Varnish qconsp 2011
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The document is a comprehensive guide on configuring and using Varnish as a web accelerator (reverse proxy cache) focusing on caching mechanisms, expiration and validation headers, and VCL elements. It covers various Varnish functionalities, including backend configuration, hash methods, and handling HTTP requests, along with auxiliary tools and examples of command usages. Additionally, it explains the grace mode for object persistence and outlines header configuration for different content types.
Varnish qconsp 2011
- 1. Varnish
- 2. Sumário Caching em HTTP
- 4. Caching em HTTP Como funciona um “Acelerador Web” (Reverse Proxy Cache) Expiração (headers Cache-Control, Age e Expires)
- 5. Validação (headers Last-Modified, Etag, If-Modified-Since, If-None-Modified)
- 6. Browser -> Cache -> Backend
- 13. Combinando Expiração e Validação
- 17. Varnish workshop Elementos do vcl
- 18. Fluxo e objetos
- 19. Hash
- 20. Métodos HTTP
- 21. Misc: set/unset, regexp, ttl, headers de diagnóstico
- 22. Persistência: como funciona o grace
- 23. Ferramentas auxiliares: varnishlog, varnishncsa, varnishadm
- 24. Purge/Ban
- 25. Elementos do vcl Os elementos básicos do vcl são: Backend Aqui são especificados os parâmetros de comunicação com o backend e probe (healthcheck) – semelhante à um VIP Subrotinas e módulos Subrotinas não retornam valores
- 26. Além das rotinas pré-definidas (que determinam o fluxo do Varnish) podem ser criadas subrotinas customizadas
- 27. Módulo pode retornar a localização geográfica de um endereço IP ou usar o varnish como um cliente HTTP e buscar cabeçalhos e corpo nos backends Acls Includes Inline C
- 28. backend backend ig { .host = "vip.be.infra"; .probe = { .url = "/healthcheck.html"; .timeout = 34 ms; .interval = 1s; .window = 10; .threshold = 8; } } director baz round-robin { { .backend = ig; } { .backend = com; } }
- 29. acl acl purge { "localhost"; "127.0.0.1"; "10.0.0.0"/8; } acl header { "localhost"; "200.200.100.100"; "10.0.0.0"/8; }
- 30. Include e sub include ”/etc/varnish/functions.inc"; --- sub normalize_user_agent { if(req.http.User-Agent ~ "iPhone|Android") { set req.http.User-Agent = "mobile"; } else { remove req.http.user-agent; } }
- 31. Varnish: Fluxo e Objetos
- 33. Hash sub vcl_hash { if (req.http.user-agent ~ "mobile") { hash_data(req.http.user-agent); } # Vital para virtualhosts hash_data(req.url); hash_data(req.http.host); return (hash); }
- 34. Métodos HTTP if (req.request ~ "(GET|HEAD)") { return(lookup); } # Se for um POST deixa passar sem fazer cache elsif (req.request == "POST") { return(pass); } ...cont
- 35. Métodos HTTP elsif (req.request == "PURGE") { if (!client.ip ~ purge) { error 405 "opt Cache: Purge Not allowed."; } ban_url(req.url); error 200 req.url; } else { error 403 "opt Cache: Request not allowed."; }
- 36. Misc (call, set, regexp) call normalize_accept_encoding; --- sub normalize_accept_encoding { if (req.http.Accept-Encoding) { if (req.http.User-Agent ~ "MSIE 6") { remove req.http.Accept-Encoding; } elsif (req.http.Accept-Encoding ~ "gzip") { set req.http.Accept-Encoding = "gzip"; } elsif (req.http.Accept-Encoding ~ "deflate") { set req.http.Accept-Encoding = "deflate"; } else { remove req.http.Accept-Encoding; } } }
- 37. Misc (ttl, beresp) # se nao for 200, 301, 302 ou 304 = ttl de 5s if (beresp.status != 200 && beresp.status != 301 && beresp.status != 302 && beresp.status != 304) { set beresp.ttl = 5s; } # ttl minimo de 60s para os objetos com retorno 200, 301, 302 e 304 else { if (beresp.ttl < 60s) { set beresp.ttl = 60s; } }
- 38. Persistência Persistência O grace mode permite ao varnish responder lookups mesmo quando um objeto expirou seu ttl enquanto o backend não estiver up ou lento Configuração necessária Em vcl_recv: set req.grace = 3d; Em vcl_fetch: set req.grace = 3d; Importante: É necessário ter o probe na configuração de backend para que o grace funcione.
- 40. varnishlog com suporte a filtros de registros que correspondem múltiplas expressões
- 41. varnishstat
- 42. varnishtop
- 43. varnishncsa com suporte de log com formatos personalizados
- 44. varnishadm # varnishadm -T localhost:6082 "ban req.url ~ /index.html && req.http.host == site.com.br" CLI connected to localhost:6082 # varnishadm -T localhost:6082 "vcl.list" CLI connected to localhost:6082 available 887 boot available 7 1312244228_site.com.br active 382 1312261977_ajuste_site.com.br
- 45. varnishlog $ varnishlog -o -i TxURL,TxHeader 102 TxHeader c Date: Sun, 11 Sep 2011 14:44:26 GMT 102 TxHeader c Last-Modified: Mon, 07 Feb 2011 20:40:38 GMT 102 TxHeader c Cache-Control: max-age=60 102 TxHeader c Expires: Sun, 11 Sep 2011 14:44:31 GMT 102 TxHeader c Vary: Accept-Encoding 102 TxHeader c Connection: keep-alive 102 TxHeader c X-Cache: HIT $ varnishlog -i TxURL,TxHeader -I '(TxURL|Host:)' 47 TxHeader - Host: www.sitea.com.br 47 TxHeader - Host: www.siteb.com.br 47 TxHeader - Host: vhost.sitea.com.br
- 46. varnishstat $ varnishstat 123+18:16:25 Hitrate ratio: 10 44 48 Hitrate avg: 0.9750 0.09705 0.09718 client_conn 45687252 4.27 Client connections accepted client_drop 0 0.00 Connection dropped, no sess/wrk client_req 541868273 50.69 Client requests received cache_hit 522400064 48.87 Cache hits cache_hitpass 0 0.00 Cache hits for pass cache_miss 14239594 1.33 Cache misses backend_conn 2933231 0.27 Backend conn. success backend_unhealthy 753 0.00 Backend conn. not attempted backend_busy 0 0.00 Backend conn. too many backend_fail 0 0.00 Backend conn. failures backend_reuse 12523383 1.17 Backend conn. reuses backend_toolate 2387757 0.22 Backend conn. was closed backend_recycle 14911184 1.40 Backend conn. recycles backend_unused 0 0.00 Backend conn. unused
- 47. varnishtop $ varnishtop -i RxHeader -C -I \^User-Agent -1 1240.00 RxHeader User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/13.0.782.220 Safari/535.1 765.00 RxHeader User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:6.0.2) Gecko/20100101 Firefox/6.0.2
- 48. Configuração dos Headers #Apache Header unset ETag ExpiresActive On ExpiresByType text/css "now plus 10 years" ExpiresByType text/html "now plus 60 seconds" ExpiresByType image/gif "now plus 10 years" ExpiresByType image/png "now plus 10 years" ExpiresByType image/jpeg "now plus 10 years" ExpiresByType application/javascript "now plus 10 years" ExpiresByType application/x-shockwave-flash "now plus 10 years" Header append Cache-Control public env=static-content
- 49. Obrigado! Dúvidas ? iG – Internet Group Flavio Torres [email_address] @flavio_torres