Nginx

nginx serves as:

HTTP server
HTTPS server
Reverse Proxy
Load Balancer
Mail Proxy

Basic HTTP Features

Serving static and index files, and autoindexing; open file descriptor cache;
Accelerated reverse proxying with caching; simple load balancing and fault tolerance;
Accelerated support with caching of remote FastCGI servers; simple load balancing and fault tolerance;
Modular architecture. Filters include gzipping, byte ranges, chunked responses, XSLT, SSI, and image resizing filter.
- Multiple SSI inclusions within a single page can be processed in parallel if they are handled by FastCGI or proxied servers.
SSL and TLS SNI support.

Additional HTTP Features

Name-based and IP-based virtual servers;
Keep-alive and pipelined connections support;
Flexible configuration;
Reconfiguration and online upgrade without interruption of the client processing;
Access log formats, bufferred log writing, and quick log rotation;
3xx-5xx error codes redirection;
The rewrite module;
Access control based on client IP address and HTTP Basic authentication;
The PUT, DELETE, MKCOL, COPY and MOVE methods;
FLV streaming;
Speed limitation;
Limitation of simultaneous connections or requests from one address.
Embedded Perl

Mail Proxy Server Features

User redirection to IMAP/POP3 backend using an external HTTP authentication server;
User authentication using an external HTTP authentication server and connection redirection to internal SMTP backend;
Authentication methods:
- POP3: USER/PASS, APOP, AUTH LOGIN/PLAIN/CRAM-MD5;
- IMAP: LOGIN, AUTH LOGIN/PLAIN/CRAM-MD5;
- SMTP: AUTH LOGIN/PLAIN/CRAM-MD5;
SSL support;
STARTTLS and STLS support.

Architecture and Scalability

One master process and several workers processes. The workers run as unprivileged user;
The notification methods:
- kqueue (FreeBSD 4.1+)
  - The support of the various kqueue features including:
    - EV_CLEAR
    - EV_DISABLE (to disable event temporalily)
    - NOTE_LOWAT
    - EV_EOF
- epoll (Linux 2.6+)
- rt signals (Linux 2.2.19+)
- /dev/poll (Solaris 7 11/99+)
- event ports (Solaris 10)
- select, and poll;
- sendfile (FreeBSD 3.1+, Linux 2.2+, Mac OS X 10.5)
- sendfile64 (Linux 2.4.21+)
- sendfilev (Solaris 8 7/01+)
- File AIO (FreeBSD 4.3+, Linux 2.6.22+);
Accept-filters (FreeBSD 4.1+) and TCP_DEFER_ACCEPT (Linux 2.4+) support;
10,000 inactive HTTP keep-alive connections take about 2.5M memory;
Data copy operations are kept to a minimum.

Nginx Configuration Directives

Nginx Configuration Reference

Directive Index

error_log

The error log for the domain, this is set by default the same on all vhosts(/var/log/nginx/vhost-error_log).

 error_log file [ debug | info | notice | warn | error | crit ]

Disabling error logging

 error_log /dev/null crit;

access_log

 access_log path [format [buffer=size]]|off

 
  access_log /usr/local/apache/domlogs/YOURDOMAIN.COM-bytes_log bytes_log;
  access_log /usr/local/apache/domlogs/YOURDOMAIN.COM combined;

proxy_pass

This directive sets the address of the proxied server and the URI to which location will be mapped.

Target address may be given as Hostname|IP:PORT|Backend, for example:

 
  proxy_pass http://ws2:example.com:8081/;
  proxy_pass http://10.0.1.1:8080/;
  proxy_pass backend;

root

This is equivalent to DocumentRoot in Apache. Used in location blocks to serve matched content from this document root.

 root /srv/web/example.com/htdocs/;

Location Block

 location [=|~|~*|^~|@] /uri/ { ... };

Case-Insensitive

 location ~* /images/ { ... };

Case-Sensitive

 location ~ /images/ { ... };

Match "/"

 location = / { ... };

Match everything

 location / { ... };

