hardware-hetzner-online: automatically discover the IPv6

[zimbatm]

This is a research ticket.

We currently provide the IPv6 manually to each server because they are not advertised via RA. Let's find a way to discover it automatically.

Things to check:

• DHCPv6
• Hetzner Support
• IPXE
• Other distros like Talos

[zimbatm]

IPXE

Here are some infos from the rescue system:

$ curl http://188.40.24.200/api/v2/tftp/boot_config
#!ipxe
set default-server http://fsn1-dhcp1.hetzner.company/tftp
set default-nfs 213.133.99.101:/nfs
set rescue_hash $6$7qya5Tk9V8.ByWQR$vPbm45rAvMXd9QKscqc8wbJbW31DX2XvvQInIk7LN6fXxI6BVAAIj5xLdaC0FgaoObtWbufsEyoxsIqi5FiBN0
set keyboard de
chain ${default-server}/ipxe/menu.ipxe

$ cat /proc/cmdline
vmlinuz initrd=initrd.img nfsdir=[2a01:4ff:ff00::b007:1]:/nfs RFILE=rescue-amd64-bookworm-v010.ext2 HASH=<snip> CUSTOM_PASSWORD=true net.ifnames=0 vga=0x317 lang=de quiet IP6=2a01:4f8:2220:14ac:: IP6MASK=64 IP6GW=fe80::1 config_url=https://admin-robot.your-server.de/admin/api/boot/rescue/4628558.Z2vZvg.khLl6Vr08_Im7RHgaq9gp1eLSrU-8qcdY4aCyg70uuk keyboard=ch BOOTIF=01-9c:6b:00:55:d5:d2

It looks like the IP6 address is injected to the kernel cmdline, but it's not clear if it can be accessed once the system is not in rescue mode anymore.

[zimbatm]

Hetzner Support

• https://docs.hetzner.com/robot/dedicated-server/ip/ip-basics#auto-configuration
• https://docs.hetzner.com/robot/dedicated-server/ip/additional-ip-adresses#slaac-ipv6

[zimbatm]

Talos

Only seeing Hetzner Cloud references: https://github.com/search?q=org%3Asiderolabs+hetzner&type=code&p=2