CDN and Cloud - PHPFest 2011

CDN & Cloud Junho Choi <[email protected]> CDNetworks h7p://www.cdnetworks.com rev. 3

Who am I?

  Junho Choi (최준호)   CTO/APAC, VP of Engineering | CDNetworks hAp://www.cdnetworks.com   FreeBSD CommiAer(ports) ([email protected], 2001-‐2010)   Korea FreeBSD Users Group hAp://www.kr.freebsd.org since 1999   TwiAer: junhochoi

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Contents

  CDN – what problem to solve   Technology in CDN   How to uZlize CDN/Cache using PHP   Cloud CompuZng & CDN

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A typical web site

  You built a fancy web site!   As your website is ge_ng popular, you are ge_ng more and more traffic.   Your website will be slow when more users visit.   Your website will be slow when users from other countries visit.   Your website can be down due to hardware failure, network failure.   Your website will be down when there is a spike of traffic because your we

bsite is suddenly popular on famous news site, twiAer, slashdot, facebook etc.

  Your website is not scalable when you want to expand more   You want to have a streaming video on your website but don’t want to bu

y a license for commercial streaming soluZon such as Flash Media or Windows Media.

  …

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Content Delivery Network

  Problem to solve •  Network Distance •  Reliability •  Scalability

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Problem to Solve – Network Distance

EMEA HQ

End-user

First Mile Same Data Center

Same ISP Low latency

High Bandwidth

Middle Mile Bad Routing

Network Failure Long distance

Last Mile Same LocaZon

Same ISP Low latency

Low Bandwidth

  Middle Mile Problem

“Origin Server” Customer’s web site

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Problem to Solve – Network Distance

EMEA HQ

End-user

First Mile Middle Mile Last Mile

Place edge (caching or mirroring) server on nearest locaZon to end user

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“Origin Server” Customer’s web site

“Edge Server” CDN Cache

Problem to Solve – Reliability

EMEA HQ

End-user


SZll able to access on CDN Edge server

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Problem to Solve – Scalability

EMEA HQ

End-user


Put more edge servers instead of customer Content is cached; no increase on origin server traffic

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History

  Late 90’s, SandPiper was first CDN company and Akamai made it a successful market around 1999~2000

  In Korea, CDN service started around 2000 by a few startups including CDNetworks

  Now CDN provider and ISP are compeZng each other

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CDN Services

  HTTP/HTTPS Delivery •  Web Caching Model •  Mirroring Model

  Streaming •  Windows Media Streaming (VOD, Live) •  Flash Media Streaming (VOD, Live) •  Caching and mirroring model

  AddiZonal Service •  Storage as a origin •  P2P delivery (aka grid delivery)

  Pay for usage: traffic (Gbytes) or bandwidth (Gbit/sec)

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In real world

  Websites (HTTP/HTTPS) •  E-‐Commerce

−  A large number of images −  Accessing from many users

•  Social commerce −  A few number of images −  Many users at the same Zme – high spike

•  Web site with global audience   Streaming

•  E-‐learning Contents for students •  Live event for a big sports game •  User Generated Contents

  Online Gaming •  Launching a new game •  Release update or patch

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Traffic PaNern of a web site

Website only can handle this (limited by bandwidth, server, etc)

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As your website ge_ng popular, there will be unexpected traffic paAerns

High Level Architecture

GSLB

Management

Log Processing

Operator Portal

Cache

Storage Streaming

Monitoring

Router

Cache

Storage Cache

Monitoring

Router

Cache

Storage Cache

Monitoring

Router

Customer Portal

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Data Center, or PoP (Point Of Presence)

Admin PoP or Control Center

Main Technology

  GSLB •  Global Server Load Balancing •  Typically DNS server which do load balancing between mulZple servers and ne

tworks •  Most CDN provider use GSLB

  Cache •  Web Cache for HTTP/HTTPS •  Cache objects in storage •  When end user access the contents, it will serve objects from cache if possible •  Controlled by several configuraZon parameter and HTTP response from origin

  Portal •  Large data processing – processing daily logs •  Controllable via UI for operators

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CDN in website

hAp://www.kr.cdnetworks.com/index.php

hAp://www.kr.cdnetworks.com/images/common/main_logo.gif

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Typical web site has a lot of objects Inside – images, flash, video, js, css etc

DNS lookup example

% dig www.kr.cdnetworks.com ;; QUESTION SECTION: ;www.kr.cdnetworks.com. IN A ;; ANSWER SECTION: www.kr.cdnetworks.com. 3420 IN CNAME www.kr.cdnetworks.com.cdngc.net. www.kr.cdnetworks.com.cdngc.net. 20 IN A 61.110.226.28 www.kr.cdnetworks.com.cdngc.net. 20 IN A 61.110.226.15 ;; AUTHORITY SECTION: cdngc.net. 68200 IN NS ns2.panthercdn.com. cdngc.net. 68200 IN NS ns1.panthercdn.com. ;; ADDITIONAL SECTION: ns1.panthercdn.com. 64021 IN A 205.252.255.11 ns2.panthercdn.com. 48212 IN A 67.72.21.11

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DNS lookup example

Root DNS (.com, .net)

DNS for cdnetworks.com

“What’s IP address of www.kr.cdnetworks.com?”

