Today I was in a situation where I need to have disk quotas enabled on a Hetzner VPS. They are not enabled by default. These are the commands I used to enable disk quotas on Hetzner.

You need to execute these commands as the root user. Also make sure a take a snapshot before proceeding.

Install quota packages,

apt install quota quotatool

Install Linux generic Package,

apt install linux-generic

Start quota modules at system reboot,

echo quota_v1 >> /etc/modules

echo quota_v2 >> /etc/modules

Reboot system,

reboot

That's it. Disk quotas should be working when the server comes back up online.