Nginx负载均衡器的优点:

实现看弹性化操作的架构，压力增大的时候可以临时添加后端Web服务器；

upstream具有负载均衡能力(默认使用轮询)，可以自动判断下面的机器，并且自动踢出不能正常提供服务的机器；

Keepalvied加Nginx监测脚本可保证单个nginx负载均衡器的有效性,避免单点故障

系统

两台Nginx：

CentOS6.7 x86_64

两台Web：

Ubuntu 15.04 desktop

拓扑

IP地址

nginx(主LB):192.168.15.132

nginx(备LB):192.168.15.133

VIP地址:192.168.15.135

Real1的IP:192.168.15.128

Real2的IP:192.168.15.130

部署整个环境用到的软件为:

nginx-1.6.3.tar.gz

prce-8.38.tar.gz

zlib-1.2.8.tar.gz

①2台Web主机(Ubuntu)上部署Nginx+PHP-FPM+MySQL，此处省略。

②分别在二台Nginx负载均衡器上安装Nginx，配置

安装GCC编译器等工具：

yum install -y gcc gcc-c++ autoconf automake libtool make openssl openssl-devel

安装Nginx:

wget http://exim.mirror.fr/pcre/pcre-8.38.tar.gz

tar -zxvf pcre-8.38.tar.gz

cd pcre-8.38

./configure

make && make install

wget http://zlib.net/zlib-1.2.8.tar.gz

tar -zxvf zlib-1.2.8.tar.gz

cd zlib-1.2.8

./configure

make && make install

wget http://nginx.org/download/nginx-1.6.3.tar.gz

tar -zxvf nginx-1.6.3.tar.gz

cd nginx-1.6.3/

./configure --prefix=/usr/local/nginx

--sbin-path=/usr/local/nginx/sbin/nginx

--conf-path=/usr/local/nginx/conf/nginx.conf

--pid-path=/usr/local/nginx/logs/nginx.pid \

--with-http_ssl_module \

--with-http_stub_status_module \

--with-http_gzip_static_module \

make && make install

注：查询"./configure --help"相关模块，按需求指定启用

Nginx.conf配置文件，二个nginx负载均衡器的文件一样

user  www-data www-data;

worker_processes  1;

error_log  /usr/local/nginx/logs/error.log notice;

pid        /usr/local/nginx/logs/nginx.pid;

worker_rlimit_nofile 51200;

events {

use epoll;

worker_connections  51200;

}

http {

include      mime.types;

default_type  application/octet-stream;

log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '

'$status $body_bytes_sent "$http_referer" '

'"$http_user_agent" "$http_x_forwarded_for"';

access_log  logs/access.log  main;

server_names_hash_bucket_size 128;

client_header_buffer_size 32k;

large_client_header_buffers 4 32k;

client_max_body_size 8m;

sendfile        on;

tcp_nopush    on;

server_tokens off;

keepalive_timeout  60;

fastcgi_connect_timeout 300;

fastcgi_send_timeout 300;

fastcgi_read_timeout 300;

fastcgi_buffer_size 64k;

fastcgi_buffers 4 64k;

fastcgi_busy_buffers_size 128k;

fastcgi_temp_file_write_size 128k;

gzip  on;

upstream backend

{

server 192.168.15.128;

server 192.168.15.130;

}

server {

listen      80;

server_name  192.168.15.135;

location / {

root  html;

index  index.php index.html index.htm;

proxy_redirect off;

proxy_set_header Host $host;

proxy_set_header X-Real-IP $remote_addr;

#后端的Web服务器可以通过X-Forwarded-For获取用户真实IP

proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

proxy_pass http://backend;

}

error_page  500 502 503 504  /50x.html;

location = /50x.html {

root  html;

}

location /nginx_status {

stub_status on;

auth_basic "NginxStatus";

auth_basic_user_file /usr/local/nginx/htpasswd;

#allow 127.0.0.1;

#deny all;

}

location ~* \.(ini|docx|txt|doc|pdf)$ {

#禁止访问文档性文件

root /usr/share/nginx/html;

deny all;

}

location ~ .*\.(gif|jpg|jpeg|png|bmp|swf|js|html|htm|css)$ {

root /home/image;

proxy_store on;

proxy_store_access user:rw group:rw all:rw;

proxy_temp_path /home/image;

if ( !-e $request_filename) {

proxy_pass  http://backend;

}

}

}

}

③在二台Nginx上安装及配置keepalived：

wget http://www.keepalived.org/software/keepalived-1.2.15.tar.gz

tar -zxvf keepalived-1.2.15.tar.gz

cd keepalived-1.2.15

./configure --sysconf=/etc/  --with-kernel-dir=/usr/src/kernels/2.6.32-573.8.1.el6.x86_64

make && make install

ln -s /usr/local/sbin/keepalived  /sbin/

#这一步很重要，不执行ln -s会报错“Starting keepalived: /bin/bash: keepalived: command not found”

service keepalived start

二台Nginx上keepalived.conf配置文件如下，配置完成后分别service keepalived start启动｡检验keepalived配置是否成功

主：

global_defs {

notification_email {

[email protected]

}

notification_email_from keepalived@localhost

smtp_server 127.0.0.1

smtp_connect_timeout 30

router_id LVS_MASTER

}

vrrp_script chk_http_port {

script "/usr/local/src/check_nginx_pid.sh"

interval 2                          #(检测脚本执行的间隔)

weight 2

}

vrrp_instance VI_1 {

state MASTER

interface bond0

virtual_router_id 51

priority 100

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

track_script {

chk_http_port            #(调用检测脚本)

}

virtual_ipaddress {

192.168.15.135

}

}

备：

global_defs {

notification_email {

[email protected]

}

notification_email_from keepalived@localhost

smtp_server 127.0.0.1

smtp_connect_timeout 30

router_id LVS_BACKUP

}

vrrp_script chk_http_port {

script "/usr/local/src/check_nginx_pid.sh"

interval 2                          #(检测脚本执行的间隔)

weight 2

}

vrrp_instance VI_1 {

state BACKUP

interface bond0

virtual_router_id 51

priority 66

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

track_script {

chk_http_port            #(调用检测脚本)

}

virtual_ipaddress {

192.168.15.135

}

}

以下是针对nginx状态进行检测的脚本，第一次nginx服务死掉时，会重新启动，如果Nginx服务无法正常启动，则杀掉keepalived进程

vim  /usr/local/src/check_nginx_pid.sh

#!/bin/bash

A=`ps -C nginx --no-header |wc -l`

if [ $A -eq 0 ];then

/usr/local/nginx/sbin/nginx

if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then

killall keepalived

fi

fi

Ok，开始nginx负载均衡测试，停掉其中一台的任何服务，不影响整个系统的运作｡

注：两台LBServer也可分别添加一个VIP①②(Keepalived心跳监控，服务不可用或者宕机，VIP①被备LBServer接管)，外部使用智能DNS轮询两个VIP①②，提高硬件资源利用率。

更多Nginx相关教程见以下内容：

Nginx 的详细介绍：请点这里

Nginx 的下载地址：请点这里