Two virtual networks


This document expects you to have set up OpenVNet according to the installation guide, created the simple single network and set up its DHCP server. We will be continuing from there so complete those guides first.

In this guide we will set up a second virtual network and move inst2 to it. We'll also set up a new DHCP server for that network. That will give us the following topology.

Two networks


The first two steps are similar to what we have done before. Create a new network and setup its simulated DHCP service.

Create the new network

vnctl networks add \
  --uuid nw-test2 \
  --display-name testnet2 \
  --ipv4-network \
  --ipv4-prefix 24 \
  --network-mode virtual

Set up its DHCP server

vnctl interfaces add \
  --uuid if-dhcp2 \
  --mode simulated \
  --owner-datapath-uuid dp-test1 \
  --mac-address 02:00:00:00:01:12 \
  --network-uuid nw-test2 \

vnctl network-services add \
  --uuid ns-dhcp2 \
  --interface-uuid if-dhcp2 \
  --type dhcp

Move inst2 to the new network

There are two ways to do this.

  • The quick and dirty way. Remove the interface and re-create it.

  • The clean but slightly harder way. Dig a little deeper into OpenVNet's inner workings make only the required changes.

Choose one of the two two ways below.

The quick and dirty way.

To keep things simple, we will just remove inst2 from OpenVNet's database and re-create it.

A side effect of this method is that we will not be able to use the same UUID. That's because OpenVNet's database uses logical delete. Deleted records aren't actually removed but only marked as deleted. Their unique fields cannot be reused.

vnctl interfaces del if-inst2

Now re-create it. Since we can't reuse the UUID if-inst2, we'll use if-newinst2.

vnctl interfaces add \
  --uuid if-newinst2 \
  --mode vif \
  --owner-datapath-uuid dp-test1 \
  --mac-address 10:54:ff:00:00:02 \
  --network-uuid nw-test2 \
  --ipv4-address \
  --port-name inst2

You're done. Move on to the test section.

The clean but slightly harder way

We've now created several network interfaces in OpenVNet using the vnctl interfaces add command. Actually every time we call that command, OpenVNet creates several fields in the database to keep track of MAC address, IP address, network assignment etc. The field we need to change here is ip lease.

First have a look at inst2's interface.

vnctl interfaces show if-inst2

As you can see, there's quite a bit of information to be had here. The part we're interested in is ip lease and more specifically, the ip lease UUID. Look for it in the output.

:id: 2
:uuid: if-inst2
:mode: vif
- :id: 2
  :uuid: ml-sa4dusgn
  :interface_id: 2
  - &1
    :id: 2
    :uuid: il-36cl1ou4 # <== This is what we're looking for.
    :interface_id: 2

In this example it's il-36cl1ou4 but it will be something else on your environment. These UUIDs are randomly generated by OpenVNet when a new resource is created.

Now run the following two commands, deleting the old ip lease and creating a new one on the new network. Replace il-36cl1ou4 with the correct ip lease UUID for your environment.

vnctl ip-leases del il-36cl1ou4
vnctl ip-leases add --interface-uuid if-inst2 --network-uuid nw-test2 --ipv4-address

That's it. The inst2 interface has now moved to the new network we created.


Log into inst2 and have it perform a new DHCP request.

lxc-console -n inst2
service network restart

If everything went well, inst2 should now have received IP address Now try pinging inst1.


If you did things right, ping should have now told you that inst1's network is unreachable. That's exactly right. Our LXC guests are now in two different networks and have no route to each other.

What's next?

Now that we have two different networks, let's try using a simulated router to connect them together.