Service/mirrors
Introduction
A content delivery network or content distribution network (CDN) is a system of computers containing copies of data, placed at various points in a network so as to maximize bandwidth for access to the data from clients throughout the network. A client accesses a copy of the data near to the client, as opposed to all clients accessing the same central server, thereby causing a bottleneck near that server.
Mirrorbrain, Bouncer, Fedora Mirror Manager, and Cacheboy are four possible choices for scaling up the Sugar Labs content delivery net work. Long term, Cacheboy looks like it might be the best fit for Sugar Labs, but the project must become more stable before becoming Sugar Labs primary CDN. Bouncer is currently being used as successfully by Mozilla. But development ended at the end of 2008. Mozilla is currently investigating Mirrorbrain. Mirrorbrain looks promising.
Goals
- Reduce bandwith at primary download server.
- Improve quality of service for users.
- Move content closer to users.
Mirrorbrain
Mirrrorbrain is used by several major project including opensuse and openoffice. It is quite stable, under activate development, and well documented,
Installation
The following Recipe for installing mirrorbrain on ubuntu 9.04 is based on information at http://mirrorbrain.org/docs/ .
Install LAMP Server
Install a standard Ubuntu LAMP server
Download mirrorbrain
wget http://mirrorbrain.org/files/releases/mirrorbrain-2.10.0.tar.gz
tar xzf mirrorbrain-2.10.0.tar.gz
Install python dependencies
sudo apt-get install python-sqlobject python-psycopg2
The python cmdln module is not prepackaged for Ubutnu so it must be installed manually.
wget http://cmdln.googlecode.com/files/cmdln-1.1.2.zip
unzip cmdln-1.1.2.zip
cd cmdln-1.1.2
sudo python setup.py install
Install perl dependencies for scanner
The mirrorbrain scanner is written in perl and requires several dependencies.
sudo apt-get install libconfig-inifiles-perl libwww-perl libdbd-pg-perl libdatetime-perl libdigest-md4-perl
Build, Install, and Configure Apache2 modules
Mirrorbrain requires several Apache modules, several of which must be built manually. Apache modules are built and installed using apxs2. (APache eXtenSion tool) Apxs2 is in the apache2-threaded-dev package.
sudo apt-get install apache2-threaded-dev
Install and Configure mod_geoip
Mod_geoip is available as a prebuilt package.
sudo apt-get install libapache2-mod-geoip libgeoip-dev
Mod_geoip must be configured to find the the GeoIP data set.
sudo sh -c "cat > /etc/apache2/mods-available/geoip.conf << EOF
<IfModule mod_geoip.c>
GeoIPEnable On
GeoIPOutput Env
GeoIPDBFile /var/lib/GeoIP/GeoIP.dat MMapCache
</IfModule>
EOF
"
Download GeoIP data set
wget http://geolite.maxmind.com/download/geoip/database/GeoLiteCountry/GeoIP.dat.gz
sudo apt-get install gzip
gunzip GeoIP.dat.gz
sudo mkdir /var/lib/GeoIP
sudo cp GeoIP.dat /var/lib/GeoIP/GeoIP.dat
Enable module.
sudo a2enmod geoip
Restart Apache
sudo /etc/init.d/apache2 restart
Install and Configure mod_form
Mod_from must be build from sctatch.
FIXME correct directory
Download source
wget http://apache.webthing.com/svn/apache/forms/mod_form.c
wget http://apache.webthing.com/svn/apache/forms/mod_form.h
build mod_form
sudo apxs2 -cia mod_form.c
create loader
sudo sh -c "cat > /etc/apache2/mods-available/form.load << EOF
LoadModule form_module /usr/lib/apache2/modules/mod_form.so
EOF
"
Enable module.
sudo a2enmod form
Restart Apache
sudo /etc/init.d/apache2 restart
Configure mod_dsd
configure mod_dsd
sudo sh -c "cat > /etc/apache2/mods-available/dbd.conf << EOF
<IfModule mod_dbd.c>
DBDriver pgsql
# note that the connection string (which is passed straight through to
# PGconnectdb in this case) looks slightly different - pass vs. password
DBDParams "host=localhost user=mb password=12345 dbname=mb_sugar connect_timeout=15"
</IfModule>
EOF
"
Enable module.
sudo a2enmod dbd
Restart Apache
sudo /etc/init.d/apache2 restart
Install and configure mod_mirrorbrain
Build mod_mirrorbrain
sudo apxs2 -cia mod_mirrorbrain.c
create module loader
sudo sh -c "cat > /etc/apache2/mods-available/mirrorbrain.load << EOF
LoadModule mirrorbrain_module /usr/lib/apache2/modules/mod_mirrorbrain.so
EOF
"
Enable module.
sudo a2enmod mirrorbrain
Restart Apache
sudo /etc/init.d/apache2 restart
Build and Install helper programs
build and install geoiplookup
gcc -Wall -lGeoIP -o geoiplookup_continent geoiplookup_continent.c
sudo cp geoiplookup_contintent/usr/bin/geoiplookup_continent
Install scanner
sudo cp ../tools/scanner.pl /usr/bin/scanner
Install postgres
sudo apt-get install postgresql-8.4
Create the postgresql user account and database
Switch to user postgress
sudo su - postgres
Create user
createuser -P mb
Enter password for new role:
Enter it again:
Shall the new role be a superuser? (y/n) n
Shall the new role be allowed to create databases? (y/n) n
Shall the new role be allowed to create more new roles? (y/n) n
Create database
createdb -O mb mb_sugar
createlang plpgsql mb_sugar
Exit user postrges
exit
Edit host-based authentication
add line 'local mb_sugar mb trust' to the end of pg_hba.conf
FIXME should not be trust on production machine
sudo vim /etc/postgresql/8.4/pg_hba.conf
Start the potgres server
sudo /etc/init.d/postgresql-8.4 restart
Import intial mirrorbrain Data
Import table structure, and initial data
psql -U mb -f sql/schema-postgresql.sql mb_sugar
psql -U mb -f sql/initialdata-postgresql.sql mb_sugar
Create mirrorbrain user and group
sudo groupadd -r mirrorbrain
sudo useradd -r -g mirrorbrain -s /bin/bash -c "MirrorBrain user" -d /home/mirrorbrain mirrorbrain
Create mirrorbrain.conf
sudo cat > /etc/mirrorbrain.conf << EOF
[general]
instances = samba
[samba]
dbuser = mb
dbpass = 12345
dbdriver = postgresql
dbhost = 127.0.0.1
# optional: dbport = ...
dbname = mb_sugar
[mirrorprobe]
mailto = dfarning@sugarlabs.org
Set permission and priviglies
sudo chmod 0604 /etc/mirrorbrain.conf
sudo chown root:mirrorbrain /etc/mirrorbrain.conf
Test mirrorbrain
./mirrorbrain.py
Create VirtualHost
sudo cat > /etc/apache2/sites-available/mirror << EOF
<VirtualHost your.host.name:80>
ServerName samba.mirrorbrain.org
ServerAdmin webmaster@mirrorbrain.org
DocumentRoot /srv/samba/pub/projects
ErrorLog /var/log/apache/samba.mirrorbrain.org/logs/error_log
CustomLog /var/log/apache/samba.mirrorbrain.org/logs/access_log combined
<Directory /srv/samba/pub/projects>
MirrorBrainEngine On
MirrorBrainDebug Off
FormGET On
MirrorBrainHandleHEADRequestLocally Off
MirrorBrainMinSize 2048
MirrorBrainHandleDirectoryIndexLocally On
MirrorBrainExcludeUserAgent rpm/4.4.2*
MirrorBrainExcludeUserAgent *APT-HTTP*
MirrorBrainExcludeMimeType application/pgp-keys
Options FollowSymLinks Indexes
AllowOverride None
Order allow,deny
Allow from all
</Directory>
</VirtualHost>