Nginx provides Web services and enables load balancing

############# #nginx直接作为web服务站点 ###########
Background: Set up two Web service sites for a single server
1)
MKDIR/WEB1/WEB2 # #建立二根个目录
Cd/web1
Vim index.html
www.web1.org # #随便写东西

Cd/web2
Vim index.html
www.web2.org # #随便写东西和第一个不一样就行
2)
vim/usr/local/nginx/conf/nginx.conf # #添加以下参数

server {
Listen 80;
server_name www.web1.org;
Location/{
Root/web1;
Index index.html;

}
}
server {
Listen 80;
server_name www.web2.org;
Location/{
ROOT/WEB2;
Index index.html;
}
}
3) Check and load the service
NGINX-T # #查看nginx服务是否配置成功
Nginx-s Reload # #重新加载nginx服务
4)
Vim/etc/hosts Write on IP parsing
172.25.8.1 server1.example.com www.web1.org www.web2.org
5) Testing
Curl www.web1.org
Return content: www.web1.org
Curl www.web2.org
Return content: www.web2.com
or open a browser to access: www.web1.org www.web2.org
(in which machine on which machine/etc/hosts add parsing 172.25.8.1 www.web1.org www.web2.org)


########## #nginx作为反向代理服务器实现负载均衡 #############
Nginx is used as a reverse proxy server, placed before two Apache, as a user access to the portal

Background: Server1 installed Nginx as a proxy server, Server2, 3 installation httpd services, providing real service
1) on the Server1
HTTP {
Upstream Web {# #在http段添加, the web is the name
Server 172.25.8.2:80;
Server 172.25.8.3:80;
}

vim/usr/local/lnmp/nginx/conf/nginx.conf Add the following
Note #root/web1; # #在server段注释
#index index.html;
Proxy_pass http://web; # #表示将所有请求转发到web服务器组中某一服务器上, this is the Load Balancer module, which is added in the server segment

2) Check and load the service
NGINX-T # #查看nginx服务是否配置成功
Nginx-s Reload # #重新加载nginx服务

3) in Server2, Server3
/ETC/INIT.D/HTTPD Start # #打开server2 Server3 's httpd service
Vim/var/www/html/index.html # #编辑文件
www.web2.org # #写入内容
Vim/var/www/html/index.html # #编辑文件
www.web3.org # #写入内容

4) Testing
Vim/etc/hosts
172.25.8.1 Web # #添加解析
Curl Http://web

/ETC/INIT.D/HTTPD # #关闭server2的httpd, Server3 can provide services

############# #Nginx的负载均衡策略 (only the first three types) ##############

Nginx's upstream currently supports 5 ways to allocate
1. Polling (default)
Each request is assigned to a different back-end server in chronological order, and can be automatically rejected if the backend server is down.
Upstream Web {
Server 192.168.0.14;
Server 192.168.0.15;
}

2, Weight
Specifies the polling probability, proportional to the weight and access ratios, for situations where the performance of the backend server is uneven.
Upstream Web {
Server 192.168.0.14 weight=5; # #数字大权重大
Server 192.168.0.15 weight=1;
}

3, Ip_hash
Each request is allocated according to the hash result of the access IP, so that each visitor has fixed access to a back-end server that resolves the session issue.
Upstream web{
Ip_hash;
Server 192.168.0.14:88;
Server 192.168.0.15:80;
}

4. Fair (third party)
The response time of the back-end server is allocated to the request, and the response time is short of priority allocation.
Upstream Web {
server Server1;
Server Server2;
Fair
}

5. Url_hash (Third Party)
Assign requests by the hash result of the access URL so that each URL is directed to the same back-end server, which is more efficient when the backend server is cached.
Upstream Westos {
Server squid1:3128;
Server squid2:3128;
Hash $request _uri;
Hash_method CRC32;
}

In servers that need to use load balancing, add
Proxy_pass http://web;
Upstream backserver{

Ip_hash;
Server 127.0.0.1:9090 down; (down indicates that the current server is temporarily not participating in the load)
Server 127.0.0.1:8080 weight=2; (weight defaults to 1.weight, the greater the load weight)
Server 127.0.0.1:6060;
Server 127.0.0.1:7070 backup; (When all other non-backup machines are down or busy, request the backup machine)
}

Max_fails: The number of times that a request failed is allowed defaults to 1. Returns the error defined by the Proxy_next_upstream module when the maximum number of times is exceeded
Fail_timeout:max_fails times after a failure, the time of the pause

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Nginx provides Web services and enables load balancing