And with hetzner you can rent bare metal servers as well. It is somewhat equivalent to renting rack space, but they bring the servers, not you. The advantage is that if a server fails, they can provision a new one in less than 1 hour. The disadvantage is that you are probably running on somewhat refurbished hardware that has a higher prob of failing (at least these were the rumors in the past). 5-6 years ago, this was (by far) the most cost effective solution for Hadoop/HDFS deployments. IDK what the status quo is now.

As others have pointed out it is relatively easy to deploy small k3s clusters on Hetzner Cloud.