Configuring a Host-Only network adapter with Ubuntu running on a VM

November 21, 2023

For work I sometimes need to test or debug deployments on virtual machines. To do this I like to spin up a local vm in Virtualbox. Since I need to be able to ssh into it, it requires a host-only network adapter.

Whenever I provision a fresh machine of this kind, I have forgotten how to get the host-only adapter to work and it's hard to find the right instructions online since the process has changed so much during the various Ubuntu version.

So here it goes: How to set up a host-only adapter with Ubuntu 22.04 running in a Virtualbox:

Make sure the host-only adapter is connected to the machine. This is done in the settings of the VM in Virtualbox. Adapters can only be added or removed when the machine is down.
Logged into the VM run ip link show to list available network interfaces. Depending on what you configured there should be a number of devices listed. Most likely the loopback device, the NAT device and the host-only device, which should show as down. Now note the name of the host-only device
Open the netplan configuration at /etc/netplan/00-installer-config.yaml and add the host-only device like in the following example. In this case I'm assigning a static IP, but I think dhcp works too.

network:
  ethernets:
    enp0s3:
      dhcp4: true
    enp0s8: # This is the network device I identified earlier
      dhcp4: no
      addresses:
        - 192.168.56.104/24
  version: 2

Finally run netplan apply to apply the changes
Now you should see the interface as up when running ip a