[libvirt-users] Two Node Cluster

[Alvin Starr]

Take a look at Madison Kellys' various blog postings at alteeve.com.

She has a generally very good set of how to's on how to build a 2 node 
cluster.


On 05/30/2018 10:32 AM, Cobin Bluth wrote:
> 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-unicast-endpoints/ )
>
> 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 at redhat.com
> https://www.redhat.com/mailman/listinfo/libvirt-users

-- 
Alvin Starr                   ||   land:  (905)513-7688
Netvel Inc.                   ||   Cell:  (416)806-0133
alvin at netvel.net              ||

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/libvirt-users/attachments/20180530/1cb46a4e/attachment.htm>