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That Brazilian Guy
Asked: 2013-09-14 10:29:36 +0800 CST

virt-manager can't connect to libvirt

  • 772

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I'm running Ubuntu 12.04.2 32 bits.

The error doesn't show up if I start gksudo virt-manager.

  • libvirt-bin is installed.
  • I don't know how to check for the daemon.
  • I am a member of libvirtd.

Output of ps ax | grep libvirt:

9225 ? Sl 0:04 /usr/sbin/libvirtd -d
9302 ? S 0:00 /usr/sbin/dnsmasq -u libvirt-dnsmasq --strict-order --bind-interfaces --pid-file=/var/run/libvirt/network/default.pid --conf-file= --except-interface lo --listen-address 192.168.122.1 --dhcp-range 192.168.122.2,192.168.122.254 --dhcp-leasefile=/var/lib/libvirt/dnsmasq/default.leases --dhcp-lease-max=253 --dhcp-no-override`

Output of ls -l /var/run/libvirt/libvirt-sock:

srwxrwx--- 1 root libvirtd 0 Set 13 15:04 /var/run/libvirt/libvirt-sock

Output of getent group libvirtd:

 libvirtd:x:130:OTHERUSER,MYUSER

Detailed error message

Unable to connect to libvirt.   
Failed to connect socket to '/var/run/libvirt/libvirt-sock': Permission denied

Verify that:
 - The 'libvirt-bin' package is installed
 - The 'libvirtd' daemon has been started
 - You are member of the 'libvirtd' group

Libvirt URI is: qemu:///system

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/connection.py", line 1185, in _open_thread
    self.vmm = self._try_open()
  File "/usr/share/virt-manager/virtManager/connection.py", line 1167, in _try_open
    flags)
  File "/usr/lib/python2.7/dist-packages/libvirt.py", line 102, in openAuth
    if ret is None:raise libvirtError('virConnectOpenAuth() failed')
libvirtError: Failed to connect socket to '/var/run/libvirt/libvirt-sock': Permission denied
virtualization

19 Answers

  1. Rebooting the system where virt-manager is installed solved the issue.

    • 87

  2. After installing KVM, run this command then that error will not occur again.

    sudo virt-manager
    • 67
  3. Best Answer

    An alternative to reboot/logout is to run the following commands from a terminal:

    newgrp libvirt
virt-manager

    The newgrp command allows the user to join the libvirt group without logout, for processes that are started in the same shell after newgrp. Of course this only works if the libvirt installer put you in the libvirt group, which you can check with:

    getent group libvirt
    • 30

  4. For me, the error was caused because group membership changes don't apply without a logout-login (or reboot). I had just installed KVM and libvirt-bin. The installer automatically added my user to the libvirtd group, I had restarted the libvirt-bin service, but I was still getting the error.

    Don't change file permissions to 777. Don't just run everything as root or sudo to avoid understanding what's wrong.

    Simply logging out and back in resolved the problem by applying my new group membership.

    Assuming you just installed libvirt-bin and already confirmed that your current user is a member of the libvirtd group as the error message suggests, you will need to log out and back in for the new group membership to apply.

    I hope this helps someone.

    • 16

  5. I'm managing both Qemu and Virtualbox on my Ubuntu 14.02 machine, and after installing Virtualbox libvirt-bin failed to autostart. So check if libvirt-bin is running:

    ps faux | grep libvirt-bin

    if you don't see it in ps output - start in manually, then run virt-manager:

    sudo service libvirt-bin start

    • 5

  6. On Ubuntu 16.04.3 LTS 

    systemctl start virtlogd.socket

    was the only answer. The socket has its own daemon. That's unusual.

    • 5

  7. After installing all of the packages stated by the op, you can log out then log back in. Anything that add you to user groups you need to log out and back in to be added to the new groups. It is a minor inconvenience, less of one than rebooting.

    This was flagged as not complete however this goes as a general rule for adding your user to a group. A relog is needed, that was the missing part that I did not see here.

    • 2

  8. Logged in user has to be added to libvirt usergroup

    sudo usermod -a -G libvirt $USER
    • 2

  9. The user in libvirt group can run virt-manager and virsh without sudo.

    $ sudo gpasswd libvirt -a <username> 
$ cat <<EOF | tee -a ~/.profile
export VIRSH_DEFAULT_CONNECT_URI=qemu:///system 
EOF 
$ sudo reboot
    • 2

  10. For me the case was that when using service libvirt-bin status it showed that everything was just running fine though I could not connect like:

        ● libvirt-bin.service - Virtualization daemon
       Loaded: loaded (/lib/systemd/system/libvirt-bin.service; enabled; vendor preset: enabled)
       Active: active (running) since Do 2016-09-22 13:22:16 CEST; 6min ago
[...]

    In /var/run/libvirt/ there should be these two files:

    srwxrwxrwx  1 root libvirtd    0 Sep 22 13:22 libvirt-sock=
srwxrwxrwx  1 root libvirtd    0 Sep 22 13:22 libvirt-sock-ro=

    If the sockets are not showing, use service libvirt-bin stop; service libvirt-bin start to completely restart the process. Using service libvirt-bin restart is not sufficient and will not re-create the socket.

    The libvirt-bin service can safely be stopped and will not poweroff the guests.

    • 2