Cloud metadata over a v6 only link

[Thomas Goirand <zigo@debian.org>]

Hi,

We discussed it before, and I wasn't sure about the status of $subject
in OpenStack. However, now I know. After this patch was merged (6 hours
ago), OpenStack is now capable of providing instance metadata over IPv6:

https://review.opendev.org/#/c/715482/

This means that, in such case, having a v6 only capable image does make
sense, at least for OpenStack. My take is that, sooner or later, we will
have the same needs for other clouds, so it'd be nice if we could figure
out how.

Can someone remind me what was the issue in our image? If I remember
correctly, cloud-init will wait for DHCP over IPv4 before reading the
metadata?

Anyway, once OpenStack Victoria is out (mid-october), and I get it
packaged, I'll be able to test all of this.

Cheers,

Thomas Goirand (zigo)