Varnish, the high-performance HTTP accelerator. Is it really a high performance valhalla?

1. Varnish, the high performance valhalla?
Kings of Code 2011

2. JEROEN VAN DIJK
∂ CTO @ Enrise
∂ Email : jeroen@enrise.com
∂ Twitter: @neorey
∂ Open source addict
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3. JEROEN VAN DIJK
∂ CTO @ Enrise
∂ Email : jeroen@enrise.com
∂ Twitter: @neorey
∂ Open source addict
2

4. THE ENRISE RESTAURANT
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5. THE ENRISE RESTAURANT
∂ We want to prepare the best dishes
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6. THE ENRISE RESTAURANT
∂ We want to prepare the best dishes
∂ With the best ingredients
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7. THE ENRISE RESTAURANT
∂ We want to prepare the best dishes
∂ With the best ingredients
∂ To create a magical client experience!
∂ Engineers are our top chefs!
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8. BEFORE WE START
WHO KNOWS
RFC 2616?
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9. BEFORE WE START
WHO KNOWS
HTTP?
5

10. BEFORE WE START
WHO THINKS
HE/SHE KNOWS
HTTP?
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11. STANDARD PROXY
∂ Wikipedia : Proxy
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12. REVERSE PROXY
∂ Wikipedia : Reverse proxy
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13. REVERSE PROXY
∂ Wikipedia : Reverse proxy
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14. REVERSE PROXIES
∂ Wikipedia : Reverse proxy
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15. REVERSE PROXIES
∂ Wikipedia : Reverse proxy
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16. REVERSE PROXIES
∂ Wikipedia : Reverse proxy
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17. WHAT IS VARNISH? (1)
∂ NOT a webserver!
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18. WHAT IS VARNISH? (1)
∂ Caching reverse proxy
∂ NOT a webserver!
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19. WHAT IS VARNISH? (1)
∂ Caching reverse proxy
∂ Load balancer
∂ NOT a webserver!
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20. WHAT IS VARNISH? (1)
∂ Caching reverse proxy
∂ Load balancer
∂ Fail over system
∂ NOT a webserver!
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21. WHAT IS VARNISH? (1)
∂ Caching reverse proxy
∂ Load balancer
∂ Fail over system
∂ HTTP Accelerator
∂ NOT a webserver!
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22. WHAT IS VARNISH? (2)
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23. WHAT IS VARNISH? (2)
∂ Originally built for a Norwegian newspaper
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24. WHAT IS VARNISH? (2)
∂ Originally built for a Norwegian newspaper
∂ > 545k new hostnames in December 2010
§ NetCraft monthly survey
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25. WHAT IS VARNISH? (2)
∂ Originally built for a Norwegian newspaper
∂ > 545k new hostnames in December 2010
§ NetCraft monthly survey
∂ Known users
§ Wikileaks
§ Facebook
§ Twitter
§ SlashDot
∂ Massive growth in usage
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26. WHAT IS VARNISH? (3)
∂ Scaling limitations currently unknown
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27. WHAT IS VARNISH? (3)
∂ Designed for 64bit architecture
∂ Scaling limitations currently unknown
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28. WHAT IS VARNISH? (3)
∂ Designed for 64bit architecture
∂ Highly scalable
∂ Scaling limitations currently unknown
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29. WHAT IS VARNISH? (3)
∂ Designed for 64bit architecture
∂ Highly scalable
§Varnish in front of Varnish(es)
∂ Scaling limitations currently unknown
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30. WHAT IS VARNISH? (3)
∂ Designed for 64bit architecture
∂ Highly scalable
§Varnish in front of Varnish(es)
∂ Perfect browser cache solution
∂ Scaling limitations currently unknown
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31. WHAT IS VARNISH? (3)
∂ Designed for 64bit architecture
∂ Highly scalable
§Varnish in front of Varnish(es)
∂ Perfect browser cache solution
§Prevent those hard refresh calls!
