Why sys-usb shows as NetVM?

qubist · February 27, 2026, 11:24am

Hi,

Can anyone explain why sys-usb (a non-networked VM) shows as NetVM?

user@sys-usb:~ > qubesdb-read /qubes-vm-type
NetVM

rustybird · February 27, 2026, 11:43am

No other VM is configured as its netvm, and provides_network is enabled (for use with a USB network adapter). That’s what makes dom0 set /qubes-vm-type to NetVM:

github.com/QubesOS/qubes-core-admin

qubes/ext/r3compatibility.py

v4.3.43


      
          if isinstance(vm, qubes.vm.templatevm.TemplateVM):
              vmtype = "TemplateVM"
          elif vm.netvm is not None and vm.provides_network:
              vmtype = "ProxyVM"
          elif vm.netvm is None and vm.provides_network:
              vmtype = "NetVM"
          else:
              vmtype = "AppVM"
          vm.untrusted_qdb.write("/qubes-vm-type", vmtype)

Before Qubes OS R4, VM types were more rigid and /qubes-vm-type basically tells you what class of VM it would have been back then. It’s still used by startup scripts inside the VM to enable some services by default:

github.com/QubesOS/qubes-core-agent-linux

vm-systemd/qubes-sysinit.sh

v4.3.40


      
          DEFAULT_ENABLED_NETVM="network-manager qubes-network qubes-update-check qubes-updates-proxy meminfo-writer qubes-firewall software-rendering"
          DEFAULT_ENABLED_PROXYVM="qubes-network qubes-firewall qubes-update-check meminfo-writer software-rendering"
          DEFAULT_ENABLED_APPVM="qubes-update-check meminfo-writer tracker evolution-data-server software-rendering"
          DEFAULT_ENABLED_TEMPLATEVM="$DEFAULT_ENABLED_APPVM updates-proxy-setup software-rendering"

qubist · February 27, 2026, 12:24pm

Thanks @rustybird

I am confused by the fact that during installation I was asked whether I want sys-usb to be used as a NetVM and I explicitly refused. After your reply, I had a look and “Provides network” was checked. After unchecking it hows as AppVM.

I wonder if that means it is a bug.

What do you think?

rustybird · February 27, 2026, 12:39pm

I don’t remember such a question. Do you mean the installer’s “Use sys-net qube for both networking and USB devices” checkbox?

rustybird · February 27, 2026, 12:50pm

Enabling “Provides network” unconditionally for sys-usb is intentional:

github.com/QubesOS/qubes-issues

`sys-usb` has "Provides network" enabled by default

opened 02:53AM - 31 Jul 22 UTC

closed 11:08AM - 31 Jul 22 UTC

andrewdavidwong

R: duplicate R: not applicable P: default C: usb proxy diagnosed C: networking

[How to file a helpful issue](https://www.qubes-os.org/doc/issue-tracking/) #…## Qubes OS release Qubes OS 4.1.1 ### Brief summary It seems like a bug that `sys-usb` has `Provides network` enabled by default in the first place on systems with no networking devices in `sys-usb`. Related: #7298

qubist · February 27, 2026, 2:15pm

Do you mean the installer’s Use sys-net qube for both networking and USB devices checkbox?

Exactly.

Thanks for the link!

KitsuneNoBaka · February 27, 2026, 2:53pm

There is a bug in r4.2 that service vm feature is not persistent and to make qube be a service qube you need to enable provides network. That’s why that is in sys-audio guide.

Dunno about r4.3

qubist · February 27, 2026, 3:23pm

@KitsuneNoBaka

I unset the “Provides network” and after restarting the VM it is AppVM. I guess this means persistence.

KitsuneNoBaka · February 27, 2026, 3:36pm

In r4.2, if you set just qvm-features sys-audio servicevm 1 then after restart is not set and sys-audio is seen as normal appVM.
If you set provides network then after restart sys-audio is seen as serviceVM and feature servicevm is set.
That’s probably why in r4.2 sys-usb have provides network even if you opted that out.

As I said dunno about r4.3, so unset provides network and do qvm-features sys-usb servicevm 1 in dom0 and test if sys-usb will be still serviceVM after restart.

qubist · February 27, 2026, 5:07pm

@KitsuneNoBaka

I see no such feature of sys-usb in 4.3.0. I see it for sys-net and sys-firewall. I don’t know if it was there before unsetting “Provides network”.

What is the purpose of this feature?

KitsuneNoBaka · February 27, 2026, 8:49pm

To mark qube as service qube.

qubist · February 28, 2026, 7:10am

@KitsuneNoBaka

To mark qube as service qube.

What is a “service qube” and how is it different from a non-service qube. I might be missing something that I need to learn.

qubist · February 28, 2026, 7:35am

P.S. I am just wondering if the flag “service qube” has any other function besides how qubes are filtered in Qube Manager. Currently I am running a sys-usb qube that is not a “service qube” and I don’t see any issues.

parulin · February 28, 2026, 10:20am

https://dev.qubes-os.org/projects/core-admin-client/en/latest/manpages/qvm-service.html

Changes the qube icon to ServiceVM theme and moves the qube to SERVICE tab of Qubes

That is all I see…

qubist · February 28, 2026, 1:34pm

@parulin

Thanks.

So, it seems just another flag, similar to the “disposable template”, aimed to serve cosmetic purposes in the UI.

wafmtjwadllc · March 19, 2026, 10:28pm

This setting is enabled by default during installation to support users who may connect USB Wi-Fi or Ethernet adapters to sys-usb . This is not Bug.