最近用HAproxy+keepalived+mysql复制测试高可用性Linux系统集群。

   HAProxy是一款免费的提供高可用性、负载均衡以及基于TCP（第四层）和HTTP（第七层）应用的代理软件，借助HAProxy可以快速并且可靠的提供基于TCP和HTTP应用的代理解决方案。    Keepalived主要作用是LoadBalance master和LoadBalance backup之间的健康检查，实现故障转换。    Mysql Replication主要作用是提高mysql并处理数据的能力以及实现容灾备份的作用。

项目拓扑图：

Haproxy服务器及其IP地址规划：

项目实施：

1.Mysql主从复制配置。

1)在master服务器上创建mysql用户（授权复制账户）。grant replication slave on *.* to'rep'@'192.168.1.244'identified by 'rep123';2)编辑master服务器的mysql配置文件my.cnf。server-id = 1 //指定服务器的IDlog-bin = mysql-bin //开启二进制日志binlog-ignore = mysql //忽略mysql和information_schema 数据库binlog-ignore = information_schemabinlog-do-db = blog    //同步数据库，默认同步所有数据库3)查看master状态。mysql> show master status;+---------------+----------+--------------+--------------------------+| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB         |+---------------+----------+--------------+--------------------------+| binlog.022343 |   339244 | blog         | mysql,information_schema |+---------------+----------+--------------+--------------------------+1 row in set (0.00 sec)4)在slave端创建数据库blog,导出master端的blog库，导入到此库，并修改mysql主配置文件my.cnf server-id = 2 重启mysql数据库。mysql> change master to    -> master_host='192.168.1.243',    -> master_port=3306,    -> master_user='rep',    -> master_password='rep123',    -> master_log_file='binlog.022343',    -> master_log_pos=339244;5)mysql主从同步测试，show slave status\G;能看到Slave_IO_Running和Slave_SQL_Running都为YES即可。mysql> show slave status\G;*************************** 1. row ***************************             Slave_IO_State: Waiting for master to send event                Master_Host: 192.168.1.243                Master_User: rep                Master_Port: 3306              Connect_Retry: 60            Master_Log_File: binlog.022343        Read_Master_Log_Pos: 339110             Relay_Log_File: relaylog.005481              Relay_Log_Pos: 339244      Relay_Master_Log_File: binlog.022343           Slave_IO_Running: Yes          Slave_SQL_Running: Yes            Replicate_Do_DB:        Replicate_Ignore_DB: mysql,test,information_schema         Replicate_Do_Table:     Replicate_Ignore_Table:    Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:                 Last_Errno: 0                 Last_Error:               Skip_Counter: 0        Exec_Master_Log_Pos: 339110            Relay_Log_Space: 339244            Until_Condition: None             Until_Log_File:              Until_Log_Pos: 0         Master_SSL_Allowed: No         Master_SSL_CA_File:         Master_SSL_CA_Path:            Master_SSL_Cert:          Master_SSL_Cipher:             Master_SSL_Key:      Seconds_Behind_Master: 01 row in set (0.00 sec)

2.Haproxy安装及其配置，master和backup安装配置都是完全一样的。

wget http://haproxy.1wt.eu/download/1.4/src/haproxy-1.4.24.tar.gztar -zxvf haproxy-1.4.24.tar.gzcd haproxy-1.4.24make TARGET=linux26 PREFIX=/usr/local/haproxymake install PREFIX=/usr/local/haproxycd /usr/local/haproxymkdir conf logs   //在此目录下面建立conf，logs目录分别存放HAproxy的配置文件，PID文件和日志文件。vim conf/haproxy.confglobal        maxconn 50000        chroot /usr/local/haproxy        uid 99        gid 99        daemon        quiet        nbproc  2        pidfile /usr/local/haproxy/logs/haproxy.pid        #debugdefaults        log     global        mode    http        option  httplog   #每次请求完毕后主动关闭http通道        option  dontlognull #不记录健康检查的日志信息        option forwardfor        option redispatch        option abortonclose        retries 3        log 127.0.0.1 local3        maxconn 20000        contimeout      5000        clitimeout      50000        srvtimeout      50000listen 192.168.1.236       bind *:80       mode http       stats uri /admin                    #后端服务器状态查看地址       stats auth admin:admin             #状态查看页面登陆帐号密码       balance source   #调度算法，source是和nginx的ip_hash同理，解决session问题       option httpclose       option forwardforserver web1 192.168.1.248:80 weight 5 check inter 2000 rise 2 fall 5server web2 192.168.1.249:8080 weight 5 check inter 2000 rise 2 fall 5#启动Haproxy服务/usr/local/haproxy/sbin/haproxy -f haproxy.conf#haproxy启动脚本#!/bin/bashBASE_DIR="/usr/local/haproxy"ARGV="$@"start(){echo "START HAPoxy SERVERS"$BASE_DIR/sbin/haproxy -f $BASE_DIR/conf/haproxy.conf}stop(){echo "STOP HAPoxy Listen"kill -TTOU $(cat $BASE_DIR/logs/haproxy.pid)echo "STOP HAPoxy process"kill -USR1 $(cat $BASE_DIR/logs/haproxy.pid)}case $ARGV instart)startERROR=$?;;stop)stopERROR=$?;;restart)stopstartERROR=$?;;*)echo "hactl.sh [start|restart|stop]"esacexit $ERROR

