Support IPv6

[kema-dev]

Description

• Currently, a /32 suffix is appended to PROVISIONING_IP, preventing usage for IPv6.
• We could also consider making it possible to add 2 IPs in virtual_ipaddress for IPv6, one LLA and one routable.

Possible solution

• Detect IP format and append either /32 or /128 accordingly. Maybe do not append anything (is the /32 needed ?)
• Eventually allow multiple IPs, comma separated or w/e

What do you think ? I can make a fixup PR if relevant to you

[tuminoid]

@Rozzii @nuhakala @terror96 PTAL

[Rozzii]

/triage accepted
/kind feature

[nuhakala]

This was actually a problem for me when I was implementing IPv6 support, and I used this branch to make it work, never made a PR however, probably because the IPv6 support is still lacking, and my implementation is just something I made quickly to get it working.

The important thing to notice with the IPv6 addresses and keepalived is, that keepalived requires two IP addresses configured on the interface with v6. With v4 it works fine with the current configuration, but as you can see in my branch, I added link local address there, because otherwise keepalived would error.

Not sure if any CIDR needs to be appended to the address. I used /64 in the link local and that worked fine, I guess this could be checked from keepalived man page.

Having a PR to fix this would be awesome, as this is needed to run the dev env with IPv6.