Raspberry Pi

To run K3s on a Raspberry Pi, we need to ensure that the system is properly configured. Below are the steps to prepare Raspberry Pi for K3s installation.

On the Raspberry Pi modify /boot/firmware/cmdline.txt to include cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory

nano /boot/firmware/cmdline.txt

Paste in cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory (make sure it is all on one line)

After a rebot verify with

# Show the *effective* kernel cmdline after boot
cat /proc/cmdline

edit /etc/dphys-swapfile and set CONF_SWAPSIZE=0

nano /etc/dphys-swapfile

then run the following commands to disable and reconfigure swap

apt update
apt install dphys-swapfile -y
apt remove systemd-zram-generator -y
dphys-swapfile swapoff
dphys-swapfile setup

Static IP address

A static IP address is recommended for the Raspberry Pi to ensure consistent connectivity.

nano /etc/hosts

and change 127.0.0.1 to desired static IP address

This should return the static IP address

hostname --ip-address

Next use nmcli to set a static IP address.

nmcli connection add type ethernet ifname eth0 con-name static-eth0 ipv4.addresses 192.168.1.11/24 ipv4.gateway 192.168.1.1 ipv4.dns 192.168.1.60 ipv4.method manual
nmcli connection up static-eth0

use ip a to verify the static IP address is set correctly

Fans

Set the fans to only turn on when the CPU temperature exceeds 60 degrees Celsius.

sudo nano /boot/firmware/config.txt

Add this line to the end of the file:

# Enable cooling fan control
dtoverlay=gpio-fan,gpiopin=14,temp=70000

We can check the temperature of the CPU with the following command:

watch -n 1 vcgencmd measure_temp

We can check the fan speed using cat /sys/class/thermal/cooling_device0/cur_state which will be a value between 0 and 255. Or checking GPIO 14 using pinctrl get 14 where hi means the fan is on (100% speed) and lo means the fan is off (0% speed).