Slide 1
Slide 1 text
By Thijs Feryn
Slide 2
Slide 2 text
3 statements
Slide 3
Slide 3 text
Slow websites suck
Slide 4
Slide 4 text
Web performance is an
essential part of the user
experience
Slide 5
Slide 5 text
Down
Slowdown ~ downtime
Slide 6
Slide 6 text
Performance
!=
Scalability
Slide 7
Slide 7 text
Performance: speed
Slide 8
Slide 8 text
Scalability: constant speed
with increasing load
Slide 9
Slide 9 text
Improve
Slide 10
Slide 10 text
Hi, I’m Thijs
Slide 11
Slide 11 text
I’m
@ThijsFeryn
on Twitter
Slide 12
Slide 12 text
I’m an
Evangelist
At
Slide 13
Slide 13 text
I’m a
at
board member
Slide 14
Slide 14 text
What’s the problem?
Slide 15
Slide 15 text
Infrastructure
Slide 16
Slide 16 text
Code
Slide 17
Slide 17 text
The
context
Slide 18
Slide 18 text
✓Tremendously popular
✓Even the big boys use it
✓Not the best code
✓It does the job
✓Powered by the LAMP stack
The context: Wordpress
Slide 19
Slide 19 text
Identify slowest parts
Slide 20
Slide 20 text
Optimize database
Slide 21
Slide 21 text
✓More RAM
✓Faster disks
✓More database servers
✓Master-slave replication
✓Read/write splitting (HyperDB)
✓Query/Object caching (Redis)
Optimize database
Slide 22
Slide 22 text
Optimize runtime
Slide 23
Slide 23 text
✓More RAM
✓Faster disks
✓More/faster CPUs
✓More servers
✓OPCache
✓PHP-FPM
✓Recent PHP version
✓HHVM or PHP 7?
✓Nginx or Apache?
Optimize runtime
Slide 24
Slide 24 text
Optimize code
Slide 25
Slide 25 text
After a while
you hit the limits
Slide 26
Slide 26 text
Optimize database
Optimize runtime
A
void
A
void
Slide 27
Slide 27 text
Don’t
recompute
if the data
hasn’t
changed
Slide 28
Slide 28 text
Cache
Slide 29
Slide 29 text
3 x 2 = ?
Slide 30
Slide 30 text
✓WP Supercache
✓W3 Total Cache
✓Wordfence Cache
✓WP Rocket
Wordpress caching?
Slide 31
Slide 31 text
✓WP Supercache
✓W3 Total Cache
✓Wordfence Cache
✓WP Rocket
Wordpress caching?
Forget
about
those*
*sometimes
Slide 32
Slide 32 text
Varnish
Slide 33
Slide 33 text
Normally
User Server
Slide 34
Slide 34 text
With Varnish
User Varnish Server
Slide 35
Slide 35 text
No content
Slide 36
Slide 36 text
Stores
HTTP output
in memory
Slide 37
Slide 37 text
Respects
cache-control
headers
Slide 38
Slide 38 text
For page
caching
Slide 39
Slide 39 text
Could be
thousands of
times faster
Slide 40
Slide 40 text
There are rules
Slide 41
Slide 41 text
✓Only GET & HEAD
✓No authorization headers
✓No cookies
✓No set-cookies
✓Valid cache-control/expires
headers
When does Varnish
cache? Some rules …
Slide 42
Slide 42 text
PROBLEM !!!
Slide 43
Slide 43 text
Dealing
with
state
Slide 44
Slide 44 text
Varnish
Configuration
Language
Slide 45
Slide 45 text
✓ 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
Slide 46
Slide 46 text
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, "\?.*$", "");
ban("obj.http.X-Req-URL-Base == " + req.url + " && obj.http.X-Req-Host == "
+ req.http.host);
}
Slide 47
Slide 47 text
Make Varnish
aware of
Wordpress
Slide 48
Slide 48 text
https://gist.github.com/
ThijsFeryn/
aabd6d7ed425fb6614279e836d
9848c5
Download
VCL here
Slide 49
Slide 49 text
Control
Time
To
Live
Slide 50
Slide 50 text
sub vcl_backend_response {
set beresp.ttl = 3h;
}
Control Time To Live
Slide 51
Slide 51 text
Header set Cache-Control "public, max-age=3600"
Header set Cache-Control "public, s-maxage=2592000"
Control Time To Live
Apache
.htaccess
Slide 52
Slide 52 text
add_header Cache-Control “public, s-maxage=3600;”
Control Time To Live
Nginx
vhost
config
Slide 53
Slide 53 text
Purging
Slide 54
Slide 54 text
https://wordpress.org/
plugins/varnish-http-purge/
Plugin that
hooks into the
CMS
Invalidates
cache
Slide 55
Slide 55 text
Performing the purge
curl -XPURGE "http://example.com/bla"
Wordpress
does this
internally
Uses VCL
logic at the
Varnish end
Slide 56
Slide 56 text
URLs to purge
/
/category/uncategorised/
/author/admin/
/hello-world/
/feed/atom/
/feed/rdf/
/feed/rss/
/feed
/comments/feed/
/hello-world/feed/
Example
Slide 57
Slide 57 text
Debugging
Slide 58
Slide 58 text
sub vcl_deliver {
if (obj.hits > 0) {
set resp.http.X-Cache = "HIT";
} else {
set resp.http.X-Cache = "MISS";
}
}
Debugging
Slide 59
Slide 59 text
Varnishlog
Varnishtop
Varnishncsa
Monitor
Varnish
behaviour
Slide 60
Slide 60 text
What about SSL/TLS?
Slide 61
Slide 61 text
Varnish does
not support
SSL/TLS
Slide 62
Slide 62 text
You have to terminate
SSL/TLS yourself
Slide 63
Slide 63 text
Varnish 4.1
supports
PROXY
protocol
Slide 64
Slide 64 text
✓HAProxy
✓Hitch
✓Stud
✓Nginx
SSL offloader
Slide 65
Slide 65 text
Offload SSL
User
Varnish
Server
SSL offloader
Slide 66
Slide 66 text
User
SSL offloading & load balancing
Varnishes
Servers
Load balancer
+ SSL offloader
HAProxy
loadbalancers
Slide 67
Slide 67 text
Make Wordpress
protocol aware
define('FORCE_SSL_ADMIN', true);
if ($_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https'){
$_SERVER['HTTPS']='on';
}
Header set
by SSL
offloader
Slide 68
Slide 68 text
What about
Slide 69
Slide 69 text
✓Object caching
✓Session storage
✓Stanalone
✓Replicated
✓Clustered
Redis
Slide 70
Slide 70 text
Consistent
state
When
loadbalancer
switches to
another
server
Slide 71
Slide 71 text
Cheers, hope
this helps!
Slide 72
Slide 72 text
Don’t
recompute
if the data
hasn’t
changed
Slide 73
Slide 73 text
Varnish
Slide 74
Slide 74 text
No content