If when running vcgencmd on a raspberry pi you get VCHI initialization failed then you need to add the video group to your user. The vcgencmd tool requires you have this group role so without it, it will give VCHI initialization failed.
To add the user group to your user you can run:
sudo usermod -aG video <username>
Where <username> is the user you want to run the vcgencmd command with. This command adds the video group to the the user you specify.
Once you have ran the command any new logins will run the command successfully. Logging out and back into the pi will let you use the command.
Why this problem occurs
This issue happens when you try and use the vcgencmd command with a user that isn’t a member of the video group. This typically happens when you create a new user for the raspberry pi and don’t give it the same groups that the pi user has.
The solution above fixes this by adding the correct video group to the created user.
Today’s blog marks the official start of my Raspberry Pi cluster project. Here I will be documenting the process of assembling, building, and running a small cluster. This blog will include both code snippets, hardware diagrams and the results of various projects using the cluster.
Aims of the project
The Raspberry Pi cluster will be looking into distributed computing from both a hardware and software perspective. Some of the smaller projects planned include:
Youtube playlist syncing and download
Dynamic task management and distribution
MD5 hash calculators
Realtime Reddit thread analysis
But why a Raspberry Pi when it lacks power/ram/etc
Many of the tasks I am planning for the raspberry pi can be run faster and more easily on a single computer. My (5 year old) laptop will have more RAM and processing power than the initial cluster. If I was going for pure power I would run these tasks on a GPU. However the cluster is to experiment with the process of writing and working with a distributed environment.
Part of the reason why I have chosen a raspberry pi is that it is readily available, relatively cheap, and there is a lot of support for it to run Linux. I am planning on running Raspbian Jessie PIXEL to begin with with the possibility of switching to full on Debian or Fedora later.
First steps to a Raspberry Pi Cluster
Already I have one Raspberry Pi 1 Model B Rev 2 which I am going to start developing software for while I collect the other parts. During this time I will search around for a number of raspberry Pi’s. My preference will be for the older versions so that I may purchase more of them cheaply.
Powering them is going to be an investigative point as I dont want to power them using multiple Raspberry Pi cables as these are costly in larger numbers and will occupy lots of power sockets.
As I am expecting to buy a couple different Raspberry Pi versions I am going to look for Micro SD cards which come with adapters. This is because Raspberry Pi 1 B models take a SD card and later models take a Micro SD card.