Platform Request: Hetzner

[aral]

In order to implement support for a new cloud platform in Fedora CoreOS, we need to know several things about the platform. Please try to answer as many questions as you can.

Hetzner: https://www.hetzner.com/cloud

• Why is the platform important? Who uses it?

“Hetzner Online GmbH is a company and data center operator based in Gunzenhausen, Germany.” – https://en.wikipedia.org/wiki/Hetzner

According to Enlyft, over 180,000 companies use their services.

In 2021, they apparently had over 200,000 servers in just one of their data centres (https://www.youtube.com/watch?v=5eo8nz_niiM).

Personally, they offer the fastest instance creation times I’ve seen, an excellent API, and their prices are among the lowest available. All of these make them perfect for use for the small web. Unfortunately, since they don’t support CoreOS, I’m going to likely have to build the small web stuff on Ubuntu to start with. Which is less than ideal as I’d love for the instances to be auto-updating with a minimum of maintenance required. (The closest thing to that currently is Ubuntu LTS with automatic security updates enabled but that doesn’t, of course, cover major version updates.)

• What is the official name of the platform? Is there a short name that's commonly used in client API implementations?

Hetzner.

• How can the OS retrieve instance userdata? What happens if no userdata is provided?

Currently uses CloudInit, as far as I know (at least for Ubuntu instances). If no userdata is provided, no customisation occurs.

• Does the platform provide a way to configure SSH keys for the instance? How can the OS retrieve them? What happens if none are provided?

Yes (through their interface/API). If none are provided, it sets a root password and emails it to the person.

• How can the OS retrieve network configuration? Is DHCP sufficient, or is there some other network-accessible metadata service?

I don’t know, sorry.

• In particular, how can the OS retrieve the system hostname?

All regular hostname commands appear to work. Not sure if that’s what you’re asking though.

• Does the platform require the OS to have a specific console configuration?

I don’t know, sorry.

• Is there a mechanism for the OS to report to the platform that it has successfully booted? Is the mechanism required?

Not sure.

• Does the platform have an agent that runs inside the instance? Is it required? What does it do? What language is it implemented in, and where is the source code repository?

I don’t believe so. I haven’t encountered it in the instances I’ve set up, at least.

• How are VM images uploaded to the platform and published to other users? Is there an API? What disk image format is expected?

Online interface + API. I haven’t used this personally.

• Are there any other platform quirks we should know about?

Likely, but I haven’t encountered any in my use of their services :)

[bgilbert]

Thanks for filing this. Note that we'll need these answers from the OS perspective, not the user perspective. E.g., how does the OS fetch userdata? How does it learn its own hostname?

[bgilbert]

Some previous discussion in:

• providers: add initial hetzner cloud support ignition#667
• 🇩🇪 Add support for Hetzner cloud ignition#1262
• providers: add support for hetzner cloud afterburn#125
• coreos-base/oem-hcloud: add hetzner cloud support coreos-overlay#3490 (comment)

Apparently the platform is sometimes called hcloud.

[jlebon]

We discussed this in today's community meeting:

13:10:54 < jlebon> #agreed we would like to add support for Hetzner. we are looking
                   for volunteers to pick it up and push it forward.

[aral]

Happy to hear it. Would you like me to ask around to see if I can find some contacts there or do you already have folks you can talk to?

[bgilbert]

Yes, that would be helpful, thanks!

[aral]

Quick update: I’ve been in touch with an engineer at Hetzner:

“I passed it to the responsible people but they are on vacation for the next two weeks … I will force it to be answered then :)”

[der-On]

At least for reseting passwords a "QEMU Guest Agent" is running on the OS.

[bgilbert]

@der-On That might be the standard QEMU one, discussed in #74. We generally avoid shipping third-party agents (and reimplement pieces of them when necessary to avoid it), and don't currently ship the QEMU one.

[asciiprod]

So, how could we help to get CoreOS running on Hetzner Cloud?