[libvirt-users] Regarding Migration Statistics

[Anubhav Guleria]

Actually my setup is like this:

I have one controller host that do this migration between other two nodes
say A and B. Now where should this virDomainGetJobStats method should be
invoked from ?

If at present VM is migrated from A to B then should B call this method?

It's not clear.



"CODENAME FREAK -47"

On Tue, Jan 10, 2017 at 8:48 PM, Jiri Denemark <jdenemar at redhat.com> wrote:

> Please, do not post to several libvirt lists at once.
>
> > I am writing a code using libvirt API to migrate VM between two physical
> > hosts *(QEMU/KVM) , *say some *n *number of times.
> >
> > *1)* I am using right now* virDomainPtr virDomainMigrate (.......) *and
> to
> > calculate the total migration time I am using something like this:
> >
> > *clock_gettime(CLOCK_MONOTONIC_RAW,&begin);  *
> >  *migrate*(domainToMigrate,nodeToMigrate);
> >
> > *clock_gettime(CLOCK_MONOTONIC_RAW,&end);*
> >
> > *Total Migration Time = end.tv_sec-begin.tv_sec*
> >
> > Is this correct way to calculate total migration time. And is there some
> > way to calculate the downtime (not how to set it)?
>
> Well, just call virDomainGetJobStats and you will get both total time
> and downtime and many more.
>
> > virDomainGetJobStats
> > <http://libvirt.org/html/libvirt-libvirt-domain.html#
> virDomainGetJobStats>
>
> Yes, this is the right API to get all the statistics you want. It
> returns a list of (key, type, value) entires in params. The keys are
> VIR_DOMAIN_JOB_* (see
> http://libvirt.org/html/libvirt-libvirt-domain.html#
> VIR_DOMAIN_JOB_AUTO_CONVERGE_THROTTLE
> and a lot of other VIR_DOMAIN_JOB_* macros following this one for
> details). You can look at
> http://libvirt.org/git/?p=libvirt.git;a=blob;f=tools/virsh-domain.c;h=
> 93587e8bc7c79cbb66b6ee107472dfec5f320dab;hb=HEAD
>
> In short, just call
>
>     virTypedParamsGetULLong(params, nparams, VIR_DOMAIN_JOB_DOWNTIME,
>                             &value)
>
> to fetch downtime from params into value if it was present there (check
> return value of the API). The exact API to call is different for each
> type, although all migration statistics are unsigned long long so this
> one is all you need.
>
> BTW, you can call virDomainGetJobStats anytime while migration is
> running to monitor its progress. To check statistics of a completed
> migration it's easier to just register a callback for
> VIR_DOMAIN_EVENT_ID_JOB_COMPLETED event. See
> http://libvirt.org/git/?p=libvirt.git;a=blob;f=examples/
> object-events/event-test.c;h=55c004f93f40de628ae76221bb8ef9
> a13b2acb3d;hb=HEAD#l940
> for an example.
>
> Jirka
>
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