Raspberry PI 2 Cluster Case pt2

This is the second post of a series about Raspberry PI 2 BigData cluster case.

  1. Raspberry PI 2 Cluster Case pt1
  2. Raspberry PI 2 Cluster Case pt2
  3. Raspberry PI 2 Cluster Assembly Tutorial
  4. Build Hadoop Cluster with 5 clicks

 

From Raspberry PI 2 Cluster Case pt1, I drew up a rough sketch with certain goals I set out to. They are,

  1. Able to fit in 6 RPI2 in a small, contained volume.
  2. Has to be stackable.
  3. Able to fit in a power supply and a 8 port network switch for the 6 RPI2.
  4. Able to cool off the cluster with no fan.
  5. Has to be cheap.

Prototyping

I then cut out an Acrylic panel at a near laser shop.

Two RPI2 on a cluster panel

The panel have two big round holes for ventilation, 8 holes for RPI2 mounts, and 8 more holes for pillar screws.

Once you put pillars, it looked like this.

Pillar Screws and mounts on a cluster panel

I put a giant square hole in the center to put a USB charger as power supply. You can see the two big round holes for heat ventilation.

At this point, I was terrorized with fact that I could not put a USB-to-MicroUSB cable to the center USB charger. You see the square hole is completely closed? I found that the panel blocked the USB charger’s USB socket, rendering the charger useless. What a bummer…

Gah! No way!

Of course, my happy story did not end there. I then put a RPI to see if it fitted in. To my disappointment, the mount was just too high. You see USB ports sticks to the upper level panel, and there is space underneath the RPI? That’s bad.

Long Mount
High Mountain

In fact, the mount was just too Long. I figured a mount should be around 4~5 mm in length. On top of that, I put one too many pillar screws. I had to use only the minimum number of them to maintain structure strength.

All in all, three problems.

  1. Entrance to USB charger.
  2. Appropriate Mount screw.
  3. Minimum # of pillar screws.

The Final Result

After Fixing three issues above, I now have this.

6 Nodes RPI2 Cluster
6 Nodes RPI2 Cluster
pt-9
The cluster from different angle.

Those USB-to-MicroUSB cables are only 30 centimeters in length. They still stand out and take up quite a bit of space. Does anyone know where I can get a shorter cable?

8 Ports Network Switch at the bottom stack
8 Ports Network Switch at the bottom stack

Of course You can put the entire cluster on your desk.

A cluster on a desk
A cluster on a desk

Assessment

I’ve run the cluster closed to two months so far. I’ve experienced neither heat issue nor performance hit. No single node has gone down while I’m running Apache Spark/Hadoop in cluster mode. It has been amazingly stable and easy to operate. Although there are few more issues I like to fix up later. (Especially the USB charger cable.)

Let’s move on to JAVA on Raspberry PI next time!
 

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17 thoughts on “Raspberry PI 2 Cluster Case pt2

  1. Thanks for sharing. I’ve been wondering if it would be possible to run a Hadoop cluster of my own using Raspberry Pi, but I haven’t had the time to try or the resources to risk failing. I’m going to file this away and maybe give it a go some time down the road.

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  2. I would shorten the cables you have by simply cutting them and solder on new USB cables. Think you could make it a bit smaller by removing the casing of the switch, allowing less heat to be encased. Other than this it looks amazing! Good job.

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  3. Why not supply through the GPIO header? You could cut off the USB cables at a convenient length and solder (ugly) or get a small switching voltage supply and branch out with square post plugs..

    Liked by 1 person

  4. You can power the Raspberry Pi by hooking directly into the 5V and GND pins on GPIO, bypassing the need for USB power. That should reduce your power supply size, since you won’t physically need 6 USB-A slots. It should also help with the layout since you’ll get rid of the USB jutting off of the sides.

    Liked by 2 people

  5. You can take up the slack in the cables by rotating the raspberry pi’s 180 degrees. The cables will then run around the outside, past the short side, and to the power source.

    Liked by 1 person

    • Brian, That’s brilliant! I in fact tried once, and it looks a bit clumsy but it does not requires the 90-degree-turned special cable.

      I’ve been thinking to improve the current design with common, more available components in the market as well. The current design requires to use the special cable and that’s bit of headache for lot of folks.

      Thanks you for providing a tip.

      Like

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