16% of all hosting nodes (a category that makes up 62% of all nodes by network type) are hosted with Hetzner — 10% of all nodes. If 10% of all Ethereum nodes being supported by one company sounds awfully centralized to you, wait til you hear that 30% run on Amazon services.
10% of Ethereum nodes at risk of being booted from cloud hosting provider
The virtual server provider Hetzner posted a clarification that using its service to mine Ethereum — either in its current form or in the promised proof-of-stake version — violates its terms of service and that the company has been "internally discussing how we can best address this issue".