Open Stack

Hello,

Here is a little feedback of what we did.

We kept our VMs connected to a VLAN network and we activated SLAAC on the corresponding IRB on our router. We then configured the subnet with SLAAC for external router : VMs receives RA (and RDNSS). They now have an IP, the gateway is a link local address of our datacenter router. Everything is working fine.

I have to add that we were having some issues: we couldn’t ping VMs from our router for instance. We added two rules in the default security group (INGRESS and EGRESS, All ICMP on ::/0). Now, it is working fine.

As you said, this paradigm is the most simple one and is working just fine. We’ll continue our testing with this.

For everything, thank you.

Marc-Antoine


> Le 9 mars 2022 à 18:13, Brian Haley <haleyb.dev at gmail.com> a écrit :
> 
> Hi,
> 
> On 3/8/22 21:08, Marc-Antoine Godde wrote:
>> Hello,
>> Indeed, this network is connected to our physical network (VLAN 51 for testing), xxxx:xxxx:2f1:aaaa::1 is an interface on our physical router.
>> Finally, we successfully started RADVD by adding a network interface in the subnet to a virtual router in OpenStack. This gave IPs to VMs, they were able to communicate between each other. Obviously, this network topology isn’t making any sense, we can’t route traffic outside. It was just for testing.
>> Now, the goal is route the traffic of VMs. I see two paradigms. The first one, we use our physical router to send RA directly to VMs.
> 
> This is going to be the quickest and easiest way to do this - having the VM directly attached to your infrastructure and having them create a SLAAC address based on the RA from that router.
> 
>> The second one, we use a private subnet (xxxx:xxxx:2f1:bbbb::/64 for instance) in a non external network of OpenStack. We add a virtual router to that subnet, we now have RADVD. We use that router to route traffic to an external network of OpenStack. What is best ?
> 
> This is possible, but requires using prefix delegation such that the private network gets an IPv6 prefix that is routeable in your datacenter. This is described on the docs page at [0] but does require that your infrastructure supports IPV6-PD.
> 
> -Brian
> 
> [0] https://docs.openstack.org/neutron/latest/admin/config-ipv6.html
> 
>>> Le 8 mars 2022 à 23:47, Brian Haley <haleyb.dev at gmail.com <mailto:haleyb.dev at gmail.com>> a écrit :
>>> 
>>> Hi Marc-Antoine,
>>> 
>>> See inline...
>>> 
>>> On 3/8/22 11:18, Marc-Antoine Godde wrote:
>>>> Hi,
>>>> Here’s what we’ve done.
>>>> We created a network:
>>>> Name
>>>>    ipv6-testing-network
>>>> ID
>>>>    9d5ca309-1861-4422-bcff-8818f9762a6f
>>>> Project ID
>>>>    653f5a2e60d34768a8629e5d4fca0738
>>>> Status
>>>>    Active
>>>> Admin State
>>>>    UP
>>>> Shared
>>>>    Yes
>>>> External Network
>>>>    Yes
>>>> MTU
>>>>    1500
>>>> Provider Network
>>>>    Network Type: vlan
>>>>    Physical Network: vlan
>>>>    Segmentation ID: 51
>>> 
>>> So this is an external provider network connected to your datacenter network, correct? In the case Slawek was describing I believe he was talking about an internal private network, which when a neutron router is attached will trigger radvd to be spawned, etc.
>>> 
>>> In this case VMs booted on this network should be seeing RAs from your datacenter router, if it's sending them. If it's not that would explain why they only have a link-local IPv6 address since the neutron router will not spawn radvd to run on the external network.
>>> 
>>> BTW, I'm trying to compare this to my local setup, but since I'm not running Horizon just using 'openstack network show...', 'openstack subnet show...' output, which is slightly different, but looks to match what you're doing.
>>> 
>>> Is your plan to have private IPv6 subnets that are then routed to your external network or is this just a test?
>>> 
>>> -Brian
>>> 
>>> 
>>>> We created a subnet:
>>>> Name
>>>>    ipv6-testing-v6
>>>> ID
>>>>    763771d4-b9d7-419a-ba04-97ce3abaf152
>>>> Project ID
>>>>    653f5a2e60d34768a8629e5d4fca0738
>>>> Network Name
>>>>    ipv6-testing-network
>>>> Network ID
>>>>    9d5ca309-1861-4422-bcff-8818f9762a6f
>>>>    <https://openstack.viarezo.fr/project/networks/9d5ca309-1861-4422-bcff-8818f9762a6f/detail <https://openstack.viarezo.fr/project/networks/9d5ca309-1861-4422-bcff-8818f9762a6f/detail>>
>>>> Subnet Pool
>>>>    None
>>>> IP Version
>>>>    IPv6
>>>> CIDR
