3:37 p.m.
Greetings,
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)?
*2) *I am interested in identifying in particular other statistics of
migration like :
*Number of iterations in Pre Copy*, *Memory transferred in each iteration*
etc.
I was going through the API and found* virDomainJobInfo
<http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainJobInfo> and
virDomainGetJobStats
<http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainGetJobStats>
*functions.But
how to use them is not very clear. Can anyone point me to right place to
achieve this objective?
Thanks in advance.
And sorry if that was too silly to ask.
Anubhav
4:18 p.m.
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_C...
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=935...
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/eve...
for an example.
Jirka
1:57 a.m.
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(a)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
8:06 a.m.
New subject: [libvirt-users] [libvirt] Regarding Migration Statistics
On Tue, Jan 10, 2017 at 08:07:13PM +0530, Anubhav Guleria wrote:
Greetings,
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)?
Libvirt provides this information, I believe in virDomainGetJobStats().
If you call this function with flags |= VIR_DOMAIN_JOB_STATS_COMPLETED,
it will return various information on a recently completed job
(e.g. migration).
You can also register a callback for VIR_DOMAIN_EVENT_ID_JOB_COMPLETED
event, which will tell you all that right when the migration is completed.
*2) *I am interested in identifying in particular other statistics of
migration like :
*Number of iterations in Pre Copy*, *Memory transferred in each iteration*
etc.
I was going through the API and found* virDomainJobInfo
<http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainJobInfo> and
virDomainGetJobStats
<http://libvirt.org/html/libvirt-libvirt-domain.html#virDomainGetJobStats>
*functions.But
how to use them is not very clear. Can anyone point me to right place to
achieve this objective?
int type = -1, nparams = 0;
virTypedParameterPtr params = NULL;
virDomainGetJobStats(domain, &type, ¶ms, &nparams,
VIR_DOMAIN_JOB_STATS_COMPLETED)
This should be enough ^^. Since migration should be a job on bothe
source and destination, it may return different data, I'm not too sure
about that. You'll have to try that out or hope that someone else will
answer as well, sorry.
Thanks in advance.
And sorry if that was too silly to ask.
Anubhav
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3 comments
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participants (3)
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Anubhav Guleria -
Jiri Denemark -
Martin Kletzander