Sunday, August 23, 2020

K3s Raspberry Pi 4 Cluster

Do you have an interest in Raspberry Pis and cluster computing? Me too! 


One thing that I have enjoyed about building the Raspberry Pi cluster is that it's inexpensive to build up over time. 

I bought the Raspberry Pis and the PoE hats from Canakit, and everything else was bought from Amazon. Amazon had higher prices for the Raspberry Pi PoE hat, and didn't have a Raspberry Pi 4B 8GB board available when I first started buying the parts. 

Here is a list of what I bought for the cluster. 

Part My Choice Qty Links
Case Cloudlet Cluster Case 1 Amazon
Raspberry Pis RPi 4B+ 8GB 5 Canakit
PoE Hats Raspberry Pi PoE HAT 5 Canakit
SD Cards SanDisk 128GB microSDXC 5 Amazon
Network Switch  TP-Link 8 Port PoE Switch  1 Amazon
Network Cables Cat7 1FT Multi-Color 1 x 5pk  Amazon


I used the Cloudlet Cluster Case by C4Labs.

Very tiny, but fulfilling, RPi cluster.

It practically hums like the WOPR!

I found the case by searching on Amazon for "Raspberry Pi Cluster Case', and the Cloudlet Cluster Case was the first result I saw that I really liked. I like the look of the stackable cases, but the Cloudlet Cluster Case reminded me of a very tiny computer rack - it felt right.

The case has mounting boards and hardware for 8 Raspberry Pis. You mount the Raspberry Pi onto the acrylic board, and then the mounting board easily snaps into the case. 

This is great for allowing you to start very small and expand as you would like. The price might seem like a considerable jump from the stackable case options but I still picked the Cloudlet Cluster Case because I think it looks nice, it's very sturdy, and had enough room for the network switch. 

You can also see a blue square in the image above - that's the Blinkstick Square with an enclosure. I plan to set up monitoring for the cluster, and for a variety of webhooks, and use the Blinkstick Square for showing status. I figured I would use white, red, green, blue, and purple to indicate which Pi/Node the status was for. 

 Raspberry Pis

Originally I was going to build a cluster from a couple old Raspberry Pis I have that I hadn't been using, but I bought a Raspberry Pi 4 bundle for my daughter and the performance is so good that I decided to get the newer Pis instead. 

I would have liked to have bought the Raspberry Pis from Amazon, because I appreciate the customer service you get from Amazon. However, I have had great luck with smaller businesses that sell Raspberry Pi products, and usually they have better prices than what you would good from Amazon. Canakit had Raspberry Pi 4B 8GB boards available before Amazon, and the price is about $15 cheaper. Vilros and the PiShop also had Raspberry Pi 4B 8GB boards listed, but had the same price as Canakit.

PoE Hats

I found a few PoE hat options, but I went for the official Raspberry Pi PoE hat

The price was better than most options, and I assumed there would be more testing around the official option. Also, one PoE hat that I looked at seemed to have a nicer profile but the seller suggests buying a fan for it. The official Raspberry Pi PoE hats come with fans attached and there is no issues with clearance in the Cloudlet Case. 

SD Cards

I bought 128 GB SD cards for each of the Pis. I didn't need SD cards that hold that much data because I can attach an external HDDs or SSDs to add storage. If I were to do this again, then I think I would buy smaller SD cards, and use the saved money to go towards external drives.

Network Switch

I bought an 8 port PoE switch from TPLink mainly because it was the cheaper option between it and a Netgear 8 port PoE switch. The TPLink switch is $30 cheaper than the Netgear equivalent. I had no problems at all - it works great with the Raspberry Pi PoE hats. There was no special configurations for the Raspberry Pi, no jumper settings for the PoE hat, and nothing to configure for the switch. Just connect all the things.

There will be a post coming soon that will list the steps I took to set up the Raspberry Pis and get K3s installed. It was relatively simple, but not completely hassle-free. The first time I was able to see that all nodes were running and available to the cluster made it worth it. 

