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（由於LVS采用的是同步請求轉發策略而Nginx采用的是異步轉發策略，結合兩者的缺點:作為負載均衡服務器的Nginx和LVS處理相同的請求時，所有的請求和響應流量都會經過Nginx服務器，但是使用LVS時，僅請求流量經過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，但是僅僅使用LVS作為負載均衡使用時，一旦後端接收到請求的服務器出了問題，那麽這次請求就失敗了，如果在LVS後端添加一層Nginx代理群，結合兩者的優勢，就避免以上的情況出現）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也重做一遍）
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
}
}
}
啟動服務：
service keepalived start
chkconfig keepalived on
配置Nginx-M（Nginx-S也重做一遍）
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 {
[email protected]
[email protected]
}
notification_email_from [email protected]
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 {
[email protected]
[email protected]
}
notification_email_from [email protected]
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服務器都需要）
#!/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
開啟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））
本文出自 “Change life Start fresh.” 博客，請務必保留此出處http://ahcwy.blog.51cto.com/9853317/1940296
LVS(負載均衡)+keepalived（HA）＋Nginx（反向代理）+Web（動靜態網站服務器）