Re: [libvirt-users] Two Node Cluster

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: https://i.imgur.com/SOk6a6G.png I would like to configure the following details: - Each node has a DHCP enabled guest network where VMs will run. (eg, *192.168.1.0/24 <http://192.168.1.0/24>* for Host1, and *192.168.2.0/24 <http://192.168.2.0/24>* 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 192.168.2.0/24 <http://192.168.2.0/24> via 172.20.0.1* - Configured route on Host2 also: *ip route add 192.168.1.0/24 <http://192.168.1.0/24> via 172.20.0.2* - 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'/>* 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: https://joejulian.name/post/how-to-configure-linux-vxlans-with-multiple-u...) 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? _______________________________________________ libvirt-users mailing list libvirt-users(a)redhat.com https://www.redhat.com/mailman/listinfo/libvirt-users