5 reasons to build a mini Kubernetes cluster with your Raspberry Pi

Kubernetes has been an industry buzzword for a decade, leading a container orchestration revolution in how we run and deploy applications on bare metal and in the cloud. But is Kubernetes overkill for your home lab? Yes, but that’s never stopped us from delving into other excesses like ex-enterprise networking gear.

Building a mini Kubernetes cluster is an excellent project for your lab and one with profound potential benefits, depending on your setup. This project isn’t for everyone, but it offers tremendous learning potential. So here are some of the reasons why building a Raspberry Pi Kubernetes cluster is an excellent addition to your home lab.

5 Kubernetes is great for learning

Learn fast and break things

Source: Unsplash

Kubernetes is a potent tool that’s swept through the whole tech industry over the last decade. It’s a flexible container orchestration tool that allows you to build everything from massive clusters of self-healing, auto-deploying applications to simple clusters using single-board computers like the Raspberry Pi to run some apps at home. Yes, it’s likely complete overkill for most things you’re running at home, but running your own applications on Kubernetes is a significant learning opportunity.

Whether you’re using Helm or Kubectl to deploy your applications directly, messing with other tools like Argo CD, or just using TrueNAS to deploy some media apps on your NAS, the opportunities for learning with Kubernetes are huge. There’s a massive community and plenty of helpful learning resources online for everyone, from complete beginners to seasoned sysadmins. Kubernetes can expand your understanding of everything from basic networking to the cloud, and it is especially ideal to know about it if you’re a developer or working in the tech sphere.

If you’re using Kubernetes at home, we caution you against storing critical data there. Understanding the managing of persistent volumes and stateful applications can be difficult in an ephemeral environment. There’s nothing inherently wrong with this, but it can be trickier to get right, and we’d suggest you gain some experience with Kubernetes first.

4 Raspberry Pis are perfect for a cluster

Single-board computers like the Raspberry Pi are perfect for a home Kubernetes cluster, allowing you to build a decent-sized multi-node cluster with a decent amount of memory and CPU performance on each board. There are other benefits, too. The gigabit internet on recent Pis will be essential for optimal cluster performance (especially if you’re using some distributed storage), and its compact size makes it easy to stow away in a corner or cupboard with a small network switch.

There’s an entire ecosystem of people building around the Pi, and plenty of accessories like cluster cases are available, either to buy your own or 3D print. The low energy usage, small form factor, and perfect feature set, make the Pi an ideal choice for a home cluster. You can use K3s, a smaller, more lightweight Kubernetes distribution, to get started easily on your Pi, and there are plenty of useful tutorials and guides online.

3 Kubernetes is great for your home lab

An overkill but powerful platform to run your apps

If you’re a homelabber like me, having a Kubernetes platform not only to learn on but to get some applications deployed is a handy addition to your lab. Whether you’re hosting some internal tools, a VPN, or using scheduled jobs or other elements of Kubernetes to schedule and run complex container workloads, you won’t find Kubernetes to be the limiting factor. If you’re looking for a more “modern” lab, K8s is also perfect here, leaving the days of manually installing your SSH keys on each box or running commands using orchestration tools like Ansible behind.

Another nice benefit of using Kubernetes is the ability to leverage management tools like Helm, which makes installing applications as easy as a single command on your cluster. This gives you the option of skipping all the nuts and bolts and simply installing a pre-configured application with some sensible defaults, though depending on the app, you might need to do some tweaking.

This makes Kubernetes a great platform to build on top of for your lab, one that you’re extremely unlikely ever to outgrow.

2 Monitoring is easy

Just keep it simple

One thing I see constantly being overlooked in most people’s home labs is the integration of any monitoring, either for system or application metrics or even basic data from your nodes. Kubernetes makes this easy(ish), with the kube-prometheus-operator and other monitoring stacks integrating easily. Kubernetes was designed with monitoring in mind from the ground up, and it’s relatively easy to drop in a monitoring setup built by the community to keep tabs on your cluster — just be careful not to overload the available resources.

The world is your oyster here. You could use your cluster as a monitoring instance for your whole network or lab or deploy another stack elsewhere. You can set up alerts with tools like Alert Manager to warn you if things are going wrong, including by sending notifications with apps like Slack, PagerDuty, or even SMS alerts. If you’ve got something like a pfSense router, you can even monitor that using the tools you set up in Kubernetes.

1 Scaling your cluster is easy

Something I really like about using a Raspberry Pi cluster is that it’s easy to scale and shrink your cluster as your needs change. Initially, I’d suggest starting with a two or three-node cluster, but once you’ve set up K3s once or twice on a Raspberry Pi, it’s a pretty simple process. Part of the beauty of Kubernetes (mostly, not always) is that it’s easy to grow your cluster as you need, with Kubernetes easily migrating your containers/pods to a new node.

If you need to reclaim a Raspberry Pi for another project, it’s not too difficult to remove a node, especially if you’re not using a lot of stateful applications.

Related

8 home lab disasters that can end up costing you hundreds of dollars

Home lab nightmares that will drain your wallet

A multi-node cluster is an excellent addition to your lab

Whether you’re just using it to expand your skills, for the development of apps or other tools, or using it to run internal tools and services, a Raspberry Pi cluster is a great addition to your home lab. Kubernetes isn’t for everyone, and diving in without prior knowledge requires a commitment to learning. However, the payoff is enormous.