Nginx负载均衡组件模块
实现Nginx负载均衡的组件主要有两个：
ngx_http_proxy_module proxy代理模块，用于把请求后抛给服务器节点或upstream服务器池
ngx_http_upstream_module 负载均衡模块，可以实现网站的负载均衡功能及节点的健康检查
Nginx反向代理负载均衡安装
安装Nginx软件：
1、安装依赖软件包
yum install -y openssl openssl-devel pcre pcre-devel #安装
rpm -qa openssl openssl-devel pcre pcre-devel #查看
2、安装Nginx软件包
useradd ceshi
mkdir /home/ceshi/tools
cd /home/ceshi/tools/
useradd -s /sbin/nologin -M nginx
wget -q http://mirrors.sohu.com/nginx/nginx-1.6.3.tar.gz
tar xf nginx-1.6.3.tar.gz
cd nginx-1.6.3
./configure --user=nginx --group=nginx --prefix=/application/nginx-1.6.3 --with-http_ssl_module --with-http_stub_status_module
make
make install
ln -s /application/nginx-1.6.3/ /application/nginx
cd /application/nginx/conf/
egrep -v "#|^$" nginx.conf.default
egrep -v "#|^$" nginx.conf.default >nginx.conf
vim nginx.conf
添加以下内容：
upstream www_server_pools {
server 10.0.0.7:80 weight=1;
server 10.0.0.8:80 weight=1;
}
proxy_pass http://www_server_pools;
编辑后的配置文件
worker_processes 1;
events {
worker_connections 1024;
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
upstream www_server_pools {
server 10.0.0.7:80 weight=1;
server 10.0.0.8:80 weight=1;
}
server {
listen 80;
server_name localhost;
location / {
root html;
index index.html index.htm;
proxy_pass http://www_server_pools;
}
}
}
/application/nginx/sbin/nginx -t
/application/nginx/sbin/nginx -s reload
测试一：
反向代理服务器lb01：
[root@lb01 ~]# vim /application/nginx/conf/nginx.conf
server_name www.etiantian.org; #在server标签中添加网址做测试
[root@lb01 ~]# /application/nginx/sbin/nginx -s reload
客户端测试lb02：
[root@lb02 ~]# vim /etc/hosts
172.16.1.5 lb01 www.etiantian.org etiantian.org bbs.eti
antian.org blog.etiantian.org
[root@lb02 ~]# curl www.etiantian.org
www
[root@lb02 ~]# for n in `seq 100`;do curl www.etiantian.org;sleep 1;done #测试负载均衡
apache www
www
apache www
www
[root@lb02 ~]# for n in `seq 100`;do curl www.etiantian.org;sleep 1;done #当其中一台网页服务器宕机
www
apache www
www
apache www
apache www
测试二：
反向代理服务器lb01：
[root@lb01 ~]# vim /application/nginx/conf/nginx.conf
server_name www.etiantian.org; 修改为 server_name bbs.etiantian.org;
[root@lb01 ~]# /application/nginx/sbin/nginx -s reload
客户端测试lb02：
[root@lb02 ~]# for n in `seq 100`;do curl bbs.etiantian.org;sleep 1;done
apache www
www
注意：还是www，因为lb请求web服务器请求报文没有host，虽然没有host，但是wab会先看请求有没有host，有host时就按host给对应的网页，没有host就会给第一个配置的网页
解决办法：
反向代理服务器lb01：
[root@lb01 ~]# vim /application/nginx/conf/nginx.conf
proxy_set_header Host $host;
[root@lb01 ~]# /application/nginx/sbin/nginx -s reload
客户端测试lb02：
[root@lb02 ~]# for n in `seq 100`;do curl bbs.etiantian.org;sleep 1;done
apache bbs
bbs
启动Nginx报错
[root@lb01 conf]# /application/nginx/sbin/nginx
nginx: [emerg] getpwnam("nginx") failed
原因：没有安装nginx用户导致的无法启动
[root@lb01 conf]# useradd -s /sbin/nologin -M nginx
[root@lb01 conf]# id nginx
uid=501(nginx) gid=501(nginx) groups=501(nginx)
[root@lb01 conf]# /application/nginx/sbin/nginx
[root@lb01 conf]# lsof -i :80
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
nginx 3710 root 6u IPv4 19718 0t0 TCP *:http (LISTEN)
nginx 3711 nginx 6u IPv4 19718 0t0 TCP *:http (LISTEN)
客户端访问出错：
[root@lb02 ~]# curl www.etiantian.org
curl: (7) couldn't connect to host
原因：这样的错误可能是主机不可到达，或者端口不可到达。
ping OK只代表主机可以到达。
端口不可到达可能是由于HTTP 服务器未启动或者监听在其他端口入8080上了。
还有一个可能是防火墙没开放80端口的访问权限。
[root@lb01 ~]# service iptables stop
iptables: Setting chains to policy ACCEPT: filter [ OK ]
iptables: Flushing firewall rules: [ OK ]
iptables: Unloading modules: [ OK ]
[root@lb01 ~]# chkconfig iptables off
客户端访问：
[root@lb02 ~]# curl www.etiantian.org
apache www
实现负载均衡：
负载均衡服务器lb01和lb02:
vim /application/nginx/conf/nginx.conf
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
upstream server_pools {
server 10.0.0.7:80 weight=1;
server 10.0.0.8:80 weight=1;
}
server {
listen 80;
server_name bbs.etiantian.org;
location / {
proxy_pass http://server_pools;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $remote_addr;
}
}
server {
listen 80;
server_name blog.etiantian.org;
location / {
proxy_pass http://server_pools;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $remote_addr;
}
}
}
ip addr add 10.0.0.3/24 dev eth0 label eth0:0
主服务器lb01的配置
yum install keepalived -y
vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
}
notification_email_from [email protected]
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.3/24 dev eth0 label eth0:1
}
}
scp /etc/keepalived/keepalived.conf [email protected]:/etc/keepalived/
ifconfig eth0:0 down
/etc/init.d/keepalived start
ip addr|grep 10.0.0.3
从服务器lb01的配置：
yum install keepalived -y
vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
}
notification_email_from [email protected]
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL1 #DEVEL更改为DEVEL1不能和主的冲突
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 100 #150更改为100，主的要优先
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.3/24 dev eth0 label eth0:1
}
}
/application/nginx/sbin/nginx
/etc/init.d/keepalived start
ip addr|grep 10.0.0.3