libvirt users - Mar 2014 - How to get guest's cpu and mem usage with Java APIs

Hi everybody,

I'm using libvirt java api bindings for my thesis. I would like to know if
there is a way to obtain live information about cpu and mem usage of a
domain.

Regards,

Enrico De Maio
Skype: enrico.de.maio
Mobile: +39 338 205 3397

On 03/10/2014 04:54 AM, Enrico De Maio wrote:
> Hi everybody,
> 
> I'm using libvirt java api bindings for my thesis. I would like to know
if
> there is a way to obtain live information about cpu and mem usage of a
> domain.
Are you asking the question from the host's perspective (how much
resources has the host given to the guest) or from the guest's
perspective (how much is the guest actively using, even if the host has
given it more)?  Libvirt already provides several API calls. such as the
ones used by 'virsh cpu-stats' and 'virsh dommemstat'; you may
have to
do some code reading to figure out what C calls the virsh code made in
order to find the same API under the Java bindings.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

I would like to know how much memory and cpu virtual machine are using so
yes guest's perspective. I'm building a web app that has to alert the
user
when the vm is going to be stressed and I would like to do this in terms of
mem and cpu usage.

Thanks in advance for your support,

Enrico De Maio


On Mon, Mar 10, 2014 at 7:16 PM, Eric Blake <eblake@redhat.com> wrote:
> On 03/10/2014 04:54 AM, Enrico De Maio wrote:
> > Hi everybody,
> >
> > I'm using libvirt java api bindings for my thesis. I would like to
know
> if
> > there is a way to obtain live information about cpu and mem usage of a
> > domain.
>
> Are you asking the question from the host's perspective (how much
> resources has the host given to the guest) or from the guest's
> perspective (how much is the guest actively using, even if the host has
> given it more)?  Libvirt already provides several API calls. such as the
> ones used by 'virsh cpu-stats' and 'virsh dommemstat'; you
may have to
> do some code reading to figure out what C calls the virsh code made in
> order to find the same API under the Java bindings.
>
> --
> Eric Blake   eblake redhat com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>
>

At Mon, 10 Mar 2014 21:38:21 +0100,
Enrico De Maio wrote:
> 
> I would like to know how much memory and cpu virtual machine are using so
> yes guest's perspective.
See Domain.memoryStats[1] for retrieving memory statistics about a
domain. AFAIK, the stats returned depend upon the guest OS and whether
you have some guest additions (ie. the balloon driver for qemu)
installed.

There's currently no way of retrieving the CPU stats of a domain from
Java. (patches welcome)

[1]:
http://libvirt.org/sources/java/javadoc/org/libvirt/Domain.html#memoryStats(int)
> I'm building a web app that has to alert the user when the vm is
> going to be stressed and I would like to do this in terms of mem and
> cpu usage.
> 
> Thanks in advance for your support,
> 
> Enrico De Maio
> 
> 
> On Mon, Mar 10, 2014 at 7:16 PM, Eric Blake <eblake@redhat.com>
wrote:
> 
> > On 03/10/2014 04:54 AM, Enrico De Maio wrote:
> > > Hi everybody,
> > >
> > > I'm using libvirt java api bindings for my thesis. I would
like to know
> > if
> > > there is a way to obtain live information about cpu and mem usage
of a
> > > domain.
> >
> > Are you asking the question from the host's perspective (how much
> > resources has the host given to the guest) or from the guest's
> > perspective (how much is the guest actively using, even if the host
has
> > given it more)?  Libvirt already provides several API calls. such as
the
> > ones used by 'virsh cpu-stats' and 'virsh dommemstat';
you may have to
> > do some code reading to figure out what C calls the virsh code made in
> > order to find the same API under the Java bindings.
> >
> > --
> > Eric Blake   eblake redhat com    +1-919-301-3266
> > Libvirt virtualization library http://libvirt.org
> >
> >
-- 
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