[openstack-dev] Configuring ISC dhclient on guest to acquire ipv6 default gateway
veremin at mirantis.com
Tue Dec 29 09:45:28 UTC 2015
You’re seeing default route as a link-local address of router just because the routing things is working this way in IPv6 in general, not in OpenStack. gateway_ip is actually set on router interface, and could be reachable, and actually valid choice for routing, but there is no way (and it makes no sense) to automatically configure router’s GUA as a default gateway address.
With best regards,
Fuel Deployment Engineer,
> On Dec 28, 2015, at 6:35 PM, Andrei Radulescu-Banu <andrei.radulescu-banu at exfo.com> wrote:
> Thanks for your help, Vladimir. You are right, now that I look more closely, in dhcpv6-stateful mode the default gateway is acquired through router advertisement (instead of dhcp6 options). And the default gateway I get is the link-local address instead of the configured gateway_ip of 1:2:3:4::1.
> This was confusing, to say the least - and not well explained anywhere - but it is working. I've tested all three modes of configuration (ipv6_address_mode and ipv6_ra_mode both simultaneously set to dhcpv6-stateful, dhcpv6-stateless or slaac). In all cases I am acquiring a default gateway - and it is the link local address of the default gateway. I can tell it works because the default gateway is pingable through the interface, and the low 3 bytes of the default gateway ip6 address matches the low 3 bytes of the gateway MAC address. (The MAC address is viewable when reviewing the router interfaces through the Horizon UI, for example - the actual link local ip6 addresses of the default gateway are not displayed).
> Message: 2
> Date: Fri, 25 Dec 2015 19:07:31 +0300
> From: Vladimir Eremin <veremin at mirantis.com>
> To: "OpenStack Development Mailing List (not for usage questions)"
> <openstack-dev at lists.openstack.org>
> Subject: Re: [openstack-dev] Configuring ISC dhclient on guest to
> acquire ipv6 default gateway
> Message-ID: <5864AF60-644C-438E-9D82-80C4FCED1137 at mirantis.com>
> Content-Type: text/plain; charset=utf-8
> Hi Andrei,
> Default gateways for IPv6 is always configured with Router Advertisements (RA), no matter what addressing mode is used. Please ensure that:
> - you have a virtual router connected to your IPv6 subnet, this would provide RA (and actual router) in your network
> - accept_ra is enabled in your guest OS: sysctl -a | grep accept_ra
> With best regards,
> Vladimir Eremin,
> Fuel Deployment Engineer,
> Mirantis, Inc.
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