Raspberry Pi Cluster — Setup & Verification Guide

Infrastructure: 1× Pi5 (master, 192.168.1.50) + 8× Pi3 (workers, 64-bit, diskless PXE boot)

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1. WiFi Setup

Connect any node to WiFi

# SSH into node
ssh pi@192.168.1.58

# Unblock WiFi and scan
sudo rfkill unblock all
sudo ip link set wlan0 up
sudo nmcli device set wlan0 managed yes
sudo nmcli device wifi rescan
sleep 3
sudo nmcli device wifi list

# Connect
sudo nmcli device wifi connect "YOUR_SSID" password "YOUR_PASSWORD"

# Verify
ip addr show wlan0
ping -c 3 8.8.8.8

Connect Pi5 to WiFi

# On Pi5 directly
sudo nmcli device wifi rescan
sleep 3
sudo nmcli device wifi list
sudo nmcli device wifi connect "YOUR_SSID" password "YOUR_PASSWORD"
ping -c 3 8.8.8.8

3. Verify 64-bit OS on All Nodes

for IP in 192.168.1.58 192.168.1.54 192.168.1.104 192.168.1.136 \
          192.168.1.86 192.168.1.117 192.168.1.83 192.168.1.133; do
  RESULT=$(ssh -o ConnectTimeout=3 -o StrictHostKeyChecking=no pi@$IP \
    "uname -m && uname -r" 2>/dev/null)
  echo "$IP: $RESULT"
done

Expected output:

192.168.1.58:  aarch64    ← 64-bit ✅
               6.12.x+rpt-rpi-v8
192.168.1.54:  aarch64    ✅
...

aarch64 = 64-bit ARM. If you see armv7l = still 32-bit.

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4. Shared Filesystem Read/Write Test

Test root is writable (shared)

# Write from one node
ssh pi@192.168.1.58 "echo 'hello from worker1' | sudo tee /shared-test.txt"

# Read from different nodes — should all see same file
for IP in 192.168.1.54 192.168.1.104 192.168.1.136 \
          192.168.1.86 192.168.1.117 192.168.1.83 192.168.1.133; do
  RESULT=$(ssh -o ConnectTimeout=3 -o StrictHostKeyChecking=no pi@$IP \
    "cat /shared-test.txt" 2>/dev/null)
  echo "$IP: $RESULT"
done

# Cleanup
sudo rm /nfs/rootfs64/shared-test.txt

Test per-node /etc is writable (isolated)

# Each node should write to its OWN /etc only
for IP in 192.168.1.58 192.168.1.54 192.168.1.104 192.168.1.136 \
          192.168.1.86 192.168.1.117 192.168.1.83 192.168.1.133; do
  RESULT=$(ssh -o ConnectTimeout=3 -o StrictHostKeyChecking=no pi@$IP \
    "sudo touch /etc/test-write && echo 'etc: WRITABLE ✅' && sudo rm /etc/test-write" 2>/dev/null)
  echo "$IP: $RESULT"
done

Verify mount layout on any node

ssh pi@192.168.1.58 "mount | grep nfs"

Expected:

192.168.1.50:/nfs/rootfs64          on /      (rw)  ← shared root
192.168.1.50:/nfs/nodes/<serial>/etc on /etc  (rw)  ← per-node
192.168.1.50:/nfs/nodes/<serial>/var on /var  (rw)  ← per-node
192.168.1.50:/nfs/nodes/<serial>/home on /home (rw) ← per-node

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5. Time Sync Verification

Check Pi5 is synced to internet

chronyc tracking
chronyc sources -v
timedatectl status

Expected:

System clock synchronized: yes
NTP service: active
Reference ID: x.x.x.x (pool.ntp.org server)

Check all nodes sync from Pi5

for IP in 192.168.1.58 192.168.1.54 192.168.1.104 192.168.1.136 \
          192.168.1.86 192.168.1.117 192.168.1.83 192.168.1.133; do
  RESULT=$(ssh -o ConnectTimeout=3 -o StrictHostKeyChecking=no pi@$IP \
    "chronyc tracking | grep 'Reference ID' && date" 2>/dev/null)
  echo "=== $IP ==="; echo "$RESULT"
done

Expected:

=== 192.168.1.58 ===
Reference ID: C0A80132 (192.168.1.50)  ← syncing from Pi5 ✅
Sat 30 May 2026 ...                    ← correct date ✅

Force immediate time sync on all nodes

for IP in 192.168.1.58 192.168.1.54 192.168.1.104 192.168.1.136 \
          192.168.1.86 192.168.1.117 192.168.1.83 192.168.1.133; do
  ssh -o ConnectTimeout=3 -o StrictHostKeyChecking=no pi@$IP \
    "sudo chronyc makestep && date" 2>/dev/null
  echo "$IP synced"
done

Check Pi5 sees all nodes as NTP clients

chronyc clients

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6. Install Library Once — Available on All Nodes

Method — chroot into shared rootfs on Pi5

# One command to enter chroot
chroot-rootfs enter

# Inside chroot — install anything
apt update
apt install -y htop python3 vim git wget curl

# Exit chroot (auto-unmounts)
exit

Or install without entering chroot:

chroot-rootfs install htop python3 vim git

Verify package available on ALL nodes immediately

for IP in 192.168.1.58 192.168.1.54 192.168.1.104 192.168.1.136 \
          192.168.1.86 192.168.1.117 192.168.1.83 192.168.1.133; do
  RESULT=$(ssh -o ConnectTimeout=3 -o StrictHostKeyChecking=no pi@$IP \
    "which htop && htop --version" 2>/dev/null)
  echo "$IP: $RESULT"
done

