Raspberry PI: install ClusterHAT software

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Published: Jan 29, 2024 (updated)

I’ve had these nice Raspberry Pi Zero (vanilla, not ‘W’) lying around for quite some time and I wanted to give them a purpose in life.

By chance (meaning, during my endless browsing of the Twitter-verse and the Reddit-verse) I have discovered the ClusterHAT (Hardware Attached on Top) which “interfaces a (Controller) Raspberry Pi A+/B+/2/3 with 4 Raspberry Pi Zeros configured to use USB Gadget mode”. To discover more: https://clusterhat.com/.

After installing, breaking, fixing, re-installing multiple times I’ve found myself with a nice-and-cheap Docker Swarm cluster, and a bit of knowledge on Raspberry Pi + ClusterHAT + Docker that I’m happy to share.

This is the (short) story of how I’ve put them all to work together.

On any available computers, write the images onto the SDs. For instance, on a *nix machine:

Before starting, clean up the SD card by removing any existing partitions.

• <type> = CBRIDGE, CNAT, pN
• <device> = e.g /dev/sdb, /dev/mmcblk0…

NOTE: based on “Buster” hence “2019-04-08”

$ sudo dd if=2023-05-03-4-buster-ClusterCTRL-armhf-lite-<type>.img of=/dev/<device> status=progress bs=1M

Before unmounting the SDs, do the following…

Enable SSH

$ touch /media/<your-username>/boot/ssh

Setup static address [CBRIDGE|CNAT|Zero]

$ sudo vi /media/<your-username>/rootfs/etc/dhcpcd.conf
interface [br0|eth0|usb0]
static ip_address=<ip_address>/24
static routers=<gateway>
static domain_name_servers=<gateway> <server1> <server2>

Either manually or through raspi-config (recommended)

Edit: password, hostname, timezone, SSH

Additional steps on Controller (optional)

$ ssh-keygen -t rsa

$ for idx in {1..4}; do ssh-copy-id pi@p${idx}.local; done

Also, to set vi as the default editor:

$ echo 3 | sudo update-alternatives --config editor

Using ClusterHAT

$ clusterhat status
clusterhat:1
clusterctrl:False
maxpi:4
...
p1:0
p2:0
p3:0
p4:0

$ clusterhat on

$ clusterhat status
clusterhat:1
clusterctrl:False
maxpi:4
...
p1:1
p2:1
p3:1
p4:1

Serial connection (useful to troubleshoot SSH issues)

$ minicom p[N]
 p[N] login: pi
 Password:
 Last login: Tue Sep 24 15:37:25 CEST 2019 from xxx.xxx.xxx.xxx on pts/0
 Linux p[N] 4.19.66+ #1253 Thu Aug 15 11:37:30 BST 2019 armv6l
...

NOTE: to quit Minicom use CTRL-A-X

clusterctrl: all commands