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@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