Tuesday, June 15, 2010

Common nginx configuration options

Google reveals a wealth of tutorials and sample nginx config files, but in any case here are some configuration tips that have been helpful to me.

Include files

Don't be shy in splitting up your main nginx.conf file into several smaller files. Your co-workers will be grateful. A structure that has been working for me is to have one file where I define my upstream pools, one file where I define locations that point to upstream pools, and one file where I define servers that handle those locations.

Examples:

upstreams.conf

upstream cluster1 {
fair;
server app01:7060;
server app01:7061;
server app02:7060;
server app02:7061;
}

upstream cluster2 {
fair;
server app01:7071;
server app01:7072;
server app02:7071;
server app02:7072;
}

locations.conf


location / {
root /var/www;
include cache-control.conf;
index index.html index.htm;
}

location /services/service1 {
proxy_pass_header Server;
proxy_set_header Host $http_host;
proxy_redirect off;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Scheme $scheme;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

add_header Pragma "no-cache";


proxy_pass http://cluster1/;
}

location /services/service2 {
proxy_pass_header Server;
proxy_set_header Host $http_host;
proxy_redirect off;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Scheme $scheme;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

add_header Pragma "no-cache";

proxy_pass http://cluster2/service2;
}

servers.conf

server {
listen 80;
include locations.conf;
}

At this point, your nginx.conf looks very clean and simple (you can still split it into more include files, by separating for example the gzip configuration options into their own file etc.)

nginx.conf

worker_processes 4;
worker_rlimit_nofile 10240;

events {
worker_connections 10240;
use epoll;
}

http {
include upstreams.conf;

include mime.types;
default_type application/octet-stream;

log_format custom '$remote_addr - $remote_user [$time_local] '
'"$request" $status $bytes_sent '
'"$http_referer" "$http_user_agent" "$http_x_forwarded_for" $request_time';

access_log /usr/local/nginx/logs/access.log custom;

proxy_buffering off;
sendfile on;
tcp_nopush on;
tcp_nodelay on;

gzip on;
gzip_min_length 10240;
gzip_proxied expired no-cache no-store private auth;
gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml application/xml+rss image/svg+xml application/x-font-ttf application/vnd.ms-fontobject;
gzip_disable "MSIE [1-6]\.";

# proxy cache config
proxy_cache_path /mnt/nginx_cache levels=1:2
keys_zone=one:10m
inactive=7d max_size=10g;
proxy_temp_path /var/tmp/nginx_temp;

proxy_next_upstream error;

include servers.conf;
}

This nginx.conf file is fairly vanilla in terms of the configuration options I used, but it's worth pointing some of them out.

Multiple worker processes

This is useful when you're running nginx on a multi-core box. Example:

worker_processes 4;

Increased number of file descriptors

This is useful for nginx instances that get hit by very high traffic. You want to increase the maximum number of file descriptors that nginx can use (the default on most Unix systems is 1024; run 'ulimit -n' to see the value on your system). Example:

worker_rlimit_nofile 10240;


Custom logging

See the log_format and access_log directives above. In particular, the "$http_x_forwarded_for" value is useful if nginx is behind another load balancer, and "$request_time" is useful to see the time taken by nginx when processing a request.

Compression

This is useful when you want to compress certain types of content sent back to the client. Examples:


gzip on;
gzip_min_length 10240;
gzip_proxied expired no-cache no-store private auth;
gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml application/xml+rss image/svg+xml application/x-font-ttf application/vnd.ms-fontobject;
gzip_disable "MSIE [1-6]\.";

Proxy options

These are options you can set per location. Examples:


proxy_pass_header Server;
proxy_set_header Host $http_host;
proxy_redirect off;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Scheme $scheme;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
add_header Pragma "no-cache";


Most of these options have to do with setting custome HTTP headers (in particular 'no-cache' in case you don't want to cache anything related to that particular location)

Proxy cache

Nginx can be used as a caching server. You need to define a proxy_cache_path and a proxy_temp_path under your http directive, then use them in the locations you want to cache.


proxy_cache_path /mnt/nginx_cache levels=1:2
keys_zone=one:10m
inactive=7d max_size=10g;
proxy_temp_path /var/tmp/nginx_temp;

In the location you want to cache, you would add something like this:

proxy_cache one;
proxy_cache_key mylocation.$request_uri;
proxy_cache_valid 200 302 304 10m;
proxy_cache_valid 301 1h;
proxy_cache_valid any 1m;
proxy_cache_use_stale error timeout invalid_header http_500 http_502 http_503 http_504 http_404;

HTTP caching options

Many times you want to cache certain types of content and not others. You can specify your caching rules in a file that you include in your root location:

location / {
root /var/www;
include cache-control.conf;

index index.html index.htm;
}

You can specify different expire headers and cache options based on the request URI. Examples (inside cache-control.conf in my case)

# default cache 1 day
expires +1d;

if ($request_uri ~* "^/services/.*$") {
expires +0d;
add_header Pragma "no-cache";
}

if ($request_uri ~* "^/(index.html)?$") {
expires +1h;
}

SSL

All you need to do here is to define another server in servers.conf, and have it include the locations you need (which can be the same ones handled by the server on port 80 for example):

server {
server_name www.example.com;
listen 443;
ssl on;
ssl_certificate /usr/local/nginx/ssl/cert.pem;
ssl_certificate_key /usr/local/nginx/ssl/cert.key;

include locations.conf;
}



4 comments:

Anonymous said...

I think it is more efficient to use "location" instead of "if"
For example:

if ($request_uri ~* "^/services/.*$") {
expires +0d;
add_header Pragma "no-cache";
}
is the same as

location ^~ /services/ {
expires +0d;
add_header Pragma "no-cache";
}

peterbe said...

One very useful trick in terms of logging is to switch it off for certain "boring" resources like static files. Example::


location = /robots.txt {
root /bla/bla;
expires 8d;
access_log off;
}

Grig Gheorghiu said...

Anonymous and Peter -- thanks a lot for your tips!

nagaraj said...

Thanks for the excellent post.I had been struggling with an issue while trying to setup nginx as reverse proxy to hudson - http://forum.nginx.org/read.php?2,125909, and your article provided the solution. I just had to add the 'add_header Pragma "no-cache"' option to make it work.

Thanks again !!