Regex Matching

 location ~* \.(bmp|gif|jpe?g|png|tiff)$ {
   root /srv/web/cdn.example.com/images/;
 };
 location ~* \.(swf|(j|cs)s)$ {
   root /srv/web/cdn.example.com/lib/;
 };

VirtualHost Equivalents

 
  server {
    error_log  /var/log/nginx/error_log warn;
    access_log /usr/local/apache/domlogs/YOURDOMAIN.COM.com-bytes_log bytes_log;
    access_log /usr/local/apache/domlogs/YOURDOMAIN.COM combined;
 
    listen    80;
    server_name  YOURDOMAIN.COM WWW.YOURDOMAIN.COM;
 
    # Redirect media file or static content extensions to a specific document_root 
    location ~* \.(gif|jpg|jpeg|png|wmv|avi|mpg|mpeg|mp4|htm|html|js|css)$ {
     root   /home/user/public_html;
    }
 
    location / {
     client_max_body_size    10m;
     client_body_buffer_size 128k;
 
     proxy_send_timeout   90;
     proxy_read_timeout   90;
 
     proxy_buffer_size    4k;
 
     # fixes upstream response buffering warning
     proxy_buffers     16 32k;
 
     proxy_busy_buffers_size 64k;
     proxy_temp_file_write_size 64k;
 
     proxy_connect_timeout 30s;
 
     proxy_redirect  http://www.YOURDOMAIN.COM:8081   http://www.YOURDOMAIN.COM;
     proxy_redirect  http://YOURDOMAIN.COM:8081   http://YOURDOMAIN.COM;
 
     proxy_pass   http://IP_ADDRESS:8081/;
 
     proxy_set_header   Host   $host;
     proxy_set_header   X-Real-IP  $remote_addr;
     proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
    }
  }

NGINX & CloudFlare

HttpRealIpModule

http://wiki.nginx.org/NginxHttpRealIpModule

 
  set_real_ip_from   204.93.240.0/24;
  set_real_ip_from   204.93.177.0/24;
  set_real_ip_from   199.27.128.0/21;
  set_real_ip_from   173.245.48.0/20;
  set_real_ip_from   103.22.200.0/22;
  set_real_ip_from   141.101.64.0/18;
  real_ip_header     CF-Connecting-IP;

Troubleshooting

.xml ISE 500

Remove XML being handled by nginx if the back end of the customer's site uses xml files for configurations.

Status Page

Requires --with-http_stub_status_module flag at compile time.

 
 server {
   listen    80;
   server_name  0.0.0.0;
 
   location /nginx_status {
     stub_status on;
     access_log   off;
     allow MANAGEMENT_IP;
   }
 }

Then restart NGINX with:

 nginx -s reload

MANAGEMENT_IP then becomes authorized to view http://YOURDOMAIN.COM/nginx_status

Status Page Details

Active connections: 17802
server accepts handled requests
 219633918 2198306548 21970465
Reading: 195 Writing: 1979 Waiting: 850

Status Stub Variables

Key	Value
active connections	# of open connections +backends
reading	# of sockets currently reading request headers
writing	# of sockets currently reading request body, processing a request, or in response phase
waiting	# of active keep-alive sockets

Reverse Proxy & Load Balancer

Upstream (proxy/load_balancer)

Context: http

http://wiki.nginx.org/HttpUpstreamModule

 
upstream backend  {
 
  # ip_hash; # remove first "#" for upstream to >1 servers
 
  # weighted to decrease failure tolerance and spray traffic using escalating fault tolerance
  server 172.16.10.4:8080 weight=5 max_fails=3 fail_timeout=30;
  server 172.16.10.3:8080 weight=4 max_fails=5 fail_timeout=45;
  server 172.16.10.2:8080 weight=3 max_fails=7 fail_timeout=60;
  server 172.16.10.1:8080 weight=2 max_fails=9 fail_timeout=90;
 
}
 
server {
  location / {
    proxy_pass  http://backend;
  }
}

LimitZone (DoS Prevention)