ERROR unable to connect to '/var/run/libvirt/libvirt-sock': Connection refused

Please ensure all these steps are done first. We can then isolate the error more accurately. The 1st few steps are taken from HowtoForge Virtualization With KVM On A CentOS 5.2 Server



Step 1: Checking the Virtualisation Technology on AMD and Intel

Step 2: Install KVM and virtinst

# yum install  kvm kmod-kvm qemu libvirt python-virtinst

Step 3: Reboot the System

# shutdown -r now

Step 4: Check that the KVM kernel Module is loaded

# lsmod grep kvm

kvm_intel     50452      0
kvm           109264     1 kvm_intel

(If you use Intel VT CPU, you should see the above, if you are using AMD-V processor, you should see kvm_amd)

When installing KVM and its related components on CentOS 5.x , you might encounter the error when you type the command "# virt-install"

ERROR unable to connect to '/var/run/libvirt/libvirt-sock': Connection refused
Traceback (most recent call last):
   File "/usr/sbin/virt-install", line 889, in ?
      main()
   File "/usr/sbin/virt-install", line 628, in main
      conn = cli.getConnection(options.connect)
   File "/usr/lib/python2.4/site-packages/virtinst/cli.py", line 126, in getConnction
      conn = libvirt.open(connect)
   File "/usr/lib64/python2.4/site-packages/libvirt.py", line 159, in open
     if ret is None:raise libvirtError('virConnectOpen() failed')
libvirtError: unable to connect to '/var/run/libvirt/libvirt-sock': Connection refused

To solve this, edit /etc/libvirt/libvirtd.conf and

# vim /etc/libvirt/libvirtd.conf

uncommented out the listen_tls = 0 line

listen_tls = 0

Start the libvirtd Daemon

# service libvirtd start

You should able to eliminate the error