[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
** Changed in: maas Milestone: next => None -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
https://www.freedesktop.org/software/systemd/man/systemd.network.html#VRF= VRF= The name of the VRF to add the link to. See systemd.netdev(5). vrf A Virtual Routing and Forwarding (VRF) interface to create separate routing and forwarding domains. [VRF] Section Options The [VRF] section only applies for netdevs of kind "vrf" and accepts the following key: Table= The numeric routing table identifier. This setting is compulsory. Example 15. /etc/systemd/network/25-vrf.netdev Create a VRF interface with table 42. [NetDev] Name=vrf-test Kind=vrf [VRF] Table=42 So there is backend support in networkd to create tables / vrf, and add link to a given vrf. Not sure about if routes are hooked up in networkd too. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
** Also affects: netplan.io (Ubuntu) Importance: Undecided Status: New ** Changed in: netplan.io (Ubuntu) Status: New => Confirmed ** Changed in: netplan.io (Ubuntu) Importance: Undecided => Medium -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
On Tue, May 05, 2020 at 06:04:28PM -, Billy Olsen wrote: > @bjornt Are you going to copy it over to the MAAS discourse feature set > then? We would prefer that one of the stakeholders actually would add it to discourse. That will ensure that the stakeholders are still in the loop, if there are questions about the feature. Otherwise it might be that the MAAS team will have a discussion with itself :) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
@bjornt Are you going to copy it over to the MAAS discourse feature set then? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
This sounds great, but it's not a bug report. It's a feature request. For MAAS, we track feature requests at https://discourse.maas.io/c/features, so I'm going to mark this bug report as Invalid for MAAS. ** Changed in: maas Status: Incomplete => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
** Tags added: sts -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
Sandor, Not on the VRF usage side but there is a feature in MAAS 2.6 to have a better way to work in multi-homed environments (for bionic+ machines): https://docs.maas.io/2.6/en/intro-new "Networking - Multiple default gateways" It relies on "routing policy database" (RPDB) functionality https://paste.ubuntu.com/p/xg6vFm8Hx7/ (netplan config, routing-policy sections are defined only for subnets that have a gateway configured in MAAS) At the target machine you will see something like this: # ip rule 0: from all lookup local 0: from 10.232.24.0/21 to 10.232.24.0/21 lookup main 0: from 10.232.40.0/21 to 10.232.40.0/21 lookup main 100:from 10.232.24.0/21 lookup 2 100:from 10.232.40.0/21 lookup 1 32766: from all lookup main 32767: from all lookup default # ip route show table 1 default via 10.232.40.1 dev b-enp4s0f0-2730 proto static # ip route show table 2 default via 10.232.24.1 dev b-enp4s0f0-2731 proto static This works well for TCP when responding to traffic (even when software listens on 0.0.0.0). For UDP a frequent server use-case is DNS servers and bind9 binds its UDP sockets to interface addresses directly as opposed to using 0.0.0.0 (some other DNS servers do the same, e.g. PowerDNS - they even have a post about it https://blog.powerdns.com/2012/10/08/on-binding-datagram-udp-sockets-to- the-any-addresses/). For sending, the policy rules will also kick in provided that a client socket (TCP or UDP) is bound to a specific address (so that the source IP is not automatically selected). This requires that the target software supports binding client sockets to specific addresses unfortunately. So far using static routes to summarized prefixes has been a solution for east-west traffic (because we control nodes managed by MAAS) and using the approach above for client responses to arbitrary networks (via https://jaas.ai/u/canonical-bootstack/policy-routing). After juju starts supporting this new MAAS feature https://bugs.launchpad.net/juju/+bug/1829150 we can stop using charm- policy-routing. I hope that helps while VRF functionality is not implemented. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
Any news or progress on these issues now that we are a year and a half into this bug? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
BUMP! +1000 for this feature. We need vrf support in MAAS to be able to use it with in bgp/vrf stack. @dmitriis thank you for the thorough write up and detailed explanation of the problem/solution here! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
John, Interfaces of a host carry enough information to be used to make routing decisions - that's the core idea of host and router-side VRF implementations. Network spaces as of now do not help you to solve routing problems in any way unless you have one big L2 network and "routing" is done without routers: via ARP/NDP in a single broadcast domain. Static routes are not flexible enough and are a workaround for the lack of VRF support. They require many additional steps from a deployer's perspective to worry about: one should just take a set of VLANs and subnets to configure in MAAS and assign them to a network space. With a default gateway per subnet there is always a next hop to delegate a routing decision to for a given network space from a host's perspective. Charms and potentially applications do need to be VRF-aware (discussed above on how). BGP on a host, while feasible in some scenarios, is not always doable in practice: not every network and/or security department will give you an ability to deploy something and set up peering with their BGP-enabled routers. I'd be happy to discuss scenarios in-depth here or out of band but the idea is that Network Spaces need to learn how to assist with Routing and Forwarding parts - currently they solve only end-end discovery via relation data. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