Resolver Local DNS End User

Browser

“What’s DNS Server IP address of cdnetworks.com?”

“www.kr.cdnetworks.com is (CNAME) www.kr.cdnetworks.cdngc.net”

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DNS lookup example

Root DNS (.com, .net)

DNS for cdnetworks.com

“What’s IP address of www.kr.cdnetworks.com?”

Resolver Local DNS End User

Browser

“What’s DNS Server IP address of cdnetworks.com?” “What’s DNS Server IP address of cdngc.net?”

DNS for cdngc.net (GSLB) “What’s IP address of www.kr.cdnetworks.com.cdngc.net?” “61.110.226.28 and 61.110.226.15” (IP of Cache Servers)

“www.kr.cdnetworks.com is www.kr.cdnetworks.cdngc.net”

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Object delivery and whole site delivery

  Object delivery •  Only serves specified file (image, video, js, css) and sZll other page is served fr

om origin site


hAp://images.kr.cdnetworks.com/images/common/main_logo.gif

www.kr.cdnetworks.com != images.kr.cdnetworks.com

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Object delivery and whole site delivery

  Whole Site Delivery •  CDN covers whole site – including objects, dynamic pages etc. •  Need more aAenZon – what is cacheable and not cacheable not to break sites


hAp://www.kr.cdnetworks.com/images/common/main_logo.gif

www.kr.cdnetworks.com == www.kr.cdnetworks.com

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Cacheable and non-‐cacheable

  Objects are cacheable •  In Edge Cache Server •  In Proxy Cache in ISP or your network •  In Browser Cache •  TTL (Time To Live) – lifeZme in Edge Cache

•  Images, Videos, Documents, CSS, Javascript •  Not changed by \me, loca\on, session, cookie, browser

  Objects are non-‐cacheable •  Dynamic response from PHP/JSP/ASP/… •  Cannot be stored in Edge Cache/Proxy/Browser Cache

•  Dynamically generated HTML pages, AJAX response, API •  Same URL but different contents by \me, loca\on, session, cookie, browser

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Cache Control

  You can control cache-‐ability of objects using various headers in HTTP response. •  CDN Edge Cache •  Browser Cache (local PC)

  2 Basic Status •  Cache Hit: when cache already has the object •  Cache Miss: cache will pull the object from origin and store

  Cache related headers •  Last-‐Modified, Etag •  Cache-‐Control •  Pragma •  Vary •  Expires

  Cache/Proxy related headers •  Via, Age

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Example of non-‐cacheable object

% curl -‐I http://www.naver.com HTTP/1.1 200 OK Date: Thu, 26 May 2011 12:23:01 GMT Server: Apache Cache-‐Control: no-‐cache, no-‐store, must-‐revalidate Pragma: no-‐cache P3P: CP="CAO DSP CURa ADMa TAIa PSAa OUR LAW STP PHY ONL UNI PUR FIN COM NAV INT DEM STA PRE" Cache-‐Control: no-‐cache, no-‐store, must-‐revalidate Pragma: no-‐cache Vary: Accept-‐Encoding,User-‐Agent Connection: close Content-‐Type: text/html; charset=UTF-‐8

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Example of non-‐cacheable object – from iPod?

% curl -‐I -‐A "Mozilla/5.0 (iPod; U; CPU iPhone OS 4_3_1 like Mac OS X; en-‐us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8G4 Safari/6533.18.5" http://www.naver.com HTTP/1.1 302 Found Date: Thu, 26 May 2011 12:37:32 GMT Server: Apache Location: http://m.naver.com Vary: Accept-‐Encoding Connection: close Content-‐Type: text/html; charset=iso-‐8859-‐1

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How to make non-‐cacheable object in PHP

  Using header() funcZon <?php header(“Cache-‐Control: no-‐cache, no-‐store, must-‐revalidate”); header(“Pragma: no-‐cache”); header(“Vary: Accept-‐Encoding, User-‐Agent”); ?> Hello World

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How to make non-‐cacheable object in PHP

% curl -‐D-‐ http://www.kr.freebsd.org/~cjh/phpfest2011/nc.php HTTP/1.1 200 OK Date: Thu, 26 May 2011 13:09:11 GMT Server: Apache/1.3.41 (Unix) mod_perl/1.31 DAV/1.0.3 PHP/4.4.9 with Suhosin-‐Patch mod_ssl/2.8.31 OpenSSL/0.9.7e-‐p1 MS-‐Author-‐Via: DAV X-‐Powered-‐By: PHP/4.4.9 Cache-‐Control: no-‐cache, no-‐store, must-‐revalidate Pragma: no-‐cache Vary: Accept-‐Encoding, User-‐Agent Transfer-‐Encoding: chunked Content-‐Type: text/html; charset=euc-‐kr Hello World

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How to make non-‐cacheable object in PHP (2)

