Keepalived+Haproxy實現高可用負載均衡

高可用負載（主備節點）部署步驟

完成下圖一個簡單的高可用負載機制：

1.拷貝keepalived-1.2.19.tar.gz至Linux的/home目錄（也可以是其它目錄）

2.解壓並安裝keepalived：

tar -zxvf keepalived-1.2.19.tar.gz
yum install popt-devel
yum -y install openssl-devel
cd keepalived-1.2.19
./configure
make && make install

這樣keepalived編譯及安裝完成！

3.拷貝並複製keepalived：

cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
mkdir /etc/keepalived
cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/
cp /usr/local/sbin/keepalived /usr/sbin/

上傳並覆蓋keepalived.conf至/etc/keepalived
備註：keepalived.conf詳見步驟4

上傳check_haproxy.sh至/etc/keepalived
備註：check_haproxy.sh配置文件內容如下：

#!/bin/bash
A=`ps -C haproxy --no-header |wc -l`
if [ $A -eq 0 ];then
/usr/local/haproxy/sbin/haproxy -f /usr/local/haproxy/cfg/haproxy.cfg
sleep 3
if [ `ps -C haproxy --no-header |wc -l` -eq 0 ];then
/etc/init.d/keepalived stop
fi
fi

4.修改keepalived.conf配置文件：

! Configuration File for keepalived

global_defs {
   notification_email {
        [e-mail]  #  修改成可用的收件人地址，可爲多個
   }
 notification_email_from [e-mail]  #  修改成可用的發件人地址
   smtp_server mail.iflytek.com  #  修改成可用的郵箱代理地址
   smtp_connect_timeout 30
   router_id keepalived
}
vrrp_script chk_http_port {
     script "/etc/keepalived/check_haproxy.sh"   #  修改成Haproxy監控腳本路徑
     interval 2   #  檢查間隔時間，單位：秒
}
vrrp_instance VI_MASTER {
    state MASTER  #  修改成MASTER，意味着該服務器爲主節點；若修改爲BACKUP，則爲備用節點，即當主機宕掉，從機接管
    interface eth0
    virtual_router_id 51
    priority 150
    nopreempt
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    track_script {
             chk_http_port
    }
    virtual_ipaddress {
        192.168.1.1  #  修改成可用的虛擬IP
    }
}

5.解壓haproxy-1.5.12並上傳至/usr/local

6.修改/usr/local/haproxy/cfg配置文件haproxy.cfg：

global
      daemon
      nbproc 1
      group nobody
      user nobody
      maxconn 102400
      ulimit-n 204821
      chroot /usr/local/haproxy

defaults
      mode tcp
      maxconn 102400
      retries 3
      option redispatch
      option abortonclose
      timeout connect 600s
      timeout client 600s
      timeout server 600s

listen interface
      bind 0.0.0.0:8001
      balance leastconn
      mode http
      server interface1 192.168.85.100:8001 weight 1 maxconn 102400 check inter 10s
      server interface2 192.168.85.101:8001 weight 1 maxconn 102400 check inter 10s

listen engine
      bind 0.0.0.0:18006
      balance leastconn
      mode tcp
      server engine1 192.168.85.100:18006 weight 1 maxconn 102400 check inter 10s
      server engine2 192.168.85.101:18006 weight 1 maxconn 102400 check inter 10s

至此完成Haproxy配置修改！

7.運行如下命令，啓動Haproxy運行：

/etc/init.d/keepalived start

8.測試：

telnet 192.168.1.1 8001
telnet 192.168.1.1 18006

依次使用虛擬IP+路由端口的形式驗證對應端口是否可用！

說明：對於從機部署，與主機部署一致。這裏說明一下：對於HA，只會使用主節點，僅當主節點掛掉，纔會切換到從節點！