It would be good to have a clearer discussion of what issues you are running into with routes. There are several ways that we *could* tackle the issue. Static Routes was the mechanism that we started modeling because that was the ask from the field (because, as-I-understand, that was the solution they were using manually). There have been discussions about enabling things like BGP. It would be possible to push heavier on the modeling aspect, and give ways to model routing as part of the network and space model, and then have Juju tracking and updating those (eg, route traffic from this space to that space via these gateways). On Fri, Jan 26, 2018 at 7:42 PM, Sandor Zeestraten wrote: > I'd like to chime in and add that this is something that we've been > missing in our Juju and MAAS deployment of OpenStack. > > One of our problem area for example is properly routing management, > storage and public traffic for our OpenStack deployment without complex > static rules and a lot of annoying workarounds. > > I hope that both the Juju and MAAS team take a proper look at supporting > these use cases. > > -- > You received this bug notification because you are subscribed to the bug > report. > https://bugs.launchpad.net/bugs/1737428 > > Title: > VRF support to solve routing problems associated with multi-homing > > To manage notifications about this bug go to: > https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions > -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
I'd like to chime in and add that this is something that we've been missing in our Juju and MAAS deployment of OpenStack. One of our problem area for example is properly routing management, storage and public traffic for our OpenStack deployment without complex static rules and a lot of annoying workarounds. I hope that both the Juju and MAAS team take a proper look at supporting these use cases. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
Marking as Incomplete Wishlist as per 'maas' ** Changed in: juju Status: New => Incomplete ** Changed in: juju Importance: Undecided => Wishlist -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
Andres, I'm not going to be at the sprint but the problems described need a proper solution in MAAS and Juju at least from the end host perspective. Similar to how VLANs are supported natively in MAAS & Juju, L3 virtualization technologies like VRF should be as well. I hope the information I will give here will be enough to understand the use-cases and past experience in this field. The concept is very similar to VLANs but for L3 which is probably less familiar and spans many hosts and routers/L3 switches within a single organization instead of being tied to a given switch fabric and either the same process or a group of processes on a host need to (1) receive & respond and (2) send data using different L3 topologies. Instead of virtual broadcast domains you get virtual paths because of per- virtual-L3 routing topologies. Good L2 analogies are Multiple Spanning Tree Protocol (MSTP) or PVST+ that were created to avoid blocking of switchports depending on logical L2 topologies related to a VLAN or group of VLANs (this is hidden on L2 though - no end host modifications required). The use-cases I am talking about are not new - they were not used as much in data center networks until a certain point. They were used in service provider networks for multi-site L3 VPN for many years (https://tools.ietf.org/html/rfc4364). There are still many deployments which rely on large L2 domains where those problems do not occur as much because routing is done trivially via using directly connected routes and ARP broadcasts (there is never a hop between a source and destination host in most cases). I may be wrong but it seems to me that Network Spaces were originally designed with multi-homing in mind but with limited support for multi-L2 and routing in mind (I don't judge, VRFs are fairly new to the Linux kernel). They are not that far from supporting that though because of the recent upstream kernel work. With leaf-spine you are building a complex L3 network with different virtual topologies for different purposes and different SLAs for various kinds of traffic (IOW, a multi-tenant network). This is a typical service provider scenario with different customers on a shared infrastructure. You need to build many parallel dedicated communication lines but since infrastructure is shared it is not possible physically, however, you still need to do load-sharing across links, use distinct paths for different kinds of traffic and other optimizations to make sure your physical links are utilized and clients get certain quality of service and are separated from each other. In this case L3 VPNs are built not for clients (companies "x" and "y") but for different purposes: general purpose data, storage access or replication, management, public API traffic (originally, this was done for voice/video/data, see the first two paragraphs in the "background" section https://www.google.ch/patents/US8457117). I can describe this in many ways, i.e. we need: * multi-point L3VPN between racks to simulate L3 virtual circuits/pseudowires for different types of traffic; * virtual routing domains (VRFs); * traffic and routing separation for multi-L2 segment networks; * L3 network multi-tenancy. This is definitely not new, the service provider concepts may be less familiar though: 1) Static routes + VLSM - DIY routing - doesn't scale and difficult to manage when a deployment grows beyond the original VLSM design; 2) VRF-lite (VRF without MPLS) - separate address spaces and routing tables for different traffic on routers and, potentially, hosts, interface-based selection of a VRF on a given network device; 3) MPLS - this is like VXLAN for virtual