Re: [libvirt] Node devices?

On Wed, Feb 10, 2010 at 1:02 AM, Daniel P. Berrange <berrange(a)redhat.com&gt; wrote: > Mostly what Alex already said :-) > > The libvirt APIs are split into several functional areas > > - virDomain - guest management > - virInterface - host network interface configuration > - virStorage - storage manangement > - virNetwork - virtual networking > > The goal is that an app should be able to accomplish all its virtualization > management tasks without needing any other remote access to the host via > SSH or other systems. Many of the APIs for those areas I mention above > require knowledge of what physical devices are present on the machine. For > example, assigning a PCI or USB device to a guests requires that you know > what PCI / USB devices the host has. Setting up a storage pool requires > knowing what disks are available. Configuring network interfaces requires > knowing what NICs are available, etc. So 'virNodeDev' APIs provide the > missing link that lets you discover the information about a host that you > need in order to use the other APIs. Thanks, Daniel and Alex, that helps a lot. I'm still not clear about the purpose of the node device XML format, and the nodedev-create virsh command. What does it mean to "create a device" on a node, if the node device info is gathered via udev or hal from the actual hardware? Is this to fill in gaps in udev's or hal's knowledge of the hardware?