Arch Linux

gtarch

Member

Registered: 2022-10-14

Posts: 48

[SOLVED] virt manager Failed to create PTY: Permission denied

I'm trying to create a virtual machine with virt-manager on a laptop, but I'm getting the following error:

Unable to complete install: 'internal error: process exited while connecting to monitor: 2025-08-15T08:55:12.573414Z qemu-system-x86_64: -chardev pty,id=charserial0: Failed to create PTY: Permission denied'

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 71, in cb_wrapper
    callback(asyncjob, *args, **kwargs)
    ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/share/virt-manager/virtManager/createvm.py", line 2008, in _do_async_install
    installer.start_install(guest, meter=meter)
    ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
  File "/usr/share/virt-manager/virtinst/install/installer.py", line 726, in start_install
    domain = self._create_guest(
            guest, meter, initial_xml, final_xml,
            doboot, transient)
  File "/usr/share/virt-manager/virtinst/install/installer.py", line 667, in _create_guest
    domain = self.conn.createXML(initial_xml or final_xml, 0)
  File "/usr/lib/python3.13/site-packages/libvirt.py", line 4594, in createXML
    raise libvirtError('virDomainCreateXML() failed')
libvirt.libvirtError: internal error: process exited while connecting to monitor: 2025-08-15T08:55:12.573414Z qemu-system-x86_64: -chardev pty,id=charserial0: Failed to create PTY: Permission denied

I'm in the llbvirt and tty groups. The same configuration works on a number of other Arch machines. I have no idea what's going on here.

My virt-manager version is 5.0.0-1

Last edited by gtarch (2025-08-16 05:30:55)

cryptearth

Member

Registered: 2024-02-03

Posts: 2,009

Re: [SOLVED] virt manager Failed to create PTY: Permission denied

do you try to create a user vm or a system vm?
get you asked for root password on start of virt-manager?

gtarch

Member

Registered: 2022-10-14

Posts: 48

Re: [SOLVED] virt manager Failed to create PTY: Permission denied

I just choose "new virtual machine". There is no option for user or system one.
I'm not asked for a password when I start virt-manager.

tekstryder

Member

Registered: 2013-02-14

Posts: 504

Re: [SOLVED] virt manager Failed to create PTY: Permission denied

$ grep -E "^user|^group" /etc/libvirt/qemu.conf

cryptearth

Member

Registered: 2024-02-03

Posts: 2,009

Re: [SOLVED] virt manager Failed to create PTY: Permission denied

usually when I start virt-manager I get asked for root password and have a connection of qemu/kvm to qemu:///system
virt-manager also offers a qemu/kvm connection to qemu:///session which is called "qemu/kvm user-session" - but it also warns "this is not standard, network operations are limited"

tekstryder

Member

Registered: 2013-02-14

Posts: 504

Re: [SOLVED] virt manager Failed to create PTY: Permission denied

usually when I start virt-manager I get asked for root password

This is covered in the wiki:

• https://wiki.archlinux.org/title/Libvirt#Configuration

gtarch

Member

Registered: 2022-10-14

Posts: 48

Re: [SOLVED] virt manager Failed to create PTY: Permission denied

grep -E "^user|^group" /etc/libvirt/qemu.conf

This doesn't find anything.

tekstryder

Member

Registered: 2013-02-14

Posts: 504

Re: [SOLVED] virt manager Failed to create PTY: Permission denied

Do you specifically require the serial console?

This doesn't find anything.

Ensure that the user account attempting to create the VM has the required permissions.

E.g. edit the relevant section in /etc/libvirt/qemu.conf for the user:

user = "gtarch"
group = "gtarch"

gtarch

Member

Registered: 2022-10-14

Posts: 48

Re: [SOLVED] virt manager Failed to create PTY: Permission denied

Do you specifically require the serial console?

No, it's a default.

Ensure that the user account attempting to create the VM has the required permissions.

E.g. edit the relevant section in /etc/libvirt/qemu.conf for the user:

I modified the config file, but the problem remained.

I did try removing the console device and that does work, but I have to wonder why I have this problem only on this laptop.
Anyway I can create VMs now by removing the console device. Thank you for your help!

Edit: Actually I forgot to restart libvirtd after modifying the config. I did it now and the problem is solved. I still have to wonder why it appears only on this machine, but at least there is a solution now.

Last edited by gtarch (2025-08-16 05:46:36)

tekstryder

Member

Registered: 2013-02-14

Posts: 504

Re: [SOLVED] virt manager Failed to create PTY: Permission denied

Actually I forgot to restart libvirtd

I should have included this, oops.

On that note, perhaps consider switching to modular daemons and socket-activated services as well.

• https://libvirt.org/daemons.html#modular-driver-daemons

I did this within the past year, and went with a more minimal approach than the full qemu set suggested in the doc.

Last edited by tekstryder (2025-08-16 14:31:58)