)
    |
mysql_slave*N



一 Haproxy 部分
1 haproxy 代碼

listen  bbs_slave   10.0.100.82:3306
        mode tcp          #配置TCP模式
        maxconn 2000
        balance roundrobin
        #option httpchk OPTIONS * HTTP/1.1\r\nHost:\ www
        server  slave01 10.0.100.75:3306 check port 9120 inter 5000 rise 3 fall 3 weight 3
        server  slave02 10.0.100.76:3306 check port 9120 inter 5000 rise 3 fall 3 weight 3
        srvtimeout      20000

二 Mysql 部分
2.1 mysql replication 監控腳本

cat /usr/local/bin/mysqlrep_status.sh
#!/bin/bash
#
# /usr/local/bin/mysqlrep_status.sh
#
# This script checks if a mysql server is healthy running on localhost. It will
# return:
#
# "HTTP/1.x 200 OK\r" (if mysql is running smoothly)
#
# – OR –
#
# "HTTP/1.x 503 Internal Server Error\r" (else)
#

mysql=/usr/local/bin/mysql
mysql_host="localhost"
mysql_port="3306"
mysql_username="root"
mysql_password="dongnan"
#
$mysql -u${mysql_username} -p${mysql_password} -e "show full processlist;" >/tmp/processlist.txt
$mysql -u${mysql_username} -p${mysql_password} -e "show slave status\G;" >/tmp/rep.txt
iostat=`awk '/Slave_IO_Running/ {print $2}' /tmp/rep.txt`
sqlstat=`awk '/Slave_SQL_Running/ {print $2}' /tmp/rep.txt`

if [ "$iostat" = "Yes" ] && [ "$sqlstat" = "Yes" ];then
    /bin/echo -e "HTTP/1.1 200 OK\r\n"
else
    /bin/echo -e "HTTP/1.1 503 Service Unavailable\r\n"
fi

2.2 配置 xinetd 
//定義服務,服務名必定要在 /etc/services列出

tail -n1 /etc/services

mysql_rep_check 9120/tcp

//定義 super daemon    

cat >> /etc/xinetd.d/mysql_rep_check << EOF
# default: off
#
service mysql_rep_check
{
        flags           = REUSE
        socket_type     = stream
        wait            = no
        user            = nobody
        server          = /usr/local/bin/mysqlrep_status.sh
        log_on_failure  += USERID
        disable         = no

}

EOF

2.3 重啓xinetd

/etc/init.d/xinetd restart

2.4 xinetd 日誌

tail -n1 /var/log/messages

Nov  8 16:44:27 one xinetd[12224]: Started working: 1 available service

2.5 查看自定義服務端口

lsof -i :9120

COMMAND   PID USER   FD   TYPE  DEVICE SIZE NODE NAME
xinetd  12224 root    5u  IPv4 1078320       TCP *:mysql_rep_check (LISTEN)

2.6 測試

telnet 127.0.0.1 9120

Trying 127.0.0.1...
Connected to one.test.com (127.0.0.1).
Escape character is '^]'.
HTTP/1.1 200 OK

Connection closed by foreign host.

流程
(1)應用服務器
(2)鏈接HAProxy的10.0.100.82:3306，根據算法，分配到一臺mysql slave。
(3)檢測slave的9120端口是否返回http 200狀態碼。
(4)返回200 狀態碼，HAProxy 返回正常，繼續服務。
(5)返回503，剔除該slave，並將mysql請求轉發到另一臺slave。


參考
基於Keepalived+Haproxy搭建四層負載均衡器

MySQL從庫集羣方案之HAProxy篇


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