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Libvirt does not work after installation
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.. contents::

TL;DR
=====

Most probably you want to start a virtqemud socket:

::

   # systemctl start virtqemud.socket

If you are unsure whether to do this, please read the rest of this document.

Symptom
=======

After installing libvirt or a virt tool that uses libvirt, commands do
not work when run as root:

::

   # virsh list
   error: failed to connect to the hypervisor
   error: Operation not supported: Cannot use direct socket mode if no URI is set.
   For more information see https://libvirt.org/kbase/failed_connection_after_install.html

Root cause
==========

Distribution guidelines and/or configurations may discourage or prohibit
starting services as part of a package installation.  And because libvirt cannot
know where you might want to connect it cannot start it on its own.

Solution
========

After installing libvirt you may need to start a particular libvirt daemon on
the local machine, set a (default) URI to connect to or, alternatively,
rebooting the machine might work.

If you are trying to connect to a remote libvirt daemon you need to specify a `connection URI <../uri.html>`__.

If you are trying to control a local hypervisor, then the solution depends on various factors. You should know:

- what hypervisor driver you want to connect to, whether it is ``virtqemud`` for QEMU, ``virtchd`` for Cloud Hypervisor, etc. and
- how to start a service or socket (in case of systemd) on you system.

Example of the most common solution, trying to use QEMU/KVM on Linux with systemd as an init system, is:

::

   # systemctl start virtqemud.socket

also provided on the top of the page.