Enabling VNC access to KVM hosts on node
By default VNC listens only on localhost or its own IP address, to make libvirt VNC listen on all interfaces edit the file /etc/libvirt/qemu.conf and set vnc_listen = "0.0.0.0".
$ grep ^vnc_listen /etc/libvirt/qemu.conf
vnc_listen = "0.0.0.0"
To enable VNC on the VM edit the XML file and append the below line before <devices> tag:
<graphics type='vnc' port='-1' autoport='yes' keymap='en-us'>
<listen type='address'/>
</graphics>$ virsh vncdisplay linux1
:0
VNC port starts from range 5900, here :0 indicates port 5900.

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