<div dir="ltr">Hello Libvirt Users, I would like to setup a two node bare-metal cluster. I need to guidance on the network configuration. I have attached a small diagram, the same diagram can be seen here: <a href="https://i.imgur.com/SOk6a6G.png">https://i.imgur.com/SOk6a6G.png</a> I would like to configure the following details: - Each node has a DHCP enabled guest network where VMs will run. (eg, <a href="http://192.168.1.0/24">192.168.1.0/24</a> for Host1, and <a href="http://192.168.2.0/24">192.168.2.0/24</a> for Host2) - Any guest in Host1 should be able to ping guests in Host2, and vice versa. - All guests have routes to reach the open internet (so that 'yum update' will work "out-of-the-box") - Each node will be able to operate fully if the other physical node fails. (no central DHCP server, etc) - I would like to add more physical nodes later when I need the resources. This is what I have done so far: - Installed latest Ubuntu 18.04, with latest version of libvirt and supporting software from ubuntu's apt repo. - Each node can reach the other via its own eth0. - Each node has a working vxlan0, which can ping the other via its vxlan0, so it looks like the vxlan config is working. (I used ip link add vxlan0 type vxlan...) - Configured route on Host1 like so: ip route add <a href="http://192.168.2.0/24">192.168.2.0/24</a> via 172.20.0.1 - Configured route on Host2 also: ip route add <a href="http://192.168.1.0/24">192.168.1.0/24</a> via 172.20.0.2<div>- All guests on Host1 (and Host1) can ping eth0 and vxlan0 on Host2, and vice versa, yay. - Guests on Host1 cannot ping guests on Host2, I suspect because the the default NAT config of the libvirt network. So, at this point I started to search for tutorials or more information/documentation, but I am a little overwhelmed by the sheer amount of information, as well as a lot of "stale" information on blogs etc. I have learned that I can virsh net-edit default, and then change it to an "open" network: <forward mode='open'/></div><div>After doing this, the guests cannot reach outside their own network, nor reach the internet, so I assume that I would need to add some routes, or something else to get the network functioning like I want it. There is also <forward mode="route"/>, but I dont fully understand the scenarios where one would need an open or a route forward mode. I have also shied away from using openvswitch, and have opted for ifupdown2. (I have taken most of my inspiration from this blog post: <a href="https://joejulian.name/post/how-to-configure-linux-vxlans-with-multiple-unicast-endpoints/">https://joejulian.name/post/how-to-configure-linux-vxlans-with-multiple-unicast-endpoints/</a> ) Some questions that I have for the mailing list, any help would be greatly appreciated: - Is my target configuration of a KVM cluster uncommon? Do you see drawbacks of this setup, or does it go against "typical convention"? - Would my scenario be better suited for an "open" network or a "route" network? - What would be the approach to complete this setup? </div></div>