Saturday, August 22, 2020

Welcome to 2020! Err...I mean, welcome to August 2020!

I love home projects where the main purpose is to learn something new. The only projects I love more are the next learning projects.

Here are some areas I want to learn more about:
  • Kubernetes
  • Tracking useful metrics
  • For the near future:
    • Serverless for Kubernetes
    • Load testing at a small scale
    • Data pipelines

Some of the items are very easy to explore at work but not all of them, so I plan to focus on projects that are not work specific.


You might ask, "Who isn't using Kubernetes?"

Well, I wasn't until recently!

It's been really fun. There are so many open-source projects that I want to use that will easily run on Kubernetes that it's almost hard to force myself to start at the beginning and learn how to set up and manage a cluster. Or even a tiny cluster - but that's what I'll do first!

I had wanted to make a Raspberry Pi cluster for a while and this provided the excuse. I bought some Raspberry Pis, a nice case, an unmanaged switch that had 8 PoE ports, PoE hats for the Raspberry Pis, SD cards, and network cables. I put the Pis in the case, installed k3s (Lightweight Kubernetes), and now I just need some projects to help provide areas to start digging!

I'll share the steps I followed, parts I used for putting the cluster together, and anything I might do differently if I were to start over in the near future.

Tracking Useful Metrics

One of my first plans for the cluster will be to add metric tracking. I'm not sure what metric tracking options there are, so I searched to find out what other people are using. I found a number of references to this cluster-monitoring repo, and it looks like the setup for k3s is very simple. I forked and cloned that repo, followed the quick start info for k3s (updated some configs), and Prometheus, AlertManager, and Grafana were soon available and showing some useful metrics!

I'll create a post about what I learn with monitoring in the near future. 


Following the Quickstart for K3s from the carlosedp/cluster-monitoring repo was very straightforward, and it would be my suggested monitoring choice to anyone setting up a Raspberry Pi based Kubernetes cluster. I might change my mind, but for now it seems like an easy and quick way to go.

For now I suggest forking the repo, and then push any changes you make to vars.jsonnet to your cluster-monitoring repo. That way you can add/remove monitoring for your cluster quickly using a script that clones your repo first.

Near Future Projects

There are a number of things that I want to explore at home:
  • Serverless options for Kubernetes (for example, OpenFaaS, KNative, and Kubeless)
  • Load testing at a small scale (for example, run load tests against a single service as part of a CI pipeline, or run a set of load tests against a smaller version of your production environment)
  • Explore a variety of data pipelines

Saturday, December 21, 2019

Taco Cat Goat Cheese Pizza - A great family game!

Taco Cat Goat Cheese Pizza!

Now say that 5 times really fast. It's hard to say. Now imagine having to say "Taco" "Cat" "Goat" "Cheese" "Pizza" in turn while laying down pictures of things that don't match the words. Then imagine having to slap your hand down on the card if the word you say matches the card. It's really difficult but fun!

Then add narwhals, groundhogs, and gorillas to the mix.

That's what you get with the game Taco Cat Goat Cheese Pizza

Fun and sore hands. And lots of laughter!
I bought this game a while ago but we only recently played it. It was surprising how much fun we had within the first round of playing it. We can hardly wait to play it again!

The suggested age is 8 years and up, but if you have a child that can read fairly well, then it is probably fine for younger ages. It was definitely no problem for our 7-year-old daughter. She did much better than I did!

Wednesday, June 26, 2019

Install Oh-my-zsh and powerline fonts on Ubuntu 18.04

I recently installed Ubuntu 18.04 on my X1 Carbon (1st Gen that sat under the bed for years), and I'm actually enjoying using this notebook again!

The first thing I did was install a few basics that included oh-my-zsh. I love the information that the prompt displays for your git repos. Shown below is oh-my-zsh using the agnoster theme. 

Oh-My-Zsh with Git Repo Status

However, if the powerline fonts aren't installed, then it doesn't look so great. The icons show up as boxes with X's in them. 

