Proxmox cluster inside virtualbox

[kdeuser2025]

Hello, I am experimenting with proxmox cluster inside virtualbox. I have virtualbox runnong on ubuntu and two installation of proxmox inside virtualbox.
proxmox1 and proxmox2 use the same nat network (named myNatNetwork). each proxmox can reach the internet and can ping each other. However a vm inside promox1 cannot ping a vm inside proxmox2.

Can someone provide some help on setting up a c proxmox cluster inside virtualbox?

 

[Neobin]

Maybe this helps?:
https://pve.proxmox.com/wiki/Proxmox_VE_inside_VirtualBox

 

[UdoB]

Disclaimer: I am NOT a VirtualBox user, so my following text may be completely wrong for your situation.

Do NOT do NAT / masquerading. This destroys information by replacing native and valid IP addresses by the one of a proxy machine - a gateway.

In your current case there is no way to "ping" each other as the actual IP address is replaced by vbox.

This was invented by the devil when "real" (public) IP addresses were rare. You can hide a lot of machines behind one single address. In a LAN (and in more additional networks) you may establish in a homelab you want to use routing!

This is a requirement if you want to learn handling multiple networks or if you want to build a router. It is a must to see the actual IP address of a virtual machine (not a mangled replacement, used by several machines) to build a packet filter - as it needs to know the source- and the destination address.

For VirtualBox I am fairly sure you can use

a) a bridge to your normal LAN for the outgoing traffic. NAT will happen on your border gateway, e.g. a Fritz!Box but NOT on PVE and NOT on VirtualBox.

b) "Host-only" or "Local-only" networks for use in the PVE cluster. Note that these networks have no way to connect to the internet. You need some kind of a router for that.

Look at @Neobin 's link for more hints.

 

[kdeuser2025]

Thank you for the replies. I solved my issue by adding a second network adapter to both vm's inside proxmox. These adapter are bridges on a second interface of the proxmox instances which are configured with Host-Only network and by setting the routing correctly inside the test cm's.

192.168.56.1/24 -> go via interface 2 (Host-Only)
default -> go via interface 1 (Nat)