​GCHQ builds monster Raspberry Pi cloud with OctaPi formation

Britain's GCHQ has built its own Pi cloud consisting of 66 Raspberry Pi Model Bs to teach its engineers about 'scale out' computing.

GCHQ's Octopi Bramble. Image: GCHQ

The's UK spy agency GCHQ says it has developed the world's largest network of Raspberry Pi boards, which it is using to teach its own software engineers the ins and outs of parallel computing.

The spy agency revealed on Wednesday its own Pi 'Bramble', the common term applied to a series of networked Pi boards, which have been used in the past to create mini-supercomputers.

The GCHQ said its Bramble is the biggest ever constructed and the Pi Foundation has confirmed the record.

The creation consists of two head nodes and a cluster of eight networked 'slave' Pi units, each consisting of eight Pi model Bs that GCHQ has dubbed 'OctaPi'. With the two head nodes, its Bramble contains a total of 66 Raspberry Pi devices.

GCHQ is showing off its work at the Big Bang Fair 2015 at the NEC in Birmingham, an event that aims to inspire students with a passion for science and technology.

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The GCHQ's two head nodes make it two Pi devices larger than a Raspberry Pi supercomputer made in 2012 by Professor Simon Cox of the University of Southampton. The computer, then considered the largest Bramble, was held together with Lego pieces.

According to GCHQ, three of its technologists wanted to take a different tack to building Pi Brambles than similar projects thus far, which they found tended be single-purpose machines and weren't built with commercially available hardware components.

The slave component of GCHQ's Pi Bramble include 64 Raspberry Pi model Bs, 32GB of RAM, 1TB of Flash memory, 1,153 controllable LEDs, and eight Gigabit network power over ethernet switches. The LED lights are used to display the system status while PoE was used to cut the number of cables required.

Meanwhile the head nodes consist of one model B each, a 16GB SD card, and a USB hub, and they are battery UPS powered. A wired Ethernet cable is used to control the cluster, while a wi-fi client is used to connect to a local network, and there's a wi-fi access point for local admin devices. Other features include a 128GB solid state disk, a real time clock, touchscreen display, and a camera.

"The GCHQ design is for a commodity-based cluster, consisting of one or more 'blocks' of Pis that can stand alone or be connected together to form a larger cluster. It is designed to be easy to build and service, with a software stack that allows multiple tasks to be run across the available processors using multiple technologies," the agency said.

The GCHQ says it built from scratch the control system to manage its OctaPi formation and after three iterations, settled on a design based on Node.js, Bootstrap, and Angular.

Although it's been three years since the last Bramble record was broken, GCHQ expects its record to be snatched away in no time.

"We fully expect others to beat our record-breaking cluster before too long, but hope that it will inspire young people to get involved in the study of science-based subjects and take advantage of the exciting career opportunities such qualifications can offer," a GCHQ spokesperson said.

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