<?php header(“Cache-‐Control: no-‐cache, no-‐store, must-‐revalidate”); header(“Pragma: no-‐cache”); header(“Vary: Accept-‐Encoding, User-‐Agent”); if (strstr($_SERVER["HTTP_USER_AGENT"], "iPhone OS")) { print "<h1>Hello iOS</h1>"; print "<h1>Hello iOS</h1>"; print "<h1>Hello iOS</h1>"; exit; } ?> Hello World

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Example of cacheable object

% curl -‐I 'http://static.naver.com/www/u/2010/0611/nmms_215646753.gif' HTTP/1.1 200 OK Date: Thu, 26 May 2011 12:27:30 GMT Server: Apache/2.0.52 Last-‐Modified: Fri, 11 Jun 2010 12:56:46 GMT ETag: "a06-‐abe73f80" Accept-‐Ranges: bytes Content-‐Length: 2566 Cache-‐Control: max-‐age=604800 Content-‐Type: image/gif Via: 1.1 SI2286-‐239 (Jaguar/3.0-‐62) Age: 3 Expires: Thu, 02 Jun 2011 12:27:23 GMT

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TTL is 7 day

Example of cacheable object in CDN Server

% curl -‐I 'http://static.naver.com/www/u/2010/0611/nmms_215646753.gif' HTTP/1.1 200 OK Date: Thu, 26 May 2011 12:27:30 GMT Server: Apache/2.0.52 Last-‐Modified: Fri, 11 Jun 2010 12:56:46 GMT ETag: "a06-‐abe73f80" Accept-‐Ranges: bytes Content-‐Length: 2566 Cache-‐Control: max-‐age=604800 Content-‐Type: image/gif Age: 3 Expires: Thu, 02 Jun 2011 12:27:23 GMT

% curl -‐I 'http://static.naver.com/www/u/2010/0611/nmms_215646753.gif' HTTP/1.1 200 OK Date: Thu, 26 May 2011 12:31:23 GMT Server: Apache/2.0.52 Last-‐Modified: Fri, 11 Jun 2010 12:56:46 GMT ETag: "a06-‐abe73f80" Accept-‐Ranges: bytes Content-‐Length: 2566 Cache-‐Control: max-‐age=604800 Content-‐Type: image/gif Age: 53 Expires: Thu, 02 Jun 2011 12:30:30 GMT

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Age: header value is residing Zme (second) in Edge Cache. In this case this object will stored in Edge Cache for 7 day (604800 sec).

How to make cacheable object in PHP

<?php header("Cache-‐Control: max-‐age=604800"); // tell CDN cache to store object for next 24 hours header("Content-‐Type: text/plain"); header("Content-‐Length: ".filesize("test.txt")); readfile("test.txt"); ?> % curl -‐D-‐ http://www.kr.freebsd.org/~cjh/phpfest2011/c.php HTTP/1.1 200 OK Date: Thu, 26 May 2011 13:35:32 GMT Server: Apache/1.3.41 (Unix) mod_perl/1.31 DAV/1.0.3 PHP/4.4.9 with Suhosin-‐Patch mod_ssl/2.8.31 OpenSSL/0.9.7e-‐p1 MS-‐Author-‐Via: DAV X-‐Powered-‐By: PHP/4.4.9 Cache-‐Control: max-‐age=604800 Content-‐Length: 17 Content-‐Type: text/plain;charset=euc-‐kr THIS IS TEST.TXT

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How to make cacheable object in PHP (2)

HTTP/1.1 200 OK Date: Thu, 26 May 2011 15:28:06 GMT Server: PWS/1.7.2.3 Cache-‐Control: max-‐age=604800 Expires: Thu, 02 Jun 2011 15:28:07 GMT Age: 0 Content-‐Length: 17 Content-‐Type: text/plain;charset=euc-‐kr Connection: keep-‐alive THIS IS TEST.TXT

HTTP/1.1 200 OK Date: Thu, 26 May 2011 15:28:15 GMT Server: PWS/1.7.2.3 Cache-‐Control: max-‐age=604800 Expires: Thu, 02 Jun 2011 15:28:06 GMT Age: 9 Content-‐Length: 17 Content-‐Type: text/plain;charset=euc-‐kr Connection: keep-‐alive THIS IS TEST.TXT

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As you can see now this URL is cached in Edge Cache, although this page is generated by PHP. Also check origin server if access from cache exists should be none

CDN & Cloud

  Cloud CompuZng provide very similar purpose of CDN such as reliability and scalability, but not helpful to solve other problems such as Network Distance (middle mile) problem •  Cloud: Most servers are located in ONE locaZon

  Combining CDN with Cloud service •  Cloud CompuZng can solve a lot of origin issue such as scalability •  CDN can provide fast access to cacheable objects •  For high performance, global-‐accessed websites •  Example

−  Origin Server use VM Cloud and Storage −  Use CDN for caching and low latency

  Cloud Service company has compeZng products with CDN •  Amazon’s S3 storage + CloudFront

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Example: CloudSleuth.net

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Example: CloudSleuth.net

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Other keywords

  ApplicaZon Delivery   WAN AcceleraZon/OpZmizaZon   Edge CompuZng   Web Page OpZmizaZon   Mobile OpZmizaZon   …

Thank you!

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