Setup Ubuntu on Raspberry Pi

Download latest LTS image from official site.

Ubuntu - Install Ubuntu on a Raspberry Pi

Write the image to your SD-card. In this example, SD-card is mounted on /dev/sdc.

xzcat ubuntu-20.04.3-preinstalled-server-arm64+raspi.img.xz | sudo dd of=/dev/sdc bs=1M

Mount SD-card on your Mac.
```
cd /Volumes/system-boot
```
Enable SSH.
```
touch ssh
```

Optional: Disable bluetooth if don't need.

echo "dtoverlay=disable-bt" >> config.txt

Optional: Disable WiFi if don't need.

echo "dtoverlay=disable-wifi" >> config.txt

Optional: Activate cgroup if use docker and kubernetes.

vi /Volumes/system-boot/cmdline.txt
<snip> cgroup_enable=cpuset cgroup_enable=memory cgroup_memory=1