∂ Scaling limitations currently unknown
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32. INTERNALS (1)
∂ Possible request paths
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33. INTERNALS (2)
∂ Optimal request path
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34. INTERNALS (3)
∂ Caching request path
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35. INTERNALS (4)
∂ Prevent caching
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36. INTERNALS (5)
∂ Bypassing Varnish
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37. INTERNALS (6)
∂ Errors or issueing restarts
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38. VARNISH CONFIGURATION LANGUAGE (1)
∂ Compiled to C when run
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39. VARNISH CONFIGURATION LANGUAGE (1)
∂ 11 subroutines (vcl_recv, vcl_hash, etc ...)
∂ Compiled to C when run
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40. VARNISH CONFIGURATION LANGUAGE (1)
∂ 11 subroutines (vcl_recv, vcl_hash, etc ...)
∂ Backend(s)
∂ Compiled to C when run
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41. VARNISH CONFIGURATION LANGUAGE (1)
∂ 11 subroutines (vcl_recv, vcl_hash, etc ...)
∂ Backend(s)
∂ Directors (random, round robin, hash)
∂ Compiled to C when run
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42. VARNISH CONFIGURATION LANGUAGE (1)
∂ 11 subroutines (vcl_recv, vcl_hash, etc ...)
∂ Backend(s)
∂ Directors (random, round robin, hash)
∂ Access control lists
∂ Compiled to C when run
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43. VARNISH CONFIGURATION LANGUAGE (1)
∂ 11 subroutines (vcl_recv, vcl_hash, etc ...)
∂ Backend(s)
∂ Directors (random, round robin, hash)
∂ Access control lists
∂ Saint and grace mode
∂ Compiled to C when run
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44. VARNISH CONFIGURATION LANGUAGE (1)
∂ 11 subroutines (vcl_recv, vcl_hash, etc ...)
∂ Backend(s)
∂ Directors (random, round robin, hash)
∂ Access control lists
∂ Saint and grace mode
∂ Custom subroutines
∂ Compiled to C when run
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45. VARNISH CONFIGURATION LANGUAGE (1)
∂ 11 subroutines (vcl_recv, vcl_hash, etc ...)
∂ Backend(s)
∂ Directors (random, round robin, hash)
∂ Access control lists
∂ Saint and grace mode
∂ Custom subroutines
∂ Inline C
∂ Compiled to C when run
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46. VARNISH CONFIGURATION LANGUAGE (1)
∂ 11 subroutines (vcl_recv, vcl_hash, etc ...)
∂ Backend(s)
∂ Directors (random, round robin, hash)
∂ Access control lists
∂ Saint and grace mode
∂ Custom subroutines
∂ Inline C
∂ Since v3.0 : VMODS
∂ Compiled to C when run
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47. VARNISH CONFIGURATION LANGUAGE (2)
if (req.request == “GET” &&
req.url ~ “.(gif|jpg|jpeg|bmp|png|ico)$”) {
unset req.http.cookie;
set req.grace = 1m;
return(lookup);
}
∂ Cache images in vcl_recv
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48. VARNISH CONFIGURATION LANGUAGE (3)
if (req.http.cookie) {
set req.http.Cookie = regsuball(req.http.Cookie,
"__utm.=[^;]+(; )?", "");
if (req.http.cookie ~ "^ *$") {
remove req.http.cookie;
}
}
∂ Remove Google Analytics in vcl_recv
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49. VARNISH CONFIGURATION LANGUAGE (4)
backend default {
.host="192.168.1.10";
.port="8080";
.probe={
.url=”/test.php”;
}
}
backend second {
.host="192.168.1.20";
.port="8080";
}
∂ Multiple backend configuration
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50. VARNISH CONFIGURATION LANGUAGE (5)
director balance random {
{ .backend = default; .weight = 1; }
{ .backend = second; .weight = 2; }
}
sub vcl_recv {
set.req.backend = balance;
return(pass);
}
∂ Load balanced 33 / 66 % config
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51. VARNISH CONFIGURATION LANGUAGE (6)
if (obj.hits > 0) {
#if hit add hit count
set resp.http.X-Cache = "HIT-" obj.hits;
} else {
set resp.http.X-Cache = "MISS”;
}
∂ Adding headers on response
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52. VARNISHING WORDPRESS (1)
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53. VARNISHING WORDPRESS (1)
∂ Siege on standard WordPress homepage
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54. VARNISHING WORDPRESS (1)
∂ Siege on standard WordPress homepage
§No Varnish
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55. VARNISHING WORDPRESS (1)
∂ Siege on standard WordPress homepage
§No Varnish
§Default Varnish installation
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56. VARNISHING WORDPRESS (1)
∂ Siege on standard WordPress homepage
§No Varnish
§Default Varnish installation
§Custom VCL configuration
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57. VARNISHING WORDPRESS (2)
∂ No Varnish
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58. VARNISHING WORDPRESS (2)
∂ No Varnish
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59. VARNISHING WORDPRESS (2)
∂ No Varnish
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60. VARNISHING WORDPRESS (3)
∂ Default Varnish
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61. VARNISHING WORDPRESS (3)
∂ Default Varnish
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62. VARNISHING WORDPRESS (3)
∂ Default Varnish
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63. VARNISHING WORDPRESS (4)
