Open Stack

Hello Stackers!

It is very nice to watch the OpenStack evolution in IPv6! Great job guys!!


I have another idea:

"Floating IP" for IPv6, or just "Floating IPv6"


With IPv4, as we know, OpenStack have a feature called "Floating IP", which
is basically a 1-to-1 NAT rule (within tenant's Namespace q-router). In
IPv4 networks, we need this "Floating IP" attached to a Instance, to be
able to reach it from the Internet (*I don't like it*). But, what is the
use case for a "Floating IP" when you have *no NAT** (as it is with IPv6)?!

At first, when with IPv6, I was planning to disable the "Floating IP"
feature entirely, by removing it from Dashboard and from APIs (even for
IPv4, if FWaaS can in somehow, be able to manage q-router IPv4 NAT rules,
and not only the "iptables filter table") and, I just had an idea!

For IPv6, the "Floating IP" can still be used to allocate more (and more)
IPs to a Instance BUT, instead of creating a NAT rule (like it is for
IPv4), it will configure the DNSMasq (or something like it) to provide more
IPv6 address per MAC / Instance. That way, we can virtually
allocate unlimited IPs (v6) for each Instance!

It will be pretty cool to see the attached "Floating IPv6", literally
"floating around" the tenant subnet, appearing inside the Instances itself
(instead of inside the tenant's Namespace), so, we'll be able to see it
(the Floating IPv6) with "ip -6 address" command within the attached
Instance!

The only problem I see with this is that, for IPv4, the allocated
"Floating IPs"
come from the "External Network" (neutron / --allocation-pool) and, for IPv6,
it will come from the tenant's IPv6 subnet itself... I think... Right?!

---
Why I want tons of IPv6 within each Instance?

A.: Because we can! I mean, we can go back to the days when we had 1
website per 1 public IP (i.e. using IP-Based Virtual Hosts with Apache - I
prefer this approach).

Also, we can try to turn the "Floating IPv6", in some kind of "Floating
IPv6 Range", this way, we can for example, allocate millions of IPs per
Instance, like this in DHCPv6: "range6 2001:db8:1:1::1000
2001:db8:1:1000:1000;"...
---

NOTE: I prefer multiple IPs per Instance, instead of 1 IP per Instance,
when using VT, unless, of course, the Instances are based on Docker, so,
with it, I can easily see millions of tiny instances, each of it with its
own IPv6 address, without the overhead of virtualized environment. So, with
Docker, this "Floating IPv6 Range" doesn't seems to be useful...


* I know that there is NAT66 out there but, who is actually using it?! I'll
never use this thing. Personally I dislike NAT very much, mostly because it
breaks the end-to-end Internet connectivity, effectively kicking you out
from the real Internet, and it is just a workaround created to deal with
IPv4 exaustion.


BTW, please guys, let me know if this isn't the right place to post "ideas
for OpenStack / feature requests"... I don't want to bloat this list with
undesirable messages.


Best Regards,
Thiago Martins
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