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FreedomCenter_-_LAMP_System
The Free Network Foundation operates a substantial number of web properties in our MCI facility. We've
deployed a very robust/scalable system to support a large scale, read heavy HTTP workload.
Contents
• 1 Overall web flow
• 2 Load balancing and content/code
caching
♦ 2.1 Varnish
♦ 2.2 APC
♦ 2.3 Memcached
• 3 Apache server
♦ 3.1 Modules in use
♦ 3.2 vhosts
• 4 MySQL
♦ 4.1 Caching
♦ 4.2 Databases
♦ 4.3 Replication
Overall web flow
The overall web flow, depicted in the diagram below, begins when web traffic hits our network edge. It flows
from our edge router (wan01), through layer two switching (sw01) to the machine that hosts our virtualized
computer environment (vm01).
At this point, it flows into a virtual machine called lamplb (for load balancer), which caches and
loadbalances. Details of this configuration, are described in the section 'Varnish', below. Varnish provides a
cache for all static HTTP objects (html/css/js) from those virtual machines that host the applications
themselves.
The majority of applications are able to share a VM called 'lamppublic', which does some further caching,
described below. Applications that require a specialized environment (Ruby on Rails for Chili, for instance)
are hosted on their own machine.
A unified, optimized, replicated and backed up sql server, described in the 'MySQL' section, backs all
services. Storage for all VMs is served from the storage array (stor01), which is documented in
FreedomCenter_-_Storage.
Load balancing and content/code caching
Varnish
We use varnish for caching all of our HTTP content and routing traffic to back end servers. It lives on
lamplb.corp.thefnf.net (10.250.4.38) and it's configuration can be found in /etc/varnish/default.vcl
Here is a configuration snippet:
#Define various real servers...
backend default {
.host = "10.250.4.40";
.port = "80";
}
Contents
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FreedomCenter_-_LAMP_System
backend chili {
.host = "10.250.4.32";
.port = "80";
}
<snipped>
sub vcl_recv {
if (req.http.host == "chili.freenetworkfoundation.org") {
set req.backend = chili;
return (lookup);
}
if (req.http.host == "learn.freenetworkfoundation.org") {
set req.backend = canvas;
return (lookup);
}
<snipped more of the same>
then the default
else {
set req.backend = default;
}
}
If you need to add a new web property that isn't on the lamppubic system, just create a new backend and
update the vcl_recv stanza.
At this time, it appears that a web front end for Varnish may be a proprietary add on. One can use varnishtop
/ varnishstat if they need information on varnish performance.
APC
We use APC on lamppublic. APC is a PHP object cache/compiler. Provided that you are on the VPN, you
can view cache statistics at
http://lamppublic.corp.thefnf.net/apc
Memcached
Wordpress/Mediawiki are configured to use memcached, which lives on the lamplb box. You can hit that via
telnet and gather stats:
[1] root@lamplb> echo "stats" | nc 10.250.4.38 11211
~
[1] root@lamplb> echo "stats" | nc 10.250.4.38 11211 | grep bytes_
STAT bytes_read 6911958
STAT bytes_written 5470422
^C
[130] root@lamplb>
Varnish
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FreedomCenter_-_LAMP_System
Apache server
We use Apache for all our production sites. It's a stock Debian package configuration, except for enabling a
few modules (listed below).
Modules in use
• mod_rewrite
• mod_pagespeed gpl module from Google which implements the same things server wide that
w3tc/minify does for just wordpress
vhosts
Here is a list of our current virtual hosts:
root@lamppublic> date && ls /etc/apache2/sites-enabled|grep -v legacy
Wed Sep 26 16:32:52 CDT 2012
apc
bookmarks
commons
credman
crm
dispatch
documents
fnm
forum
frontpage
hr
incbits
incbits-test
kb
legwatch
mblog
meetings
owa
pastebin
photos
prodmanuals
racktable
sharing
snetinsight
social
staticbits
support
ushadi
video
webstats
xibo
root@lamppublic>
~
(grep -v legacy is to remove our vhosts for redirecting from freenetworkfoundation.org to thefnf.org).
MySQL
Apache server
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FreedomCenter_-_LAMP_System
Caching
Databases
Replication
FreedomCenter Documentation (edit)
High-level: Landing Page - Overview - System - Migration
Sites: MCI - ATX - DFW
Subsystems: Network - Compute - Storage - Out of Band
Functions: LAMP - DNS - Monitoring - SSL - LDAP
Catalogs: Public Services - Administrative Services - Walkthroughs
Caching
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