# Drop any cookies sent to WordPress.
sub vcl_recv {
unset req.http.cookie;
}
# Drop any cookies WordPress tries to send back
sub vcl_fetch {
unset beresp.http.set-cookie;
}
∂ Kill those cookies!!
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64. VARNISHING WORDPRESS (5)
∂ Custom Varnish
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65. VARNISHING WORDPRESS (5)
∂ Custom Varnish
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66. VARNISHING WORDPRESS (5)
∂ Custom Varnish
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67. OTHER PITFALLS
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68. OTHER PITFALLS
∂ Accept headers
§application/vnd.kingsofcode.speakers+xml;
§return “Vary: Accept” header
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69. OTHER PITFALLS
∂ Accept headers
§application/vnd.kingsofcode.speakers+xml;
§return “Vary: Accept” header
∂ Accept-encoding header
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70. OTHER PITFALLS
∂ Accept headers
§application/vnd.kingsofcode.speakers+xml;
§return “Vary: Accept” header
∂ Accept-encoding header
∂ Vary: User-Agent header
∂ Not specifically Varnish issues
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71. EDGE SIDE INCLUDES (1)
∂ Markup language
∂ Co-authored Akamai, IBM, Oracle & more
∂ Extensive features
∂ Very powerful for content assembly
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72. EDGE SIDE INCLUDES (2)
∂ if ... else
§ <esi:choose><esi:when> ... <esi:otherwise>
∂ Variables
§ <esi:assign> and <esi:vars>
∂ Varnish implements only one feature!
§ <esi:include src=”uri” />
∂ Examples? http://esi-examples.akamai.com
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73. EDGE SIDE INCLUDES (3)
if (req.url ~ "^/url/to/esi/snippets") {
unset beresp.http.set-cookie;
}
## enable esi on header from backend
if (beresp.http.enable-esi == "1") {
set beresp.do_esi = true; //varnish 3.0
unset beresp.http.enable-esi;
}
∂ VCL config for ESI
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74. EDGE SIDE INCLUDES (4)
∂ Where are the ESI’s?
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75. EDGE SIDE INCLUDES (5)
∂ Different TTL’s for content snippets
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76. TOOLS
∂Varnishstat
∂Varnishsizes
∂Varnishtop
∂Varnishadm
∂Varnishlog
∂ You can’t go without
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77. VARNISHLOG
∂ Log hits
§ varnishlog -o VCL_Call hit | grep RxURL
∂ Log misses
§ varnishlog -i TxURL
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78. VARNISHLOG
∂ Request of a gif image by client
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79. VARNISHLOG
∂ Request of a gif image by client
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80. VARNISHLOG
∂ Request of a gif image by client
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81. VARNISHLOG
∂ Request of a gif image by client
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82. CAVEATS
∂ Unsuitable for 32 bit
∂ Beware of cookie monster applications
∂ Check your API design
∂ Avoid large files
∂ Minimize cookie usage in ESI
∂ No SSL support
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83. ∂ Questions? Thank you!