I didn't have the powerline fonts installed, so I searched for the correct way to install the fonts on Ubuntu and found that a bunch of people were having difficulties.

I ended up following the directions on the powerline font github repo's README, and it worked without too much effort, so I figured I would post all the steps I followed to get oh-my-zsh installed and configured the way I like it.

Oh-My-Zsh and Powerline Font Install

First, install oh-my-zsh.
sh -c "$(curl -fsSL"

After the install, you end up with a .zshrc file in your home directory. I updated the .zshrc file to use the agnoster theme instead of the default theme of robbyrussell. Just update the ZSH_THEME value.

Second, install the powerline fonts so you can see the nice status icons for the current directory of your git repos. You can install the fonts this way:
sudo apt-get install fonts-powerline

Or by cloning the git repo and running their install script:
git clone --depth=1
cd fonts
cd ..
rm -rf fonts

If after running those commands (which probably only needed to consist of the apt-get install), the prompt for zsh has not started showing the nice status icons and colorized branches, then you can update the fontconfig information by creating a file in this directory (create the directory if it doesn't exist):

Then copy this file to ~/.config/fontconfig/conf.d.

Followed by running the font config cache command, which will force the font config cache to be update (-f) and display status information (-v).
fc-cache -vf 

It was after I ran the fc-cache command that I noticed the terminal show the git repo status information with the branch and sattus icons. I used both the apt-get install fonts-powerline method, and the 

Sunday, January 27, 2019

Yeoman generator for creating a terraform directory structure for AWS providers...

I use AWS for work, and use terraform for creating the resources. My team uses a common directory structure for our terraform files, and it seems to work pretty well for separating resources between project groups, logical environments, and regions. However, creating new project directory structures can be a pain, so I decided to create a yeoman generator to automate the process. 

Please check out the generator I made, and let me know what you think!

Clone from git:
git clone

Install using npm:

npm install --global generator-tf-proj

Generate a terraform project structure using yeoman:

yo tf-proj

Saturday, January 20, 2018

AWS IoT Button and Philips Hue API...

I bought some Philips Hue Lights, and have really enjoyed them - but I enjoy them even more now that I have the IoT button integrated with the lights. 

Here is a video showing my AWS IoT button interacting with my Philips Hue Go lamp.

Philips Hue API:

The Philips Hue REST API is really easy to use to retrieve information about the lights connected to the Hue bridge, and for controlling the lights. You can follow the instructions on this page to help you get up and running with the API.

AWS IoT Button:

I had seen the AWS IoT button on Amazon and, although I didn't have any ideas of what I would do with the button, I wanted to work on a project which would use one of the buttons. I found this fun project that also uses an AWS IoT button, and the Philips Hue API with the Go lamp. I had bought a Philips Hue Go light, as well as a number of other Philips Hue lights, so I decided to recreate the project from the youtube video above but using an AWS lambda instead of using a raspberry pi

Something that was pointed out to me (embarrassingly) is that this method is not secure. Sending unencrypted information to the Hue bridge, which includes the auth, would allow an attacker to send their own API calls to the bridge. One of the API calls could have a security hole that could be used by an attacker / curious person. 

A couple of ideas I've had for using the Philips Hue lights are flash lights with certain colors to indicate either a rise above, or drop below, stock or crypto currency price points, and flash lights when people are close to home (integrate with IFTTT).

However, using the IoT button to control the lights looked fun and gave me an excuse to learn a little bit about AWS Lambdas. It's worth mentioning that Philips makes a switch that can be easily programmed to control your Philips Hue lights.

Parts list :

- Philips Hue Go light, but it works with all of the Philips Hue color lights
- AWS IoT Button

Set up IoT Button:

I used the "Getting Started" guide to set up the IoT button.  It walks you through registering your device, creating and activating a device certificate, creating and attaching an IoT policy to the device certificate, attach the certificate to a "Thing" (the button), and configuring your IoT button to know how to connect to your WiFi.

