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Nginx - Tips and Tricks.
1. Nginx - Tips & Tricks
#rootconf
May 2012
@tuxtoti
2. /me
Builds scalable systems for ADIQUITY
Works with web servers/load balancers
Identify bottlenecks in the architecture.
Responsible for smooth serving of Mobile
Ads.
3. Nginx - History
circa 2002. Igor Sysoev. Russian dev.
writes mod_accel. Realizes the Apache’s low
scalability.
2004 - powers rambler.ru. Initial public
version released.
was built to address the C10K problem
Now after ~10 yrs its Nginx Inc.
4. Nginx - C10K problem
To serve concurrent 10K connections
Why? I/O is the bottleneck. A thread per
connection model fails. #apachefail
select() vs epoll()
http://www.kegel.com/c10k.html
5. Nginx - Killer Features
L7 Load Balancer/Reverse proxy
Embedded perl interpreter
On the fly binary upgrade.
Awesome PCRE support. Useful for rewriting
URLs.
NGINX - Ultra-fast, Light weight, low
memory footprint, feature rich
6. Nginx - Config Contexts
http - The main scope . Typically configs set
here will reflect everywhere.
server - The to run multiple servers virtually
on different ports or with different server
names.
location - Defines the scope for a URI.
upstream - Config scope for a set of
upstream/backend servers.
7. Nginx - Directives
worker_processes, worker_connections,
worker_rlimit_nofile - Configure your setup
to the amount of traffic you expect to
receive.
Number of connections =
worker_processes*worker_connections
keepalive_requests, keepalive_timeout -
Configure based on your concurrency and
throughput.
8. Nginx - Directives
upstream - Set up a list of backends for load
balancing. W/ rr and wrr it becomes very
powerful. max_fails & fail_timeout - to
consider a backend inoperative.
upstream backend {
server 192.168.1.1;
server 192.168.1.5:8080;
server 192.168.1.13 weight=3;
server 192.168.1.16 max_fails=3 fail_timeout=10s;
keepalive 2048; #nginx > 1.1.4
}
server {
location / {
proxy_pass http://backend;
}
}
9. Nginx - Directives
rr vs fair - Send the request to the least
busy backend server. #Available as a third
party module
upstream backend {
fair;
server 192.168.1.2;
server 192.168.1.3;
}
fair - knows how many requests each
backend is processing.
no_rr
10. Nginx - Directives
proxy_next_upstream - To proceed or to not
proceed?
location ~ ^/(app) {
proxy_read_timeout 12;
proxy_set_header X-Feature-Foo “1”;
proxy_pass http://test_backend;
proxy_next_upstream error;
}
Takes values: error, timeout, invalid_header,
http_*, off
11. Nginx - Directives
add_header - Add custom headers to the
response. #USE - Debug to find out the
backend server / cache control headers.
add_header Cache-Control private;
proxy_set_header - Add custom headers to
control your backends. #USE - for enabling/
disabling features in your backend.
12. Nginx - Directives
empty_gif - Serves a 1x1 transparent gif
from memory. #USE - for dropping beacons/
pixels
location = /beacon {
empty_gif;
}
13. Nginx - Directives
limit_req_zone - Throttle the frequency of
requests for a client. #USE - mitigate DOS
attacks.
http {
limit_req_zone $binary_remote_addr
zone=one:10m rate=1r/s;
...
server {
...
location /search/ {
limit_req zone=one burst=4;
}
14. Nginx - Directives
limit_conn_zone - Throttle concurrency of
connections for a client.
http {
limit_conn_zone $binary_remote_addr
zone=one:2m;
server {
location /download {
limit_conn one 1;
}
}
}
15. Nginx - Directives
stub_status - To get the current status of
nginx. #USE - gives you info like the curr.
active conn., total conn. accepted and
handled, current no. of read/write/wait conn.
location /ngx_stat {
stub_status on;
access_log off;
}
Active connections: 291
server accepts handled requests
16630948 16630948 31070465
Reading: 6 Writing: 179 Waiting: 106
16. Nginx - Directives
map - To map a set of values to a different
set of values. #USE - for dynamically
changing hosts based on URIs.
map $uri $new {
default http://www.domain.com/home/;
/aa http://aa.domain.com/;
/bb http://bb.domain.com/;
/john http://my.domain.com/users/john/;
}
server {
server_name www.domain.com;
rewrite ^$new redirect;
}
17. Nginx - Directives
split_clients - To split clients based on some
conditions. #USE - for A/B testing in
variation in colors/designs.
http {
split_clients "${remote_addr}" $variant {
0.5% .one;
2.0% .two;
- "";
}
server {
location / {
index index${variant}.html;
18. Nginx - Directives
sub_filter - Search and replace content in
the response. #USE - Quick fix for stale
data/ typos?
error_pages - Custom error pages for your
#failwhale moments.
if/set/rewrite - powerful constructs for
condition based execution.
19. Nginx - Builtin Variables
$arg_PARAM - To read the value of a GET
request PARAM.
$http_HEADER - To read the value of any
request HEADER.
20. Nginx - Builtin Variables
$request_time - Measure end to end time.
#caveat - only from read() to write()/
sendfile()
$upstream_response_time - Measure end to
end time of your upstream server (w/
$upstream_addr)
21. Nginx - Modules
Embedded Perl - To execute perl directly
inside nginx.
XSLT - Transform your XML responses to
HTML in nginx.
FLV/MP4 - To stream FLV/MP4 content.
Addition - To add content of other locations
to the current location.
GeoIP/Mail/Image Filter/Memcached modules
