Autostart a Domain / VM Command

There are various ways to start virtual machines at at boot time. This means you don't have to type virsh start vmName command. This can be done by marking a vm as autostart. To configure a domain to be automatically started at boot. It will create an softlink at /etc/libvirt/qemu/autostart/. So if your VM name is debianlenny1, your config file name should be /etc/libvirt/qemu/debianlenny1.xml and the softlink should be created at /etc/libvirt/qemu/autostart//debianlenny1.xml

Autostart a Domain / VM Command

virsh autostart vmName
virsh autostart debianlenny1

Sample outputs:

Domain debianlenny1 marked as autostarted

Also, make sure /etc/init.d/libvirtd service is stared on boot:
chkconfig libvirtd on

Reference:  

LIBVRT virtualization API

The Virtualization API

libvirt is:

• A toolkit to interact with the virtualization capabilities of recent versions of Linux (and other OSes).
• Free software available under the GNU Lesser General Public License.
• A long term stable C API
• A set of bindings for common languages
• A CIM provider for the DMTF virtualization schema
• A QMF agent for the AMQP/QPid messaging system