[RFE] support ipv6 on servers serving release assets

[kranurag7]

Current situation

As of now, server that are serving release assets of flatcar doesn't work directly with ipv6. This means that when I'm using a builder to build flatcar inside a builder with ipv6 address only. This doesn't work.

Impact

Ref: apricote/flatcar-packer-hcloud#4

Ideal future situation

Supporting Ipv6 would help a lot and I won't be out of ipv4 addresses in my cloud provider. Actually many cloud providers provide you a limit that look you can only use 30 IPv4 public address. This means that when you're building machine images for different architecture and different flatcar versions, the permutations and combination of machines easily cross more than 30 machines in parallel. Supporting IPv6 only will avoid having this conflict in place.

Implementation options

I did had a look but the webpage says that the content is served using caddy but somehow I also think that it's nginx under the hood.

$ curl --verbose --ipv4 beta.release.flatcar-linux.net --head
* processing: beta.release.flatcar-linux.net
*   Trying 145.40.118.33:80...
* Connected to beta.release.flatcar-linux.net (145.40.118.33) port 80
> HEAD / HTTP/1.1
> Host: beta.release.flatcar-linux.net
> User-Agent: curl/8.2.1
> Accept: */*
>
< HTTP/1.1 200 OK
HTTP/1.1 200 OK
< Server: nginx
Server: nginx
< Date: Fri, 09 Aug 2024 07:52:23 GMT
Date: Fri, 09 Aug 2024 07:52:23 GMT
< Content-Type: text/html; charset=utf-8
Content-Type: text/html; charset=utf-8
< Connection: keep-alive
Connection: keep-alive

<
* Connection #0 to host beta.release.flatcar-linux.net left intact

So, not sure if you're using caddy for nginx under the hood.
Also, I don't have access to the infra that's serving this so this will probably needs to be done from the team managing the infra for flatcar.

Additional information

N/A (happy to answer more questions around it). This is not a urgent requirement for me.