If package has /etc config — copy to all nodes

# Example: after installing a package that puts config in /etc
for SERIAL in a7b7e022 2c900aeb 2f14a0f1 33cc973b 5ee65e7e c4ff9387 f2893559 c782ffc3; do
  sudo cp -r /nfs/rootfs64/etc/PACKAGE_NAME /nfs/nodes/$SERIAL/etc/
done

Why this works

chroot writes to /nfs/rootfs64/usr/bin/htop
All nodes mount /nfs/rootfs64 as /
Therefore all nodes see /usr/bin/htop instantly
No need to touch individual nodes!

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7. Cluster Health Check (All-in-One)

Run this to verify everything at once:

echo "========================================="
echo "CLUSTER HEALTH CHECK"
echo "========================================="

echo ""
echo "--- Pi5 Time Sync ---"
timedatectl status | grep "synchronized\|NTP"

echo ""
echo "--- Pi5 NFS Exports ---"
sudo exportfs -v | grep -E "rootfs64|nodes"

echo ""
echo "--- Node Status ---"
for IP in 192.168.1.58 192.168.1.54 192.168.1.104 192.168.1.136 \
          192.168.1.86 192.168.1.117 192.168.1.83 192.168.1.133; do
  RESULT=$(ssh -o ConnectTimeout=3 -o StrictHostKeyChecking=no pi@$IP \
    "echo \$(hostname):\$(uname -m):\$(date '+%Y-%m-%d %H:%M')" 2>/dev/null)
  if [ -n "$RESULT" ]; then
    echo "$IP: $RESULT ✅"
  else
    echo "$IP: ❌ NOT REACHABLE"
  fi
done

echo ""
echo "--- NFS Mounts Active ---"
sudo showmount -a | grep -v "^All"

echo "========================================="

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8. Node Reference Table

Node	IP	MAC	Serial
pi5-master	192.168.1.50	88:a2:9e:b1:76:54	—
worker1	192.168.1.58	b8:27:eb:b7:e0:22	a7b7e022
worker2	192.168.1.54	b8:27:eb:90:0a:eb	2c900aeb
worker3	192.168.1.104	b8:27:eb:14:a0:f1	2f14a0f1
worker4	192.168.1.136	b8:27:eb:cc:97:3b	33cc973b
worker5	192.168.1.86	b8:27:eb:e6:5e:7e	5ee65e7e
worker6	192.168.1.117	b8:27:eb:ff:93:87	c4ff9387
worker7	192.168.1.83	b8:27:eb:89:35:59	f2893559
worker8	192.168.1.133	b8:27:eb:82:ff:c3	c782ffc3

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9. Directory Structure on Pi5

/nfs/
├── rootfs64/          ← Shared 64-bit OS root (all nodes, rw)
├── boot64/            ← PXE boot files
│   ├── bootcode.bin   ← First stage bootloader
│   ├── kernel8.img    ← 64-bit kernel
│   ├── cmdline.txt    ← Default boot params
│   ├── a7b7e022/      ← Per-node boot (worker1)
│   │   └── cmdline.txt
│   ├── 2c900aeb/      ← Per-node boot (worker2)
│   └── ...
└── nodes/
    ├── a7b7e022/      ← worker1 private data
    │   ├── etc/       ← worker1's /etc
    │   ├── var/       ← worker1's /var
    │   └── home/      ← worker1's /home
    ├── 2c900aeb/      ← worker2 private data
    └── ...

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10. Useful Commands Reference

# SSH into a node
ssh pi@192.168.1.58

# Run command on ALL nodes
for IP in 192.168.1.58 192.168.1.54 192.168.1.104 192.168.1.136 \
          192.168.1.86 192.168.1.117 192.168.1.83 192.168.1.133; do
  ssh -o ConnectTimeout=3 -o StrictHostKeyChecking=no pi@$IP "YOUR_COMMAND"
done

# Reboot all nodes
for IP in 192.168.1.58 192.168.1.54 192.168.1.104 192.168.1.136 \
          192.168.1.86 192.168.1.117 192.168.1.83 192.168.1.133; do
  ssh -o ConnectTimeout=3 -o StrictHostKeyChecking=no pi@$IP "sudo reboot" &
done

# Install package for all nodes (chroot on Pi5)
chroot-rootfs install PACKAGE_NAME

# Check all nodes are up
for IP in 192.168.1.58 192.168.1.54 192.168.1.104 192.168.1.136 \
          192.168.1.86 192.168.1.117 192.168.1.83 192.168.1.133; do
  ping -c 1 -W 2 $IP &>/dev/null && echo "$IP ✅ UP" || echo "$IP ❌ DOWN"
done

# Check NFS server status
sudo exportfs -v
sudo showmount -a

# Restart all services on Pi5
sudo systemctl restart nfs-kernel-server dnsmasq chrony

# Remove file from shared rootfs
sudo rm /nfs/rootfs64/PATH/TO/FILE

# Remove folder from all nodes
for SERIAL in a7b7e022 2c900aeb 2f14a0f1 33cc973b 5ee65e7e c4ff9387 f2893559 c782ffc3; do
  sudo rm -rf /nfs/nodes/$SERIAL/PATH/TO/FOLDER
done