02. Nginx Basic Usuage

Folder Structure

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How to startup

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Nginx & Http

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Virtual Machine

server_name to match the domain name.
server_name: the domain name of a server
Matching rules: (Please be careful of the order for domain matching)

1. Name matching
   1. server_name www.why.com v.why.com;
2. Wildcard matching
   1. server_name *.why.com;
   2. server_name www.why.*;
3. Regex Matching:
   server_name ~^[0-9]+\.why\.com$;

Reverse Proxy

Tunnel Model
LVS(DR) Model

using proxy_pass to config reverse proxy.
proxy_pass http://www.why.com;

Config A group of server

1. Using polling
   drawbacks:
2. can not keep session

upstream httpds {
  server 192.168.1.101:80;
  server 192.168.1.102:80;
}

server {
  listen 80;
  server_name *.why.com;
  location /{
    proxy_pass http://httpds;
  }
}

2. Using weighting

upstream httpds {
  server 192.168.1.101:80 weight=8;
  server 192.168.1.102:80 weight=1;
}

3. Using down
   sleep the machine

upstream httpds {
  server 192.168.1.101:80 weight=8 done;
  server 192.168.1.102:80 weight=1;
}

4. Using backup
   the backup machine can be used when no others are available.

upstream httpds {
  server 192.168.1.101:80 weight=8;
  server 192.168.1.102:80 weight=1 backup;
}

5. Using ip_hash: according to the ip of client to redirect requests to the same server
6. Using least_conn: the least connnection with server
7. Using fair: redirect requests based on the response time of back server.
   1. For accessing resource locate on different server.
8. Using url_hash: According to the url to redirect requests.

Separation of static and dynamic

Only suits for small website

server {
  listen 80;
  server why.com
  location / {
    proxy_pass http://127.0.0.1:8080;
  }
  location ~*/(js|img|css){
    root html;
  }
}

URLRewrite

server {
  listen 80;
  server why.com
  location / {
    rewrite ^(\d+).html$ index.jsp?pageNum=$1 break;
    rewrite ^([0-9]+).html$ index.jsp?pageNum=$1 break;
    proxy_pass http://127.0.0.1:8080;
  }
}

Info

last: when match with the current pattern, will continue to find new location URI
break: when matching with the current pattern, will stop
redirect: # return 302 redirect, the browser will display the redirect URL
permanent: # return 301 permanent redirect, the browser will display the redirect URL

Difference between redirect and permanent: It's the same for users, but different for web crawler.

How to make a high availability

Using [keepalived](https://www.keepalived.org/download.html) to drift the virtual IP address.

Master Node

!Configuration File for keepalived

global_defs {
  router_id lb111
}

vrrp_instance why{
  state MASTER
  interface eth0
  virtual_router_id 51
  priority 100
  advert_int 1
  authentication {
    auth_type PASS
    auth_pass 1111
  }
  virtual_ipaddress {
    192.168.1.200
  }
}

Backup Node

!Configuration File for keepalived

global_defs {
  router_id lb110
}

vrrp_instance why{
  state BACKUP
  interface eth0
  virtual_router_id 51
  priority 50
  advert_int 1
  authentication {
    auth_type PASS
    auth_pass 1111
  }
  virtual_ipaddress {
    192.168.1.200
  }
}

The keepalived detect whether the instace is alived to work.