cloud-init fails to retrieve metadata over IPv6-only network

Cloud-init fails to retrieve instance metadata when operating in an IPv6-only environment. This leads to a complete failure of instance initialization in such setups, despite the metadata service being accessible over IPv6.

The issue has been observed even with the latest version of cloud-init and appears independent of any particular cloud provider. It affects environments that rely solely on IPv6 networking.

We welcome any assistance or collaboration in identifying and resolving the root cause of this problem.

A related report with more context is available here (All Informations):
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1104426

Best regards.