L3 networks. In a service provider network two MPLS labels are used: one for VRF identification and another one for next-hop router identification (in a data center network think of an internal or public API label, storage access label, storage replication label etc.). This has been used for years to separate out traffic of different customers or, for example, general purpose data, voice and video for a single customer. Containers do not solve this problem with a separate network namespace because the same process or a group of processes need to use a different routing table "per-purpose". What I am asking for is not that difficult because we are only concerned with end hosts (unless MAAS resides on a ToR or a leaf and we control the switch OS). I need building blocks to use either VRF-lite or full VRFs with MPLS in a sane way while keeping routing complexity (BGP, MPLS etc.) in a data center provider network managed by other people. Terminology-wise, I think changes are needed as well: https://github.com/CanonicalLtd/maas-docs/issues/737 - Routing Domain, L3VPN or VRF are common names for what we refer to as a Network Space, and what is actually a virtual L3 network with its own complete address space, routing table copies and dedicated host/router physical or logical interfaces. Examples:
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
** Description changed: Problem description: * a host is multi-homed if it has multiple network interfaces with L3 addresses configured (physical or virtual interfaces, natural to OpenStack regardless of IPv4/IPv6 and IPv6 in general); + + (see 3.3.4 Local Multihoming + https://tools.ietf.org/html/rfc1122#page-60 and 3.3.4.2 Multihoming + Requirements) * if all hosts that need to participate in L3 communication are located on the same L2 network there is no need for a routing device to be present. ARP/NDP and auto-created directly connected routes are enough; * multi-homing with hosts located on different L2 networks requires more intelligent routing: - "directly connected" routes are no longer enough to talk to all relevant hosts in the same network space; - a default gateway in the main routing table may not be the correct routing device that knows where to forward traffic (management network traffic goes to a management switch and router, other traffic goes to L3 ToR switch but may go via different bonds); - even if a default gateway knows where to forward traffic, it may not be the intended physical path (storage replication traffic must go through a specific outgoing interface, not the same interface as storage access traffic although both interfaces are connected to the same ToR); - there is no longer a single "default gateway" as applications need either per-logical-direction routers or to become routers themselves (if destination == X, forward to next-hop Y). Leaf-spine architecture is a good example of how multiple L2 networks force you to use spaces that have VLANs in different switch fabrics => one or more hops between hosts with interfaces associated with the same network space; - while network spaces implicitly require L3 reachability between each host that has a NIC associated with a network space, the current definition does not mention routing infrastructure required for that. For a single L2 this problem is hidden by directly connected routes, for multi-L2, no solution is provided or discussed; * existing solutions to multi-homing require routing table management on a given host: complex static routing rules, dynamic routing (e.g. running an OSPF or BGP daemon on a host); * using static routes is rigid and requires network planning (i.e. working with network engineers which may have varying degrees of experience, doing VLSM planning etc.); * using dynamic routing requires a broader integration into an organization's L3 network infrastructure. Routing can be implemented differently across different organizations and it is a security and operational burden to integrate with a company's routing infrastructure. Summary: a mechanism is needed to associate an interface with a forwarding table (FIB) which has its own default gateway and make an application with a listen(2)ing socket(2) return connected sockets associated with different FIBs. In other words, applications need to implicitly get source/destination-based routing capabilities without the need to use static routing schemes or dynamic routing and with minimum or no modifications to the applications themselves. Goals: * avoid turning individual hosts into routers; * avoid complex static rules; * better support multi-fabric deployments with minimum effort (Juju, charms, MAAS, applications, network infrastructure); * reduce operational complexity (custom L3 infrastructure integration for each deployment); * reduce delivery risks (L3 infrastructure, L3 department responsiveness varies); * avoid any form of L2 stretching at the infrastructure level - this is inefficient for various reasons. NOTE: https://cumulusnetworks.com/blog/vrf-for-linux/ - I recommend to read this post to understand suggestions below. How to solve it? What does it mean for Juju to support VRF devices? * enslave certain devices on provisioning based on network space information (physical NICs, VLAN devices, bonds AND bridges created for containers must be considered) - VRF devices logically enslave devices similar to bridges but work differently (on L3, not L2); * the above is per network namespace so it will work equally well in a LXD container; Conceptually: # echo 'net.ipv4.tcp_l3mdev_accept = 1' >> /etc/sysctl.conf # echo 'net.ipv4.udp_l3mdev_accept = 1' >> /etc/sysctl.conf # sysctl -p # # create additional routing tables # cat >> /etc/iproute2/rt_tables.d/vrf.conf
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