>>>>    xxxx:xxxx:2f1:aaaa::/64
>>>> IP Allocation Pools
>>>>    Start xxxx:xxxx:2f1:aaaa::2 - End xxxx:xxxx:2f1:aaaa:ffff:ffff:ffff:ffff
>>>> Gateway IP
>>>>    xxxx:xxxx:2f1:aaaa::1
>>>> DHCP Enabled
>>>>    Yes
>>>> IPv6 Address Configuration Mode
>>>>    SLAAC: Address discovered from OpenStack Router
>>>> Additional Routes
>>>>    None
>>>> DNS Name Servers
>>>>    None
>>>> We created Ubuntu and Debian instances. According to Horizon, the instance IPv6 is xxxx:xxxx:2f1:aaaa:f816:3eff:fe6d:c41a. Yet, we only have a link local address which is fe80::f816:3eff:fe6d:c41a/64. TCPdump indicates no Router Advertisement. We tried with and without adding a router on the Network in Horizon. ICMPv6 is authorized in INGRESS from ::/0.
>>>> We checked on the controllers, the computes and in the Neutron containers, systemctl indicated no instance of RADVD. Maybe we checked incorrectly...
>>>> Do you have any suggestions ? I add that we are working with OpenStack Ussuri deployed with OpenStack-ansible.
>>>> Thanks,
>>>> Marc-Antoine
>>>>> Le 8 mars 2022 à 08:59, Slawek Kaplonski <skaplons at redhat.com <mailto:skaplons at redhat.com><mailto:skaplons at redhat.com <mailto:skaplons at redhat.com>>> a écrit :
>>>>> 
>>>>> Hi,
>>>>> 
>>>>> On poniedziałek, 7 marca 2022 10:36:30 CET Marc-Antoine Godde wrote:
>>>>>> Hello,
>>>>>> 
>>>>>> Thanks for your answer.
>>>>>> 
>>>>>> If I’m correct, we can just use a virtual router with SLAAC since RADVD can deal with RS and emit RA (with support for RFC6106), right ?
>>>>> 
>>>>> Yes, virtual router created in the Neutron is enough there. It will spawn radvd in the qrouter namespace and will send RA to the Vms.
>>>>> Please note that Neutron don't supports privacy extension [1] so You will need to make sure that it's disabled it on Your vms.
>>>>> 
>>>>>> More generally, aren’t we suppose to have a virtual router every time, even in DHCPv6 (stateless and statefull), to answer RS ? I have to admit that I’m not very familiar at the moment with the implementations of RFCs in OpenStack.
>>>>>> 
>>>>>> Currently, we prefer the idea of adding IPv6 through SLAAC to have a uniform network. If we do so, we’d like to avoid sending RA from our physical router to limit its load. Yet, we do not any other arguments to support this choice.
>>>>>> Do you have any recommendations on what to do in latest versions of OpenStack ? What is usually done ?
>>>>> 
>>>>> TBH I don't have such experience. That's more question to operators of OpenStack.
>>>>> 
>>>>>> 
>>>>>> Thanks,
>>>>>> Marc-Antoine
>>>>>> 
>>>>>>> Le 7 mars 2022 à 09:12, Slawek Kaplonski <skaplons at redhat.com <mailto:skaplons at redhat.com><mailto:skaplons at redhat.com <mailto:skaplons at redhat.com>>> a écrit :
>>>>>>> 
>>>>>>> Hi,
>>>>>>> 
>>>>>>> On poniedziałek, 7 marca 2022 02:36:24 CET Marc-Antoine Godde wrote:
>>>>>>>> Hello.
>>>>>>>> 
>>>>>>>> We are progressively adding support for IPv6 in my company. We decided to use SLAAC only for laptops, phones, … since DHCPv6 isn’t supported on Android. RDNSS support will also increase. We are now planning our deployment on OpenStack. We already know that we'll rely only on neutron but we are not yet fixed between DHCPv6 and SLAAC ? Do you have any arguments for one these for VMs ?
>>>>>>>> 
>>>>>>>> Thanks,
>>>>>>>> Marc-Antoine.
>>>>>>>> 
>>>>>>> 
>>>>>>> With SLAAC You need to have Your network connected to the router in Neutron and You can only configure IP address on the VM. With DHCPv6 You can configure other things, like some static-routes, etc.
>>>>>>> Neutron supports DHCPv6 in the stateful and stateless variants. With stateless, You are using RA for address configuration and DHCP server for other configation. Please see [1] for more details.
>>>>>>> 
>>>>>>> [1]https://docs.openstack.org/neutron/latest/admin/config-ipv6.html#address-modes-for-ports <https://docs.openstack.org/neutron/latest/admin/config-ipv6.html#address-modes-for-ports><https://docs.openstack.org/neutron/latest/admin/config-ipv6.html#address-modes-for-ports <https://docs.openstack.org/neutron/latest/admin/config-ipv6.html#address-modes-for-ports>>
>>>>>>> 
>>>>>> 
>>>>>> 
>>>>> 
>>>>> [1]https://datatracker.ietf.org/doc/html/rfc4941 <https://datatracker.ietf.org/doc/html/rfc4941><https://datatracker.ietf.org/doc/html/rfc4941 <https://datatracker.ietf.org/doc/html/rfc4941>>
>>>>> 
>>>>> --
>>>>> Slawek Kaplonski
>>>>> Principal Software Engineer
>>>>> Red Hat
>