User:Holt/XS Community Edition/0.1/Project Specifications
School Server - Community Edition 0.1 Project Specifications
Executive summary
The school server is very similar in concept to a standard home wireless router. In everyday usage it provides various services which extend capabilities of the connected laptops while being totally transparent to the user.
These services can include: 1. Security – XO related security services. 2. Network connection – various services similar to what you would find in a home router. 3. Presence server – Augments sugar's native collaboration functionality. 4. Web filtering – Enables schools to comply with local legal restrictions on internet access for children. 5. Content management -- ???
Reference User
For the purposes of this document, I am taking OLPC-AU as the reference user. As a result this design might not apply in all situations in all deployments. This imposed limitation will make it is easier to design and develop a working reference implementation.
If we use proper modularity it will be relatively straightforward to abstract the design and implementation to meet other use cases.
Hardware
To reduce inventory and maintenance costs, the target hardware for the school server will be recent XO laptop. Due to hardware limitations on early XO's, design and implementation of a fully functional server becomes difficult on them.
In common usage, the XO may be augmented by two off the shelf USB devices: 1. External hard drive – Allows the server to provide additional storage capabilities. 2. Network connector – Allow the server to offer internet access to connected XO's.
Using this strategy it is simple for a deployment to inventory and maintain school servers. A school can replace a school server by taking a standard XO and running a single server setup command.
NOTE: Limiting the hardware to XO simplifies the implement and testing process because their fewer possible configurations to deal with. Supporting multiple platform would be a good for a future release.
Deliverable
The final deliverable from the community will be an image which can be flashed onto a laptop by deployment support staff.
At initial server 'power on' the support staff or teacher will be greeted by a simple GUI to do initial configuration.
A single RPM or meta package necessary to convert a standard XO into a School Server should also be possible.
NOTE: Projects tend to emphasize packages while Products tend to emphasize images.
OS
To keep things simple and consistent the school server will run the same OS as the classroom laptops. Both teachers and support staff will already be familiar with the system.
NOTE: Limiting the deliverable to single OS variant meets the requirement to work on a XO while limiting complexity. Future releases can add additional Operating Systems.
User Interface
Browser based GUI. – The primary configuration tool will be a browser based GUI. This technology is well understood by developers. Many end uses have familiarity with Browser based setup.
A browser based allow admin from three physical proximity distances: 1. On screen. Initial setup and admin of security sensitive services can be limited to on screen. 2. On site. Subsequent management of non security sensitive services can be done by a teacher or local admin logging in to the machine. 3. Remote. Deployment level support staff can log in and remotely maintain and monitor services.
Remote automation – There are several system such as CFEngine and puppet which enable remote management. While not immediately required by AU it is highly desirable by large deployment.
Command Line – Command line configuration should be discouraged at all levels. Target users are often not familiar with the linux system administration. Initial setup or fixing a problem with their server is not a good time to introduce system administration skill.
NOTE: Is is possible or useful to create a Sugar base configuration tool?
Modular design
One of the key design criteria of all successful community based projects is modularity. The original XS suffered because Wad and Martin took used monolithic design overcome hardware limitations on the XO-1. The improvements in the XO-1.75 and XO-4 allow for the potential inefficiencies of modularity.
The core server will contain 3 components: 1. Initial setup and configuration. 2. GUI framework. 3. Core services with GUI panels. The core server will be extended via extended services.
Initial Setup
Service: Network setup Purpose: Provider: xs-setup-network
GUI Framework
The GUI permits permits configuration of the network interfaces: Already existing network and internet gateway Choose fixed ip and gateway use dhcp automatic assignment Establish a gateway to the internet, setup WAN and LAN: Use dhcp to setup WAN Manually setup WAN address, gateway, dns Use either of the above methods to set up LAN It permits enabling and disabling of services -- supported and enabled for this release are dhcp, iptables/gateway, named, ejabberd.
Core Services
Service: Dynamic Host Configuration Protocol Purpose: Schoolserver and clients need to be on same subnet. Provider: dhcpd
Service: Iptables -- Network Address Translation (NAT) Purpose: Permits all XO’s to access the internet Provider: gateway
Service: Internet domain name server Prupose: Provider: named
Service:Jabber server (AnnaS) Purpose: collaboration > 15 clients needs to work Provider: ejabberd
Extended Services
Service: proxy server and web cache (XavierC) Purpose: bandwidth, web-filtering, web-monitoring Provider: squid
Service: Content filtering (TimM??) Purpose: age-appropriate surfing, legal compliance, religious risks Provider: dansguardian
Service: Backup of student work and restore (JerryV, SameerV, GeorgeH) Purpose: also for stats/metrics, with incumbent surveillance risks Provider: idmgr
Service: (JerryV, GeorgeH) Purpose: Journal submissions to teacher, academic record (homework etc) Provider: WebDAV
Service: (DSD, GeorgeH) Purpose: remote upgrading/admin of XS servers (semi-automated) Provider: Puppet
Service: (GeorgeH, GeraldA) Purpose: local distribution/replication of Sugar Activities etc Provider: pdsh
Service: Book server (SameerV, AlexK, GeorgeH struggling!) Purpose: compete with Khan Academy? Provider: pathagar