My Virtualization and Cloud Computing resource blog
Archive for November, 2012
Alarm Box – Part III
Nov 17th
As I received many positive reactions on my Analog Alarm Box to monitor your VMware vSphere environment, I decided for the first “finalized” product to not include the split-flip display, as I still need to work out a lot of things to be able to “mass” produce it. The slim box will have 4 analog meters and you will be able to decide yourself what each meter displays. Like 4x the CPU usage of 4 different clusters or the CPU and Memory Usage of 2 clusters, storage consumption, or what ever.
I am adding a 2 line 16 chars LCD display in the box, that can show the names of the meters that are being displayed and can also display alarm notifications. The box will get a buzzer, for when an alarm condition is met. You will be able to configure and setup the box using the build-in webserver.
I will make easy kits that people will be able to assemble that will contain everything but the Raspberry PI board, including a breakout board will all the electronics that can just be put on the header pins or the Raspberry PI, 4x the analog meters, the LCD display, buttons and the wooden box itself.
The Alarm Box – Part II
Nov 8th
I know this is supposed to be a weekend project, but I had some spare time on my Thursday evening 
So here an update on my vSphere Alarm Box.
I received my analog panel meters this week. Instead of them displaying 0 to 5v I created some new face plates for them using my automatic paper cutter so they can display CPU and Memory consumption. These meters are very easy to control by using a PWM signal, but the challenge is that the Raspberry PI only has one PWM port. So I decided I want to use an arduino for this. Making the Raspberry PI talk to the arduino is fairly straight foward. I am using I2C, but as the arduino uses 5v for its logic circuits and the Raspberry 3.3v I had to build a small level shifter to allow both both safely to communicate over I2C.
Everything now connected hardware wise, now I just had to make the meters work, displaying the right information from VC. I am writing my code in PHP and already had last weekend written the PHP code to use the QueryPerf API call to retrieve the last 5 minute average for CPU and memory of my cluster. But PHP does not allow me to send I2C calls, so I had to write an extension module for PHP to enable me to do this. As I never had written an PHP module, thanks to google, this did not take too long
So there it is.. IT IS WORKING Every minute Raspberry PI uses QueryPerf to retrieve information from VC. Using my PHP I2C extension it sends an I2C call, via the level shifter to my arduino. The arduino uses the value received via I2C to set the PWM for the specific pins and tha dah… working 
Weekend Project: The VMware Alarm Box
Nov 4th
As I am happy with the progress my little project is taking, I thought I would share with you all what I am working on. I like to make physical things and one of the things I have been developing is and old-school split-flap display (You know from those boards in old train stations). Some day I like to make 140 units, so I can have a live twitter board in my living room, but for now I have settled with one
I needed a purpose for my display… So I thought I would make a vSphere / Datacenter Alarm Box, based on some good old-school components. At first I wanted to use my good trusted Arduino, but unfortunately it does not support HTTPS/SSL (not powerful cpu to deal with the encryption). And if I want to make an alarm box for the vSphere environment, it need to at least be able to get all kinds of info from your virtual center server. So I ordered an Raspberry PI, a new open hardware platform like the Arduino, but based on a much more powerful processor and running linux (and all this for $30!).
After some tinkering around this weekend, I was able to get my Raspberry PI to talk to Virtual Center using the official APIs So I can now get alarms, check for other things like retrieve the CPU and Memory Usage of the entire cluster (last 5 minute average). So besides using only my split-flap display, I decided to also build 2 analog panel meters in my box, as these measure 0 to 5volt, I can easily control them just using PWM, so they can show (in percentage) at any time the CPU and Memory consumption of your Cluster.
I am not 100% finished yet, but all the components are starting to fall in place So I thought I would share with you and of course if you have any great ideas about what this Alarm box should monitor/detect, please let me know. I am also putting in a 7-segment display, to show the amount of running Virtual Machines.
Here a video of the split-flap display part I have build for testing.
Let me know if you like this project and if you maybe someday want an Alarm box like this, as I can consider making a few.
I plan on making the face plate from aluminum or really nice oiled wood. Their will be a serine on top of the box, that can go off on certain events you selected, with just the light and/or sound going off. So they box will be completely stand-alone (NO PC required) and will be about $75 in parts. Just plug in power and ethernet, it will run a webserver that you can connect to to configure it.
to be continued…
