Help Activity refresh/Chapter/XS school server

Hardware

The selection of the school server hardware should take into account a number of factors:

• How many XO's will be connected to the school server at a given time, and over the period of the school term (say, a semester or year)?
  • A low power 30 watt Atom processor-based server, such as the Solid Logic http://www.logicsupply.com/products/atom_jt01s can support up to 60-100 students. This server has 1 Gb of RAM and about 2 GByte of disk space for every XO
  • An 80 watt core i3 64bit processor might support 150-300.
  • A top of the line core i7 quad or itanium processor might need 4 Gbyte, 1.5TB, and can handle 300-500 XO's.
• Adequate power for a school server is often difficult to achieve.
  1. How much power is available during a 24 hour period? Will the server be connected to the grid? Is the grid reliably on during school hours? If not, how big does the battery need to be to supply power during school hours? If power is not dependable enough during a 24 hour period, maybe solar power will be required.
  2. The power consumption of the server times the number of hours in the school day will determine the number of watt-hours that must be stored in a deep-cycle storage battery. Batteries are usually rated in Ampere-hours. A 12 volt battery with a 100 Amp-hour capacity, holds 1200 watt-hours. Batteries last longer if they are cycled through only about 50% of their total capacity. So you can use about 600 watt-hours from a 100AHr battery. This can keep a 120 watt server alive for 5 hours, or a 30 watt server for 20 hours.
  3. An intelligent Uninteruptible Power Supply (UPS), capable of communication with the server (typically via serial or USB cable), should be installed so that the server can properly shut itself down, when battery power is almost exhausted. In addition to the school server itself, networking hardware must be purchased. For purposes of planning, there should be one access point (AP) for each 50 XO's. With multiple AP's, there will need to be a 5-8 port ethernet switch installed close to the school server.

Access points can be configured to use 11 channels, but really only 3 channels are non-interfering (channels 1,6,and 11).

Installation

CentOS6.2 minimal method

Note: This method requires you to be connected to the Internet to download and install extra packages.

Download CentOS6.2 minimal install iso from centos.org and check md5sum

Install unetbootin (http://unetbootin.sourceforge.net/)

Run unetbootin to create bootable usb stick from iso.

IMPORTANT!!! Also copy iso to root directory of usb stick. Without the iso on the stick, the install fails when it looks for media on a CD-ROM, any your server may not have a CD drive.

Boot server machine from USB stick using: "default" option. In the "from" option (hard drive, CD/DVD, NFS etc.) pick: "hard drive" Which disk contains install medium: usually /dev/sda1

Once installation is done, reboot server.

eth0 isn't up by default.

1. ifconfig eth0 up

Get a DHCP lease

1. dhclient eth0

Add EPEL repository.

1. wget epel-release-6-5.noarch.rpm
2. rpm -ivh epel-release-6-5.noarch.rpm

Add OLPC XS list of repositories.

1. rpm -ivh "http://dev.laptop.org/xs/repos/stable/olpc/xs-0.7/i386/xs-release-6-1.noarch.rpm"
2. yum groupinstall "OLPC XS"

Setup server domain

1. xs-setup olpcsf.org  ; use <your.domain.name> instead of "olpcsf.org"
2. reboot

Setup network with only one Ethernet port.

xs-setup-network

1. reboot

The server is now functioning and XOs can register The first XO to register becomes the admin.

Add a USB-to-Ethernet dongle and plug into WAN

Must run xs-setup-network and then reboot because we added a USB ethernet dongle (WAN connected) and now XOs have internet access, but no name resolution!

Step 15b (optional):

Had to add forwarders section to /etc/named-xs.conf.in Add the following line between the "options" opening '{' and closing '}': forwarders {<dns-server1>; <dns-server2>; ..};

1. xs-setup-network

Reboot.

Management

• The school server can be managed through the Browse activity on the XO. Note: The very first XO that registers with the school server gains status of the admin user. When using the browse activity on this XO, one can log into the server directly and gain admin access on Moodle.

• First XO login

• Browse logs in via a passthrough (we do not see the login prompt)

• screenshot

• Features on the web interface: 1) Moodle (curricular) 2) Admin (backup, restore, theft deterrence, presence, etc)

Monitoring

Monitoring via Moodle: Moodle logs

Adding additional services such as Munin.