LVS(負載均衡)+keepalived（HA）＋Nginx（反向代理）+Web（動靜態網站服務器）

考慮到LVS和Nginx的缺點（因爲LVS採用的是同步請求轉發策略而Nginx採用的是異步轉發策略，結合二者的缺點:做爲負載均衡服務器的Nginx和LVS處理相同的請求時，全部的請求和響應流量都會通過Nginx服務器，可是使用LVS時，僅請求流量通過LVS的網絡，響應流量由後端的服務器的網絡返回，也就是說，當後端web服務器規模較大時，Nginx的網絡帶寬就成了一個巨大的瓶頸，可是僅僅使用LVS做爲負載均衡使用時，一旦後端接收到請求的服務器出了問題，那麼此次請求就失敗了，若是在LVS後端添加一層Nginx代理羣，結合二者的優點，就避免以上的狀況出現）再結合Keepalived實現LVS和Nginx的高可用

條件：

六臺虛擬機：

兩臺LVS

兩臺Nginx

兩臺web服務器

LVS-M上面：（LVS-S也重作一遍）

優化環境（/etc/sysctl.conf）

net.ipv4.conf.all.send_redirects = 0

net.ipv4.conf.default.send_redirects = 0

net.ipv4.conf.eth0.send_redirects = 0

sysctl -p

modprobe ip_vs

yum install -y ipvsadm

設置負載調度器模式

ipvsadm -A -t 192.168.115.180:80 -s rr

ipvsadm -a -t 192.168.115.180:80 -r 192.168.115.176:80 -g（176和177分別指向兩個nginx代理服務器）

ipvsadm -a -t 192.168.115.180:80 -r 192.168.115.177:80 -g

查看：

ipvsadm -Ln

安裝keepalived

yum install -y gcc*  kernel-devel openssl-devel popt-devel

tar -xvf keepalived-1.2.7.tar.gz

./configure --prefix=/  --with-kernel-dir=/usr/src/kernels/2.6.32-131.0.15.el6.i686

make && make install

chkconfig --add keepalived

chkconfig keepalived on

配置keepalived文件（LVS-M）

global_defs {

  router_id LVS_R1

}

vrrp_instance VI_1 {

   state MASTER

interface eth0

virtual_router_id 51

   priority 100

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

       192.168.115.180

}

}

virtual_server 192.168.115.180 80 {

delay_loop 6

lb_algo rr

lb_kind DR

protocol TCP

real_server 192.168.115.176 80 {

weight 1

TCP_CHECK {

connect_port 80

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

}

real_server 192.168.115.177 80 {

weight 1

TCP_CHECK {

connect_port 80

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

}

}

配置keepalived文件（LVS-S）

! Configuration File for keepalived

global_defs {

  router_id LVS_R2

}

vrrp_instance VI_1 {

   state SLAVE

interface eth0

virtual_router_id 51

   priority 90

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

192.168.115.180

}

}

virtual_server 192.168.115.180 80 {

delay_loop 6

lb_algo rr

lb_kind DR

protocol TCP

real_server 192.168.115.176 80 {

weight 1

TCP_CHECK {

connect_port 80

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

}

real_server 192.168.115.177 80 {

weight 1

TCP_CHECK {

connect_port 80

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

}

}

啓動服務：

service keepalived start

chkconfig keepalived on

配置Nginx-M（Nginx-S也重作一遍）

安裝Nginx 和 keepalived

yum install -y pcre-devel zlib-devel

rpm -ivh nginx-1.8.1-1.el6.ngx.x86_64.rpm

keepalived的安裝參考上面

配置Nginx反向代理

配置keepalived（Nginx-M）

! Configuration File for keepalived

global_defs {

notification_email {

ops@wangshibo.cn

tech@wangshibo.cn

}

notification_email_from ops@wangshibo.cn

smtp_server 127.0.0.1

smtp_connect_timeout 30

router_id master-node

}

vrrp_script chk_http_port {

   script "/opt/chk_nginx.sh"

interval 2

weight -5

fall 2

rise 1

}

vrrp_instance VI_1 {

   state MASTER

   interface eth0

 mcast_src_ip 192.168.115.176

virtual_router_id 51

   priority 101

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

192.168.115.180

}

track_script {

chk_http_port

}

}

配置keepalived（Nginx-S）

! Configuration File for keepalived

global_defs {

notification_email {

ops@wangshibo.cn

tech@wangshibo.cn

}

notification_email_from ops@wangshibo.cn

smtp_server 127.0.0.1

smtp_connect_timeout 30

router_id master-node

}

vrrp_script chk_http_port {

   script "/opt/chk_nginx.sh"

interval 2

weight -5

fall 2

rise 1

}

vrrp_instance VI_2 {

   state SLAVE

   interface eth0

   mcast_src_ip 192.168.115.177

virtual_router_id 51

   priority 99

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

192.168.115.180

}

track_script {

chk_http_port

}

}

在/opt下面編寫腳本chk_nginx.sh（兩臺Nginx服務器都須要）

#!/bin/bash

counter=$(ps -C nginx --no-heading|wc -l)

if [ "${counter}" = "0" ]; then

service nginx restart

sleep 2

counter=$(ps -C nginx --no-heading|wc -l)

if [ "${counter}" = "0" ]; then

service keepalived stop

fi

fi

賦予權限並執行

開啓keepalived服務

瀏覽器訪問：（在LVS上面任意停掉一臺服務器看訪問是否正常（斷開網卡）、在Nginx服務器上面任意停掉一臺Nginx服務看訪問是否正常（斷開Nginx服務service nginx stop））