One of the last steps in the "Getting Started" guide is configuring and testing rules. The example has the IoT button pushes send an SNS message that gets sent as a text message to your phone. I decided to have the SNS message trigger a lambda, and use the lambda to send the REST calls to my Philips Hue bridge.

AWS Lambda:

Here is the AWS Lambda code that I used:

I have my router configured to use Dynamic DNS, and then I have a port forwarding rule to forward to the Philips Hue bridge.  The lambda figures out if the button click was a single click, a double click, or a long click.  The double clicks will turn the light on and off, the single click will increment the hue to set the light to, and a long click will set the light to use the color loop effect.

I hope you find this post useful! Please leave links to any projects you feel like sharing using AWS IoT buttons and/or Philips Hue lights in the comment section below.

Sunday, August 6, 2017

Create an AWS Lambda using Java...

Here's a quick walk through for creating an AWS lambda using Java. I happen to use IntelliJ with maven, but you can use whatever IDE and package management you prefer to use. You can find a similar walk-through in the online AWS documentation or in the AWS Lambda In Action book.

1. Create an IAM role for the Lambda to use:
  • Click the "Create new role" button.
  • In the "Select role type" section, Click the "Select" button for "AWS Lambda" from the "AWS Service Role" section.
  • Enter the policy name of "AmazonS3FullAccess", click the check box, and click the "Next step" button.
  • Enter a name in the "Role name" text box (for this example, use "hello-lambda-role"), and enter a fitting description in the "Role description" text box. Click the "Create role" button.

2. Create an S3 bucket.

3. Create a Java project for your AWS Lambda code:
  • Using IntelliJ, create a maven project using maven-archetype-quickstart.
  • Add the aws lambda core dependency to the project's pom file:

  • Create a class called HelloWorldLambda that implements RequestHandler<String, String>:

public class HelloWorldLambda implements RequestHandler<String, String> {
public String handleRequest(String input, Context context) {
    String output = "Hello, " + input + "!";
    return output;
  • Build the project so that the jar is created setting the output jar name to be HelloLambda.jar.

4. Create the lambda in the AWS console:
  • Click on the "Get Started Now" button.
  • Click on the "Blank Function" item.

  • On the "Configure triggers" page, click in the grey dashed square and then select "S3".
    • Select the bucket that you created in step 2.
    • Select the event type "Object Created (All)".
    • Click "Enable trigger".
  • Click the "Next" button. 
  • Enter a name for the lambda like "hello-lambda"
  • Select "Java 8" for the Runtime

  • Click on the "Upload" button and select your HelloLambda.jar.

  • In the "Lambda function handler and role", enter the full package path to your HelloWorldLambda class.
  • Select "Choose an existing role" for the Role section.
  • Select the "hello-lambda-role" that you created in step 1.

  • In the "Tags" section, enter the value "Name" for the key, and "hello-lambda" for the value.

  • In the "Advanced settings", increase the memory to 512 MB. Leave the timeout at 15 seconds.

  • Click the "Create function" button.

5. Test the lambda!

* Go to "Functions" section of the AWS console's Lambda page.
* Select the "hello-lambda" function by clicking the option button.
* Click on the "Actions" drop down, and click on "Test function". The "Input test event" dialg will appear.
* Enter the text "testing", and then click the "Save and test" button.

This will trigger the lambda function, and you'll see the output in the "Execution result" section.

6. Test the lambda with an S3 creation event:

Uploading a text file with a single line of text to your S3 bucket that you created in step 2 will trigger your lambda, and you can see that the lambda is invoked by using the following steps.

  • Go to the AWS Lambda console page, and select the "Functions" section.
  • Click on the "hello-lambda" function. This should take you to the details for your lambda.  
  • Click on the "Monitoring" tab. 

You'll see that you have invocations for both the test run, and the S3 upload. My image shows invocations for multiple file uploads, and multiple tests.

Learn more about AWS Lambdas through AWS Lambda In Action.