Scaling WordPress - WordCamp Antwerp 2016

Slides for my WordPress scalability talk at WordCamp Antwerp 2016. http://2016.antwerp.wordcamp.org

Transcript

1. By Thijs Feryn
2. 3 statements
3. Slow websites suck
4. Web performance is an essential part of the user experience
5. Down Slowdown ~ downtime
6. Performance != Scalability
7. Performance: speed
8. Scalability: constant speed with increasing load
9. Improve
10. Hi, I’m Thijs
11. I’m @ThijsFeryn on Twitter
12. I’m an Evangelist At
13. I’m a at board member
14. What’s the problem?
15. Infrastructure
16. Code
17. The context
18. ✓Tremendously popular ✓Even the big boys use it ✓Not the best code ✓It does the job ✓Powered by the LAMP stack The context: Wordpress
19. Identify slowest parts
20. Optimize database
21. ✓More RAM ✓Faster disks ✓More database servers ✓Master-slave replication ✓Read/write splitting (HyperDB) ✓Query/Object caching (Redis) Optimize database
22. Optimize runtime
23. ✓More RAM ✓Faster disks ✓More/faster CPUs ✓More servers ✓OPCache ✓PHP-FPM ✓Recent PHP version ✓HHVM or PHP 7? ✓Nginx or Apache? Optimize runtime
24. Optimize code
25. After a while you hit the limits
26. Optimize database Optimize runtime A void A void
27. Don’t recompute if the data hasn’t changed
28. Cache
29. 3 x 2 = ?
30. ✓WP Supercache ✓W3 Total Cache ✓Wordfence Cache ✓WP Rocket Wordpress caching?
31. ✓WP Supercache ✓W3 Total Cache ✓Wordfence Cache ✓WP Rocket Wordpress caching? Forget about those* *sometimes
32. Varnish
33. Normally User Server
34. With Varnish User Varnish Server
36. Stores HTTP output in memory
37. Respects cache-control headers
38. For page caching
39. Could be thousands of times faster
40. There are rules
41. ✓Only GET & HEAD ✓No authorization headers ✓No cookies ✓No set-cookies ✓Valid cache-control/expires headers When does Varnish cache? Some rules …
42. PROBLEM !!!
43. Dealing with state
44. Varnish Configuration Language
45. ✓ Remove all cookies & set-cookies from static assets ✓ Remove all tracking cookies ✓ Don't cache if wordpress_ or comment_ cookies are present ✓ Or just remove all non-Wordpress cookies ✓ Don't cache wp-login or wp-admin pages ✓ Don't cache preview pages ✓ Normalize URL ✓ Anonimize HTTP output ✓ Provide PURGE logic Required VCL changes
46. vcl 4.0; import std; backend default { .host = "127.0.0.1"; .port = "8080"; .max_connections = 300; .first_byte_timeout = 100s; .connect_timeout = 10s; .between_bytes_timeout = 5s; } acl purge { "192.168.33.10"; "localhost"; "127.0.0.1"; "::1"; } sub purge_regex { ban("obj.http.X-Req-URL ~ " + req.url + " && obj.http.X-Req-Host == " + req.http.host); } sub purge_exact { ban("obj.http.X-Req-URL == " + req.url + " && obj.http.X-Req-Host == " + req.http.host); } sub purge_page { set req.url = regsub(req.url, "\?.*$", ""); ban("obj.http.X-Req-URL-Base == " + req.url + " && obj.http.X-Req-Host == " + req.http.host); }
47. Make Varnish aware of Wordpress
48. https://gist.github.com/ ThijsFeryn/ aabd6d7ed425fb6614279e836d 9848c5 Download VCL here
49. Control Time To Live
50. sub vcl_backend_response { set beresp.ttl = 3h; } Control Time To Live
51. <ifModule mod_headers.c> Header set Cache-Control "public, max-age=3600" <filesMatch "\.(7z|avi|bmp|bz2|css|csv|doc|docx|eot|flac|flv| gif|gz|ico|jpeg|jpg|js|less|mka|mkv|mov|mp3|mp4|mpeg|mpg|odt|otf| ogg|ogm|opus|pdf|png|ppt|pptx|rar|rtf|svg|svgz|swf|tar|tbz|tgz| ttf|txt|txz|wav|webm|webp|woff|woff2|xls|xlsx|xml|xz|zip)$"> Header set Cache-Control "public, s-maxage=2592000" </filesMatch> </ifModule> Control Time To Live Apache .htaccess
52. add_header Cache-Control “public, s-maxage=3600;” Control Time To Live Nginx vhost config
53. Purging
54. https://wordpress.org/ plugins/varnish-http-purge/ Plugin that hooks into the CMS Invalidates cache
55. Performing the purge curl -XPURGE "http://example.com/bla" Wordpress does this internally Uses VCL logic at the Varnish end
56. URLs to purge / /category/uncategorised/ /author/admin/ /hello-world/ /feed/atom/ /feed/rdf/ /feed/rss/ /feed /comments/feed/ /hello-world/feed/ Example
57. Debugging
58. sub vcl_deliver { if (obj.hits > 0) { set resp.http.X-Cache = "HIT"; } else { set resp.http.X-Cache = "MISS"; } } Debugging
59. Varnishlog Varnishtop Varnishncsa Monitor Varnish behaviour
60. What about SSL/TLS?
61. Varnish does not support SSL/TLS
62. You have to terminate SSL/TLS yourself
63. Varnish 4.1 supports PROXY protocol
64. ✓HAProxy ✓Hitch ✓Stud ✓Nginx SSL offloader
65. Offload SSL User Varnish Server SSL offloader
66. User SSL offloading & load balancing Varnishes Servers Load balancer + SSL offloader HAProxy loadbalancers
67. Make Wordpress protocol aware define('FORCE_SSL_ADMIN', true); if ($_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https'){ $_SERVER['HTTPS']='on'; } Header set by SSL offloader
68. What about
69. ✓Object caching ✓Session storage ✓Stanalone ✓Replicated ✓Clustered Redis
70. Consistent state When loadbalancer switches to another server
71. Cheers, hope this helps!
72. Don’t recompute if the data hasn’t changed
73. Varnish