Routing on the Host user guide



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Sergei Hanus wrote:

In the user guide I see, that VM IP addresses are being redistributed into routing protocol.
Coul...

Eric, I totally agree with flexibility point.
As you said, for Docker there are options out-of-the-box (like adding /32 to loopback).
As for traditional vms - there's working solution from Cumulus (redistribute neighbor), which just needs to be "blessed", like you did for Quagga, in order to be ported to hypervisor - and we get out-of-the-box solution for traditional vms as well. That what I meant to point in my post.

Sergei.
Looking at the user guide, it appears RoH within a hypervisor (VMware, for example) is done via a router within the hypervisor, and not Quagga @ guest level. Am I correctly interpreting that? See: Subnet Freedom and Mobility diagram.
how does this integrate with KVM using openvswitch, would like to find out how to inject the routes when using bridges on vlans.
This is a good guide but can you possibly point me to one for the containerisation side of things? As a network guy getting a packet to the host is easy and running Quagga in a container to make the announcements makes perfect sense. The bit I'm struggling to articulate to the DevOps guys is how that packet gets to a container once it lands on the host without the host having the IP address configured on it beforehand! Should we for example, be running Quagga in every container, the next hop being a loopback address configured in the container? The DevOps-y way of solving all this seems to be bridges and ridiculously complicated (to me!) sequences of commands which just feels wrong. We're using RancherOS so anything Docker-like we should be able to adapt and hopefully find a common language!! Thanks!
Simon Woodhead wrote:

This is a good guide but can you possibly point me to one for the containerisation side of things...

Thanks Eric. This is about where we've ended up with a slight difference. Because we want a single prefix to span multiple hosts, we need to ensure that any container seeking to reach addresses in that prefix are routed away from the host rather than flooded out the relevant interface given there is no layer2 adjacency between them. The primary application for this is anycast but also the kind of mobility you describe without any specific host configuration.

We found this plugin (https://github.com/medallia/cnm-routed-plugin04377) which together with a priveleged container looks like it'll do the job. As you say, we'll use the host ip as the next hop rather than routing through Quagga.
Thanks again,
Simon

Simon Woodhead wrote:

This is a good guide but can you possibly point me to one for the containerisation side of things...

I'll check it out. Thanks!

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