** Tags added: kernel-da-key ** Changed in: linux (Ubuntu) Importance: Undecided => Wishlist -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
Hi Dimitrii, This request seems like something we have never seen before. This doesn't seem to be quite a complex thing to do. Right now, this is and never has been in our plans to implement. This is also something that has never come up before. I'm going to mark this as a wishlist, and incomplete, until we understand what are the needs and the impact on the project. I would suggest you raise this during the sprint. ** Changed in: maas Status: New => Incomplete ** Changed in: maas Importance: Undecided => Wishlist ** Changed in: maas Milestone: None => next -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
** Description changed: Problem description: * a host is multi-homed if it has multiple network interfaces with L3 addresses configured (physical or virtual interfaces, natural to OpenStack regardless of IPv4/IPv6 and IPv6 in general); * if all hosts that need to participate in L3 communication are located on the same L2 network there is no need for a routing device to be present. ARP/NDP and auto-created directly connected routes are enough; * multi-homing with hosts located on different L2 networks requires more intelligent routing: - - "directly connected" routes are no longer enough to talk to all relevant hosts in the same network space; - - a default gateway in the main routing table may not be the correct routing device that knows where to forward traffic (management network traffic goes to a management switch and router, other traffic goes to L3 ToR switch but may go via different bonds); - - even if a default gateway knows where to forward traffic, it may not be the intended physical path (storage replication traffic must go through a specific outgoing interface, not the same interface as storage access traffic although both interfaces are connected to the same ToR); - - there is no longer a single "default gateway" as applications need either per-logical-direction routers or to become routers themselves (if destination == X, forward to next-hop Y). Leaf-spine architecture is a good example of how multiple L2 networks force you to use spaces that have VLANs in different switch fabrics => one or more hops between hosts with interfaces associated with the same network space; - - while network spaces implicitly require L3 reachability between each host that has a NIC associated with a network space, the current definition does not mention routing infrastructure required for that. For a single L2 this problem is hidden by directly connected routes, for multi-L2, no solution is provided or discussed; + - "directly connected" routes are no longer enough to talk to all relevant hosts in the same network space; + - a default gateway in the main routing table may not be the correct routing device that knows where to forward traffic (management network traffic goes to a management switch and router, other traffic goes to L3 ToR switch but may go via different bonds); + - even if a default gateway knows where to forward traffic, it may not be the intended physical path (storage replication traffic must go through a specific outgoing interface, not the same interface as storage access traffic although both interfaces are connected to the same ToR); + - there is no longer a single "default gateway" as applications need either per-logical-direction routers or to become routers themselves (if destination == X, forward to next-hop Y). Leaf-spine architecture is a good example of how multiple L2 networks force you to use spaces that have VLANs in different switch fabrics => one or more hops between hosts with interfaces associated with the same network space; + - while network spaces implicitly require L3 reachability between each host that has a NIC associated with a network space, the current definition does not mention routing infrastructure required for that. For a single L2 this problem is hidden by directly connected routes, for multi-L2, no solution is provided or discussed; * existing solutions to multi-homing require routing table management on a given host: complex static routing rules, dynamic routing (e.g. running an OSPF or BGP daemon on a host); * using static routes is rigid and requires network planning (i.e. working with network engineers which may have varying degrees of experience, doing VLSM planning etc.); * using dynamic routing requires a broader integration into an organization's L3 network infrastructure. Routing can be implemented differently across different organizations and it is a security and operational burden to integrate with a company's routing infrastructure. Summary: a mechanism is needed to associate an interface with a forwarding table (FIB) which has its own default gateway and make an application with a listen(2)ing socket(2) return connected sockets associated with different FIBs. In other words, applications need to implicitly get source/destination-based routing capabilities without the need to use static routing schemes or dynamic routing and with minimum or no modifications to the applications themselves. Goals: * avoid turning individual hosts into routers; * avoid complex static rules; * better support multi-fabric deployments with minimum effort (Juju, charms, MAAS, applications, network infrastructure); * reduce operational complexity (custom L3 infrastructure integration for each deployment); * reduce delivery risks (L3 infrastructure, L3 department responsiveness varies); * avoid any form of L2 stretching at the infra
[Bug 1737428] Re: VRF support to solve routing problems associated with multi-homing
For Ubuntu kernel this is a backport request. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1737428 Title: VRF support to solve routing problems associated with multi-homing To manage notifications about this bug go to: https://bugs.launchpad.net/juju/+bug/1737428/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs