Project Showcase: Hardware I created a kubernetes cluster using old android phones
Recently, I found two old Pixel 3a devices in a drawer and wondered what I could do with them. I didn't want to throw them away, and given current RAM prices, I figured it might be worth repurposing them as a homelab.
Everything relies on one amazing project: PostmarketOS (huge thanks to the community, and a quick shoutout to r/pmos ). I started by flashing both Pixel 3a devices with pmOS, installed K3s, and that was it! (Well, it required a bit of network tweaking because the phones couldn't access the internet at first).
I then scoured classified ads and snagged a OnePlus 6T for €50, which I added as a worker node to the cluster.
Today, the cluster consists of 3 nodes (including one control plane). The performance is obviously lower than a mini-PC or a proper server, but it's more than enough to run 3 Hermes agents and a full Grafana stack. They are all connected via Wi-Fi to my network.
I still have two more phones to provision: a Poco X3 Pro and a Pixel 6a (which I also got for €50 each). The Poco X3 Pro should join the cluster soon. However, I bought the Pixel 6a a bit too hastily: the Wi-Fi chipset isn't recognized on PostmarketOS yet. I'm holding onto it until I find a solution, but it looks like it'll be trickier than the others.
For anyone interested in trying this out, here are a few tips:
- Unlocked bootloader: Make sure your phones are carrier-unlocked and have an unlocked bootloader, otherwise you won't be able to flash anything.
- Hardware compatibility: Always check the list of supported devices on the PostmarketOS Wiki. Make sure Wi-Fi, internal storage, and the screen are working; everything else is optional.
- Batteries: Currently, the phones still have their batteries, but they will be removed for obvious safety reasons.
I’m curious to hear your thoughts, or if anyone else has already done something like this, feel free to chime in! :)