Hi, everyone I'm writing a application using libvirt and need to query guest os's virtual network interface usage, like bytes read or written through a given interface. I know int virDomainInterfaceStats(virDomainPtr dom, const char * path, virDomainInterfaceStatsPtr stats, size_t size) is designed for my purpose but I 'm not sure how I determine the second parameter path. I'm now think of determining the virtual interface by parsing the domain's xml configure file. But I don't find that libvirt supply such functions, that means, I have to resort to other library lik libxml?

On Fri, Apr 06, 2012 at 03:24:25PM +0800, Zhihua Che wrote: > Hi, everyone > > I'm writing a application using libvirt and need to query guest > os's virtual network interface usage, like bytes read or written > through a given interface. I know int > virDomainInterfaceStats(virDomainPtr dom, const char * path, > virDomainInterfaceStatsPtr stats, size_t size) is designed for my > purpose but I 'm not sure how I determine the second parameter path. > I'm now think of determining the virtual interface by parsing the > domain's xml configure file. > But I don't find that libvirt supply such functions, that means, I > have to resort to other library lik libxml? I would also really like to see such an API/APIs in the basic libvirt API.

I compile and install the libvirt-glib and I find its doc a little lean. I mean it's really hard to get applicable info from it because it just lists a list of functions without introducing any concepts first. I find the doc in share/gtk-doc directory. Do I miss anything? Is there any sample code or introduction to its concepts?

BTW, Does libvirt supply any function which can return the process identifier of the domain?

On Wed, Apr 11, 2012 at 12:01:55PM +0100, Daniel P. Berrange wrote: > On Wed, Apr 11, 2012 at 06:41:34PM +0800, Zhihua Che wrote: > > BTW, Does libvirt supply any function which can return the process > > identifier of the domain? > > No, we don't consider the PID of the QEMU process to be part of the > public API, since that is a hypervisor specific implementation detail. > Why do you want to know that ?  Maybe there is some API you can use > to get do the same thing I agree with Dan that you're probably doing it for the wrong reasons and shouldn't need to know the PID.

Nevertheless, it's pretty simple to map a running domain name to a qemu PID, by parsing the '-name' parameter from the process list. eg the following works for simple names (no spaces, metachars etc): $ sudo virsh list --all  Id Name                 State ----------------------------------  2 builder-rhel6        running $ ps ax | grep '[-]name builder-rhel6' | awk '{print $1}' 2311 Rich.

I guess I miss another thing. I thought the domain xml config file was stored in etc/libvirt/qemu/ directory.

在 2012年4月18日 下午5:31，Richard W.M. Jones <rjones(a)redhat.com&gt; 写道： > On Wed, Apr 18, 2012 at 10:24:24AM +0800, Zhihua Che wrote: >>    I guess I miss another thing. I thought the domain xml config file >> was stored in etc/libvirt/qemu/ directory. > > libvirt manages the config files.  To edit them, DON'T edit them > directly, use 'virsh edit'. > > Rich. >

On Wed, Apr 18, 2012 at 06:09:35PM +0800, Zhihua Che wrote: > 在 2012年4月18日 下午5:47，Zhihua Che <zhihua.che(a)gmail.com&gt; 写道： > > 在 2012年4月18日 下午5:31，Richard W.M. Jones <rjones(a)redhat.com&gt; 写道： > >> On Wed, Apr 18, 2012 at 10:24:24AM +0800, Zhihua Che wrote: > >>>    I guess I miss another thing. I thought the domain xml config file > >>> was stored in etc/libvirt/qemu/ directory. > >> > >> libvirt manages the config files.  To edit them, DON'T edit them > >> directly, use 'virsh edit'. > >> > >> Rich. > >> > > Correction > >  I agree with you. But I wanna know where libvirt stores all the domains' >  config files. >  Image that if I uninstalled libvirt and reinstalled it, I wish I could >  manipulate all the previous domains. All the persistent configs are under /etc/libvirt When a guest is running, there is a second config stored in /var/run/libvirt

On Wed, Apr 18, 2012 at 06:48:56PM +0800, Zhihua Che wrote: > 在 2012年4月18日 下午6:13，Daniel P. Berrange <berrange(a)redhat.com&gt; 写道： > > On Wed, Apr 18, 2012 at 06:09:35PM +0800, Zhihua Che wrote: > >> 在 2012年4月18日 下午5:47，Zhihua Che <zhihua.che(a)gmail.com&gt; 写道： > >> > 在 2012年4月18日 下午5:31，Richard W.M. Jones <rjones(a)redhat.com&gt; 写道： > >> >> On Wed, Apr 18, 2012 at 10:24:24AM +0800, Zhihua Che wrote: > >> >>>    I guess I miss another thing. I thought the domain xml config file > >> >>> was stored in etc/libvirt/qemu/ directory. > >> >> > >> >> libvirt manages the config files.  To edit them, DON'T edit them > >> >> directly, use 'virsh edit'. > >> >> > >> >> Rich. > >> >> > >> > >> Correction > >> > >>  I agree with you. But I wanna know where libvirt stores all the domains' > >>  config files. > >>  Image that if I uninstalled libvirt and reinstalled it, I wish I could > >>  manipulate all the previous domains. > > > > All the persistent configs are under /etc/libvirt > > > > When a guest is running, there is a second config stored in /var/run/libvirt > > > > I thought so. But I removed config file uder working/etc/libvirt and > It sill worked. Libvirtd loads all the configs under /etc/libvirt into memory, so if you delete them, libvirtd will still know about them until you restart it. > By the way, I installed my libvirt under directory working. Of course > I searched the whole system and found no other config files. If you are runing libvirtd as non-root then it uses $HOME/.libvirt If you built a custom libvirtd from source and run it as root, then it'll use $sysconfdir/libvirt  (where $sysconfdir is the --sysconfdir value passed to the configure script)