School Server/RIT/XS on XO

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School Server on an XO

(From Spring 2009 Seminar project, see Teacher Reporting.)

A major barrier to achieving our goals is the idea that the School Server needs the ability to be versatile and portable. While some may have resources to dedicate substantial hardware to such a server, others may find themselves with nothing more than the XO laptops. From this stems the idea of running this server on one of the XO laptops via either a USB flash drive, SD card, or the internal NAND hard drive.


When fully installed on an SD card, the base operating system takes up about 1.6GB. There is a small amount of documentation available which is excellent and extremely helpful, but it can be difficult to use at times. Below is a quick break down of what we did and how to replicate it.

How To:

The most helpful website to read before beginning can be found here: Laptop.org's XS-on-XO.

Necessary hardware to replicate our setup includes:
  • XO Laptop
  • Linux Computer with SD Card Reader
    • Can be physical machine or virtual. Also, some things can be done in Windows.
  • SD card which is at least 4GB (We used an 8GB A-DATA SDHC)
Un-compress the image:
Setting Up the Environment

With the SD card connected to the Linux PC:

  • Using a tool of your choice format the SD card to ext2 or ext3 (Linux 83).
    • Gparted was excellent for formating the SD card to ext3, but fdisk would also work.
  • Mark the partition with the boot flag
    • This can be done using gparted, but in several instances errors were experienced. In lieu fdisk works great.
    • To enter fdisk, use
fdisk /dev/sd*1
or
fdisk /dev/mmcblk*p1
  • where * is the letter associated with the SD device and the 1 is the partition. Once in fdisk, use the help to determine the specific command to mark the boot flag. In most instances it will be "a".
  • Next ensure the .img file, uncompressed previously, is accessible by the Linux machines.
  • Use the command,
dd if=OLPC-School-Server-0.5.2-dev01-i386.img of=/dev/sd*1
or
dd if=OLPC-School-Server-0.5.2-dev01-i386.img of=/dev/mmcblk*p1
    • This will take some time depending on the system performance.
  • Use resize2fs to re-size the partition
resize2fs -p /dev/sd*1
or
resize2fs -p /dev/mmcblk*p1
Getting a Developer Key
  • First the XO must have a developer's key!!!
  • The easiest way to go about obtaining this is to boot into the XO's Sugar OS. Open the browse application. Near the bottom right of the home page, there will be a link for "Get a Developer Key".
    • Click this link and on the next page click the "Submit Query." Go through this process again after 24 hours and the key should be available.
    • Upon return follow the directions displayed to download the key.
  • Reboot the XO and tap the "Esc" key to interrupt the booting procedure. At the ok prompt type: 
    ok disable-security
    • The machine will probably reboot. If so, tap the "Esc" key and type the above command again. It may reboot one final time.
    • Upon this reboot tap the "Esc" key again and type the above command a final time. It should print out:
ok disable-security
No wp tag
Booting the XO from the SD

More than likely, this will not work right away, most implementations require some tweaking prior to properly booting.

  • With the SD card inserted in the XO, turn the machine on and press the "Esc" key to interrupt start-up.
  • At the prompt type:
ok boot sd:\boot\olpc.fth
  • It should attempt the boot sequence, but more than likely will fail with a Kernel Panic!!!....error
  • This is almost expected, but it's actually an important step. If you look further up on the screen, you should see an error in regards to mounting the file system.
  • Around this area, you should also see a list of strange numbers (i.e. b102:) followed by devices (i.e. ramdisk...)
  • Find the row for your SD card, it should be labeled something like:
b301:       mmcblk0p1
  • Remember the b301 number.
  • Connect the SD card back to the Linux PC.
  • Open the file /boot/olpc.fth
    • Here's a quick resource on what this is SD Booting.
  • You'll see a line like this:
" ro root=mmcblk0p1 rootdelay=1 console=ttyS0,115200 console=tty0 
rootfstype=ext2 fbcon=font:SUN12x22" to boot-file
  • Change the "root=******" to be the variable recorded earlier.
  • Save the changes and put the SD card back in the XO. Reboot the machine and at the prompt again type:
ok boot sd:\boot\olpc.fth
Post XS School Server Installation Configuration:

The following are commands that were run after installing XS on a Virtual Machine. Idealy, the newly configured SD card can now act as the operating system for the Virtual Machine allowing further versatility. 

yum groupinstall "GNOME Desktop Environment"

edit /etc/inittab and change runlevel from 3 to 5 to startup in Gnome

yum install mysql-server php php-mysql php-mbstring php-gd php-xmlrpc php-imap cvs

service mysqld start
mysqladmin -u root password 'mySecurePassword'
mysql -u root -p
mysql> CREATE DATABASE moodle CHARSET 'utf8';
mysql> exit;
chkconfig mysqld on
--starts sql server; adds root admin user; logs into server and creates DB; 
--turns the service on on boot.

cd /var/www
cvs -z3 -d:pserver:anonymous@eu.cvs.moodle.org:/cvsroot/moodle co -r MOODLE_19_STABLE moodle
--download and install/update with the latest version of moodle

mkdir moodledata
chown -R apache:apache moodle
chown -R apache:apache moodledata
--make directory in /var/www/ and change permissions.

edit the file /etc/httpd/conf/httpd.conf
change DocumentRoot "/var/www/html" to DocumentRoot "/var/www/moodle"
change <Directory "/var/www/html"> to <Directory "/var/www/moodle">
then you must restart the apache server by issuing the command:
service httpd restart
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