Walk-through — install Kubernetes to your Raspberry Pi in 15 minutes

Here’s something you can do before work, with your morning coffee, or whilst waiting for dinner to cook of an evening. And there’s never been a better time to install Kubernetes to a Raspberry Pi, with the price-drop on the 2GB model — perfect for containers.

You can buy a single RPi and still have a lot of fun, here I bought 4x 2GB nodes

I’ll show you how to install Kubernetes to your Raspberry Pi in 15 minutes including monitoring and how to deploy containers.

Updates:

  • Dec 2020 — added instructions for cgroups and
  • Jan 2021 — added multi-arch command instead of to use new templates and Docker buildx
  • Mar 2021 — Raspbian is now Raspberry Pi OS

The bill of materials

I’ll keep this quite simple.

  • Raspberry Pi 4, with 2GB or 4GB RAM — the 2GB is the best value, 4GB is best if you don’t plan on doing clustering.
  • SD card — 32GB recommended, larger is up to you, but Kubernetes writes to disk a lot and could kill a card, so I tend to prefer buying more smaller cards.
  • Power supply — you need the official supply, I know it’s expensive, but that’s for a reason. Don’t be cheap because you’ll buy twice.
  • Docker Desktop — if you want to build your own images, you need to cross-compile them from a PC with buildx, do not install docker on your nodes.

If you’d like some links, you can find them in my home-lab post: Kubernetes Homelab with Raspberry Pi and k3sup.

Flash the initial OS

There are so many ways to install an Operating System, but I recommend Raspberry Pi OS and the Lite edition which ships without a UI.

Once you download the image, you can use Etcher.io from our friends at Balena to flash it without even unzipping it. How cool is that?

Before you boot up that RPi, make sure you create a file named in the boot partition. If on a Mac you'll see that gets mounted for you as soon as you eject and re-insert the SD card.

Connect for the first boot

Now connect to the Raspberry Pi over your local network, it will show up as , but if you can’t connect for some reason, then install and run to run a network scan.

  • Change the password with .
  • Run and change the memory split to , so that we have all the RAM for Kubernetes, believe me, it needs it.

There’s one more change that’s essential for k3s. Add the following to , but make sure that you don’t add new lines.

Copy or create an SSH key

k3sup uses password-less login by default, so that means you can run it from a script or automation without human intervention.

Copy your SSH key to the Raspberry Pi with:

If you have no SSH key on your local computer yet, then run

Get your CLI tools

You do not need to log into your Raspberry Pi again. All tools will be installed on your client (i.e. your laptop) and the RPi will be accessed remotely as a server.

  • arkade — a hassle-free way to get Kubernetes apps and CLIs
  • kubectl — the Kubernetes CLI
  • k3sup — the Kubernetes (k3s) installer that uses SSH to bootstrap Kubernetes

arkade is a portable Kubernetes marketplace which makes it easy to install around 40 apps to your cluster, without worrying about all the gory details and configuration options. arkade also “does the right thing” for instance:

  • An app like OpenFaaS uses a helm chart
  • A tool like the Kubernetes dashboard only uses plain YAML manifests
  • Linkerd for example prefers to use a CLI

arkade abstracts that all away from the user with around 40 apps on offer. On top of that, if an app like Istio is known not to work on your device, it will block you from doing the wrong thing.

We can also use it to download and :

Did you know that you can also specify a version to ? For example:

can be used to install k3s as a server, to begin a new single-node cluster (that’s what we’ll do today). If you have multiple nodes, then the command lets you add in additional agents or workers to expand the capacity.

Install Kubernetes with k3sup and k3s

k3s is a lightweight edition of Kubernetes made by Rancher Labs, it’s suitable for production, but also perfect for small devices like our Raspberry Pi. Its memory requirements are around 500MB for a server vs. around 2GB for kubeadm (upstream Kubernetes)

In a few moments you’ll receive a kubeconfig file into your local directory, with an instruction on how to use it.

Find the node, and check if it’s ready yet

You can add to most kubectl commands to “watch” or “stream” the output status, so you can save on typing.

By default k3s comes with the metrics-server, which is used for Pod autoscaling and getting memory/CPU for pods and nodes:

Now let’s install one or two apps, run to see what's available, but not that not all projects in the CNCF landscape work on ARM devices.

Let’s try the Kubernetes dashboard?

The installation script prints out how to use the app, and can show us the same information later too.

Paste in your token

Now enjoy the dashboard:

Let’s install another popular application, openfaas. OpenFaaS gives us a simple way to deploy functions and microservices to Kubernetes with built-in auto-scaling.

Log in using the post-installation information.

The IP of my RPi is 192.168.0.201, so I can access OpenFaaS using a NodePort of 31112.

Now open the OpenFaaS UI and check your figlet function using or the equivalent.

You can also build your own functions with Python, Go, JavaScript and many other languages.

If you have a Docker Hub login, then you can try the following, but you’ll need to run it on a separate Raspberry Pi, with installed ()

Doing multi-arch right

If you’re running 64-bit Ubuntu on your Raspberry Pi, then you’ll need to use instead. You can also build for multiple platforms by adding them with a comma between each. Just run to find out an example of how.

You can also edit the function’s code and then run then again:

Contents of:

Find out more about OpenFaaS at openfaas.com

You can also see your functions on the Kubernetes Dashboard:

Get a public IP for your cluster

You can get a public IP for your cluster via a tunnel using the popular Open Source project inlets.

Self-host websites and APIs

Build your own homelab cluster for self-hosting

If you’d like to build a resilient homelab, that has multiple master nodes (servers) and uses faster, more reliable network storage, checkout my new workshop available on Gumroad.

In the workshop, you’ll learn how to configure a netbooting server, then boot your Raspberry Pi directly from the network, from there you can install K3s and explore different applications you can add on top. High Availability is essential for self-hosting, so that your cluster can tolerate a host failure.

Wrapping up and next steps

If you want to take things further, you can start adding additional nodes into the cluster, to extend its capacity and to give redundancy.

You can connect with the OpenFaaS community — to talk about Kubernetes, ARM, Raspberry Pi clusters and serverless. Join our Slack workspace today.

CNCF Ambassador. OpenFaaS & Inlets founder — https://www.alexellis.io

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