Simply Scalew/ Nginx, Memcached, PHP-FPM and APC

JAMES FULLER 02/13/2013

In this talk...● my experiences working in a high-traffic

environment

● intro to nginx for apache users

● running php with php-fpm

● memcached & caching tips

● identifying bottlenecks / open discussion

The Early Years

Cheap Shared Hosting

Into the fire

A Simple Scaling Architecture

NGINX PHP-FPM

PHP-FPM

PHP-FPM

PHP-FPM

MEMCACHED

MYSQL MASTER

MYSQL SLAVE

ApacheAwesome when you need to assault your server

The classic setup - prefork MPM w/ mod_php● prefork is default mode prior to v2.4

● forks (creates) new process per web resource requested

● runs php via a module (mod_php)

Apache prefork performance killers● Loads all modules for each forked process

● Keepalive timeout

● AllowOverride (.htaccess)

Apache 2.4● Event MPM is now the default MPM in

Apache 2.4

● Event MPM designed to solve the keepalive problem

● Can talk to PHP-FPM via mod_proxy_fcgi

● Needs thread safe php

Many reasons to keep Apache● apache modules

● very mature software

● can tune for good results

● plays nice with nginx!

NGINXRussian for Fast

What is NGINX?● HTTP Server

● Reverse Proxy

● IMAP/POP3 proxy server

● Open Source

Who is using nginx?

Nginx performance advantages● event based connection handling

● low/predictable memory consumption

● works well in low resource environments (VPS)

● can handle tens of thousands of concurrent requests*

Nginx as a frontend

● serve static files

● frontend for apache for php

● no apache, via PHP-FPM

● serve content directly from memcached

Nginx Configurationuser nginx;

worker_processes 1;

error_log /var/log/nginx/error.log warn;

pid /var/run/nginx.pid;

events {

worker_connections 1024;

}

http {

server {

location / {

#do something

}

}

}

a series of blockshttp {

access_log /var/log/nginx/access.log main;

include /etc/nginx/conf.d/*.conf;

gzip on;

server {

server_name myserver.com www.myserver.com

listen 80;

location / {

}

}

}

server blocksserver {

listen 80 default_server;

server_name star.yourdomain.com *.yourdomain.com;

root /PATH/TO/WEBROOT;

error_page 404 errors/404.html;

access_log logs/star.yourdomain.com.access.log;

index index.php index.html index.htm;

}

location blocks# static file 404's not logged + expires header set to maxage

location ~* \.(jpg|jpeg|gif|css|png|js|ico|html)$ {

access_log off;

expires max;

}

# deny htaccess

location ~ /\.ht {

deny all;

}

PHP-FPMit's like mod_php without Apache

PHP-FPM are you listening?● included with php as of 5.3.3

● runs as a daemon○ listens for requests via socket or port

(FastCGI)

● Decouple web server from executing php code

Talking to php-fpm# pass the PHP scripts to FastCGI server

# listening on 127.0.0.1:9000

location ~ \.php$ {

root html;

fastcgi_pass 127.0.0.1:9000;

#fastcgi_pass unix:/tmp/php.socket

fastcgi_index index.php;

fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;

include fastcgi_params;

}

Nginx for load balancing● round robin

● least connections

● ip segmenting

● sticky backends

upstream serverupstream backend {

server backend1.example.com weight=5;

server backend2.example.com:8080;

server unix:/tmp/backend3;

}

server {

location / {

proxy_pass http://backend;

}

}

apache frontendupstream backend {

server 192.168.1.2;

server 192.168.1.3;

server 192.168.1.4;

#etc

}

location ~ \.php$ {

proxy_pass http://backend; proxy_set_header X-Real-IP $remote_addr;

}

Nginx ModulesCore

Access

Auth Basic

Auto Index

Browser

Charset

Empty GIF

FastCGI

Geo

Gzip

Headers

Index

Limit Requests

Limit Zone

Limit Conn

Log

Map

Memcached

Proxy

Referer

Rewrite

SCGI

Split Clients

SSI

Upstream

User ID

uWSGI

X-Accel

Addition

Degradation

Embedded Perl

FLV

GeoIP

Google Perftools

Gzip Precompression

Image Filter

MP4

Random Index

Real IP

Secure Link

SSL

Stub Status

Substitution

WebDAV

XSLT

OPTIONAL

Caching in PHPCache is king

What is Memcached?

● invented by Brad Fitzpatrick to solve livejournal performance problems

● distributed key value store

● super fast

Set up Memcached instances

● small sites can use as little as 25MB

● best results and reliability in a cluster

Talking to Memcached with PHP● naming disaster

● php has two memcached extensions○ memcache○ memcached - better support for advanced

features○ wtf?

● memcache(d) php extension only on nix platforms (no windows)

Connecting to Memcached<?php

$cache = new Memcache;

$cache ->addServer('192.168.1.2', 11211, ..[OPTIONS]..);

$cache ->addServer('192.168.1.3', 11211, ..[OPTIONS]..);

$cache ->addServer('192.168.1.4', 11211, ..[OPTIONS]..);

$cache ->addServer('192.168.1.5', 11211, ..[OPTIONS]..);

Simple Cache strategy<?php$key = 'mystash';$data = $cache->get($key);

if ($data === false) {

$data = 'fill up the data'; $cache->set($key, $data, ..[OPTIONS]..);}

Be smart about caching

● cache expensive things (network, db)

● stale content can be much worse than slow content

● have a plan to expire cache entries

APC● Opcode cache

● Stores ready-to-run machine code

● will eventually be replaced by zend optimizer (php 5.5)

● has data caching api

Bottlenecks & Benchmarking

Try to identify bottlenecks

Find out what is slow● web server

● database

● bandwidth / infrastructure

● php code

Avoid the file system● does not scale well

● expensive to make fast

● cloud hosting and multi-server implementations more complicated

Database

● often the culprit

● choose the right technologies

● don't skimp on hardware

Other people's benchmarks● Monitoring and testing is key

● avoid magical thinking:○ "Magical thinking is thinking that one's thoughts by themselves can

bring about effects in the world or that thinking something corresponds with doing it"

● use tools like newrelic with actual users

It's all about the end user

● avoid blocking javascript

● be aware of static assets

● use expires headers correctly

Seriously, try New Relic● FREE basic account, with PRO TRIAL

● runs as a deamon + php extension

● allows deep inspection of web transactions

● need ability to install package on server

Homework

Dig one level deeper● We work in abstractions

● Understand the systems that deliver your code to the browser

● Identify the problems before implementing the solutions

Resources● nginx wiki - http://wiki.nginx.org/● php-fpm - http://php.net/manual/en/install.fpm.php● memcached - http://memcached.org/● memcache extensions

○ memcache - http://php.net/manual/en/book.memcache.php

○ memcache(d) - http://php.net/manual/en/book.memcached.php

● apc - http://php.net/manual/en/book.apc.php● newrelic - http://newrelic.com/

Questions?

James Fuller

@j_blotus

http://www.jblotus.com