Ensure floating IPs only use IPv4 addresses

[OpenStack Infra]

https://review.openstack.org/267891
Dear bug triager. This bug was created since a commit was marked with DOCIMPACT.
Your project "openstack/neutron" is set up so that we directly report the documentation bugs against it. If this needs changing, the docimpact-group option needs to be added for the project. You can ask the OpenStack infra team (#openstack-infra on freenode) for help if you need to.

commit 4858cd7cb97354ae54f8e7d47aeaaddad714c9dd
Author: Dustin Lundquist <email address hidden>
Date: Mon Jul 6 13:53:46 2015 -0700

    Ensure floating IPs only use IPv4 addresses

    Description:
    Presently Neutron doesn't validate the address family of floating IP
    addresses or the internal addresses they are associated with. It merely
    associates the first IP of the floating IP's port with the first IP of
    the internal port, unless a specified fixed IP is specified. This can
    lead to incorrect or poorly defined behavior when IPv6 is present.

    The existing L3 agent implementation only manages IPv4 NAT rules. While
    IPv6 NAT and NAT protocol translation are possible, the existing
    implementation does not support these configurations.

    Presently a floating IP can be created on an IPv6 only external network
    or associated with an IPv6 fixed IP, but the L3 agent is unable to bind
    these configurations.

    Implementation:
    When creating and updating a floating IP, only consider IPv4 addresses
    on both the floating IPs port and the internal port he floating IP is
    associated with. Additionally disallow creating floating IPs on networks
    without any IPv4 subnets, since these floating IPs could not be
    allocated an IPv4 address.

    DocImpact
    APIImpact

    Co-Authored-By: Bradley Jones <email address hidden>
    Change-Id: I79b28a304b38ecdafc17eddc41213df1c24ec202
    Related-Bug: #1437855
    Closes-Bug: #1323766
    Closes-Bug: #1469322
    (cherry picked from commit 4cdc71e7d0e5220a5f12ee2dfea1ff3db045c041)

[Boden R (boden)]

From a neutron perspective I'm not seeing anything needed.

However from an openstack-manuals POV it seems like we should note the IPv4 requirement for floating IPs (e.g. can't create floating IPs on net with no IPv4 subnets, etc. see commit message for more details). When searching the openstack docs I didn't find anything current talking about floating IPs, other than [1] (I think [1] is older).

Moving this over to openstack-manuals in hopes we can find somewhere to mention this requirement for floating IPs.

[1] http://docs.openstack.org/admin-guide/cli-admin-manage-ip-addresses.html

[YAMAMOTO Takashi (yamamoto)]

please note that there's a neutron plugin which uses ipv6 floating-ip for NAT64 functionality.
(networking-midonet, with fip64 extension.)

[Alexandra Settle (alexandra-settle)]

This is probably best updated in the admin guide:

DESCRIPTION: When creating and updating a floating IP, only consider IPv4 addresses on both the floating IPs port and the internal port he floating IP is associated with. Additionally disallow creating floating IPs on networks without any IPv4 subnets, since these floating IPs could not be allocated an IPv4 address.

[Joseph Robinson (joseph-r-email)]

For this bug, we can update the admin guide content now, while being aware that neutron content will most change location to the neutron dev team repository - https://etherpad.openstack.org/p/docs-i18n-ptg-pike-repos.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/462483

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/462483
Committed: https://git.openstack.org/cgit/openstack/openstack-manuals/commit/?id=2d7639a577422024336e5fd6740ebe99684029d0
Submitter: Jenkins
Branch: master

commit 2d7639a577422024336e5fd6740ebe99684029d0
Author: chenxing <[e-mail]>
Date: Thu May 4 10:29:27 2017 +0000

    [admin-guide] Add content about floating IPs only use IPv4 addresses

    Change-Id: I45cdf10f3ce3a57513a4673d03f94bd9951f148a
    Closes-Bug: #1577289