openstack/neutron
Code Issues Proposed changes

Update guest IPv6 information in docs

Browse Source 
Based on some recent questions on IPv6 address generation in
guests, update the relevant section in the docs to make it
more up-to-date.

Partial-bug: #1827489

Change-Id: Ibbf4d5458293c9c0269f6a80f5519caa175994ec
This commit is contained in:
Brian Haley 2019-05-03 09:49:18 -04:00
parent 4c4dc08c52
commit 252acc0694
1 changed files with 26 additions and 11 deletions
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37
doc/source/admin/config-ipv6.rst
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@ -416,23 +416,38 @@ overlap across the projects.
Security considerations
~~~~~~~~~~~~~~~~~~~~~~~
.. todo:: Initially this is probably just stating the security group rules
relative to IPv6 that are applied. Need some help for these
For more information about security considerations, see the ``Security groups``
section in
:doc:`intro-os-networking`.
Configuring interfaces of the guest
-----------------------------------
OpenStack currently doesn't support the privacy extensions defined by RFC 4941.
The interface identifier and DUID used must be directly derived from the MAC
as described in RFC 2373. The compute hosts must not be setup to utilize the
privacy extensions when generating their interface identifier.
OpenStack currently doesn't support the Privacy Extensions defined by RFC 4941,
or the Opaque Identifier generation methods defined in RFC 7217. The interface
identifier and DUID used must be directly derived from the MAC address
as described in RFC 2373. The compute instances must not be set up to utilize
either of these methods when generating their interface identifier, or
they might not be able to communicate properly on the network. For example,
in Linux guests, these are controlled via these two ``sysctl`` variables:
There is no provisions for an IPv6-based metadata service similar to what is
provided for IPv4. In the case of dual stacked guests though it is always
possible to use the IPv4 metadata service instead.
- ``net.ipv6.conf.*.use_tempaddr`` (Privacy Extensions)
- ``net.ipv6.conf.*.addr_gen_mode`` (link-local and autoconf address generation)
Unlike IPv4 the MTU of a given network can be conveyed in the RA messages sent
by the router as well as in the DHCP messages.
Both of these settings should be disabled (zero).
Other types of guests might have similar configuration options, please
consult your distribution documentation for more information.
There are no provisions for an IPv6-based metadata service similar to what is
provided for IPv4. In the case of dual-stacked guests though it is always
possible to use the IPv4 metadata service instead. IPv6-only guests will have
to use another method for metadata injection such as using a configuration
drive, which is described in the Nova documentation on
`config-drive <https://docs.openstack.org/nova/latest/user/config-drive.html>`__.
Unlike IPv4, the MTU of a given network can be conveyed in both the Router
Advertisement messages sent by the router, as well as in DHCP messages.
OpenStack control & management network considerations
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~