3.Haproxy开启系统日志支持。

vim /etc/syslog.conf#添加：local3.*        /var/log/haproxy.loglocal0.*        /var/log/haproxy.logvim /etc/sysconfig/syslog#修改：SYSLOGD_OPTIONS="-r -m 0"#重新启动syslog服务/etc/init.d/syslog restart

4.Keepalived的安装配置。

wget http://www.keepalived.org/software/keepalived-1.2.5.tar.gzln -s /usr/src/kernels/2.6.18-164.el5-x86_64/ /usr/src/linuxtar -zxvf keepalived-1.2.5.tar.gzcd keepalived-1.2.5./configure --prefix=/usr/local/keepalivedmake && make installcp keepalived/etc/init.d/keepalived.rh.init /etc/init.d/keepalivedchmod +x /etc/init.d/keepalivedcp keepalived/etc/init.d/keepalived.sysconfig /etc/sysconfig/keepalivedchkconfig --add keepalivedchkconfig --level 35 keepalived oncp /usr/local/keepalived/sbin/keepalived /bin/mkdir -p /etc/keepalivedcp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/#Haproxy master配置文件vim /etc/keepalived/keepalived.conf! Configuration File for keepalivedglobal_defs {    notification_email {    shifeng_zhang88@163.com    }    notification_email_from shifeng_zhang88@163.com    smtp_server smtp.163.com    smtp_connect_timeout 30    router_id LVS_Master}vrrp_script chk_http_port {    script  "/etc/keepalived/check_haproxy.sh"    interval        5       #脚本执行间隔    weight         -5       #执行脚本后优先级变更：5表示优先级+5；-5则表示优先级-5}vrrp_instance VI_A {    state MASTER    interface eth0    virtual_router_id 50    priority 100    advert_int 1    authentication {        auth_type PASS        auth_pass sfzhang1109    }track_script {    chk_http_port    }    virtual_ipaddress {        192.168.1.236    #haproxy虚拟IP    }}#Haproxy backup配置文件只需改变state和priority的值state BACKUPpriority 50#启动keepalived服务/etc/init.d/keepalived start

5.编辑check_haproxy.sh脚本，需要将haproxy启动脚本放到/etc/init.d/里面。

vim /etc/keepalived/check_haproxy.sh#!/bin/bashA=`ps -C haproxy --no-header |wc -l`if [ $A -eq 0 ];then/etc/init.d/haproxy restartecho "Start haproxy" &> /dev/nullsleep 3if [ `ps -C haproxy --no-header |wc -l` -eq 0 ];then/etc/init.d/keepalived stopecho "Stop keepalived" &> /dev/nullfifi#chomd +x /etc/keepalived/check_haproxy.sh

6.Haproxy+Keepalived高可用性测试。

   测试方法：当后端的WEB服务器down机时，haproxy会自动检测到并把请求发送到正常的服务器上面,通过haproxy监控页面（http://192.168.1.235/admin）可以查看。

    说明：（希望大家提出宝贵的意见）

      1）拓扑图只是项目的一个雏形，后期还要添加监控服务器和邮件等服务器。

      2）Mysql主库负责用户数据的写入，slave负责用户数据的读取和数据的备份等，除了要监控mysql主从外还要监控Seconds_Behind_Master选项，以免产生主从数据不同步或者延时。

      3）当WEB的负载很大的时候，可以在haproxy添加多台物理机即可，并考虑把项目的图片分离出来做成单独的图片服务器。