9:40 p.m.
Hi,
I've more quries on libvirt apis:
1. Is there any API in libvirt that gives me the uptime of the
guets.
2. Can I know how many physical CPUs are dedicated to a VM or if
they are shared.
3. How do I know the logical cpu consumption of the guests( from
dom0 using libvirt obviously).
4. Can get the ip address of each of the guests with any of the
APIs
Thanks,
Vadiraj
11:35 p.m.
Katti, Vadiraj (STSD-Openview) wrote:
Hi,
I've more quries on libvirt apis:
1. Is there any API in libvirt that gives me the uptime of the
guets.
No there isn't, unfortunately. Best you can do is to tell how much CPU
time a guest has used.
I suspect this information is not available from the Xen hypervisor. If
it is, then we ought to expose it where possible.
2. Can I know how many physical CPUs are dedicated to a VM or if
they are shared.
Yes you can tell this by using the terribly complicated
'virDomainGetVcpus' function. Read the manual page _very_ carefully for
this one :-(
virt-top uses this function to display the % used and mapping of VCPUs
to PCPUs in real time, so you might find playing with virt-top and
looking at the code useful:
http://hg.et.redhat.com/virt/applications/virt-top--devel?f=e100f86fdf28;...
3. How do I know the logical cpu consumption of the guests( from
dom0 using libvirt obviously).
This is sort of possible. See this page for discussion and limitations
of the current API:
http://et.redhat.com/~rjones/virt-top/faq.html#pcpu
4. Can get the ip address of each of the guests with any of the
APIs
No. Guests can send out packets from their interface using any IP
address they want. By convention it's normally set up so that guests
get an IP address from a DHCP server, but that's only a convention, not
required. Imagine rephrasing the question as "Can I get the IP address
of each machine on my LAN?".
Rich.
--
Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/
Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod
Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in
England and Wales under Company Registration No. 03798903
11:44 p.m.
Richard W.M. Jones wrote:
Katti, Vadiraj (STSD-Openview) wrote:
> 4. Can get the ip address of each of the guests with any of the
> APIs
No. Guests can send out packets from their interface using any IP
address they want. By convention it's normally set up so that guests
get an IP address from a DHCP server, but that's only a convention, not
required. Imagine rephrasing the question as "Can I get the IP address
of each machine on my LAN?".
Actually, if I'd thought about that a bit more, I might have said: look
in your local ARP table, and compare the MAC addresses with the ones in
the libvirt domain XML.
It's still true to say that there isn't necessarily a fixed 1-1
relationship between guests' network cards and IP addresses.
Rich.
--
Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/
Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod
Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in
England and Wales under Company Registration No. 03798903
12:45 a.m.
On Thu, Dec 13, 2007 at 03:35:44PM +0000, Richard W.M. Jones wrote:
Katti, Vadiraj (STSD-Openview) wrote:
>Hi,
> I've more quries on libvirt apis:
> 1. Is there any API in libvirt that gives me the uptime of the
>guets.
No there isn't, unfortunately. Best you can do is to tell how much CPU
time a guest has used.
I suspect this information is not available from the Xen hypervisor. If
it is, then we ought to expose it where possible.
It is not available from the HV - the HV has no concept of real world
time.
> 2. Can I know how many physical CPUs are dedicated to a VM or
if
>they are shared.
Yes you can tell this by using the terribly complicated
'virDomainGetVcpus' function. Read the manual page _very_ carefully for
this one :-(
virt-top uses this function to display the % used and mapping of VCPUs
to PCPUs in real time, so you might find playing with virt-top and
looking at the code useful:
http://hg.et.redhat.com/virt/applications/virt-top--devel?f=e100f86fdf28;...
> 3. How do I know the logical cpu consumption of the guests( from
>dom0 using libvirt obviously).
This is sort of possible. See this page for discussion and limitations
of the current API:
http://et.redhat.com/~rjones/virt-top/faq.html#pcpu
> 4. Can get the ip address of each of the guests with any of the
>APIs
No. Guests can send out packets from their interface using any IP
address they want. By convention it's normally set up so that guests
get an IP address from a DHCP server, but that's only a convention, not
required. Imagine rephrasing the question as "Can I get the IP address
of each machine on my LAN?".
And guests can have multiple IP address. They can have IPv4 and IPv6
address. They can even have the same addresses under some scenarios
(clustering)
Dan.
--
|=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=|
|=- Perl modules: http://search.cpan.org/~danberr/ -=|
|=- Projects: http://freshmeat.net/~danielpb/ -=|
|=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|
7:54 p.m.
"Xm uptime" gives the uptime of all the domains running. So I believe
there should be a way to get it.
I'm trying to find what interface xm uses. Will update the group once I
get more insight.
-----Original Message-----
From: Richard W.M. Jones [mailto:rjones@redhat.com]
Sent: Thursday, December 13, 2007 9:06 PM
To: Katti, Vadiraj (STSD-Openview)
Cc: libvir-list(a)redhat.com
Subject: Re: [Libvir] More queries
Katti, Vadiraj (STSD-Openview) wrote:
Hi,
I've more quries on libvirt apis:
1. Is there any API in libvirt that gives me the uptime of the
guets.
No there isn't, unfortunately. Best you can do is to tell how much CPU
time a guest has used.
I suspect this information is not available from the Xen hypervisor. If
it is, then we ought to expose it where possible.
2. Can I know how many physical CPUs are dedicated to a VM or if
they
are shared.
Yes you can tell this by using the terribly complicated
'virDomainGetVcpus' function. Read the manual page _very_ carefully for
this one :-(
virt-top uses this function to display the % used and mapping of VCPUs
to PCPUs in real time, so you might find playing with virt-top and
looking at the code useful:
http://hg.et.redhat.com/virt/applications/virt-top--devel?f=e100f86fdf28
;file=virt-top/virt_top.ml
3. How do I know the logical cpu consumption of the guests( from
dom0
using libvirt obviously).
This is sort of possible. See this page for discussion and limitations
of the current API:
http://et.redhat.com/~rjones/virt-top/faq.html#pcpu
4. Can get the ip address of each of the guests with any of the
APIs
No. Guests can send out packets from their interface using any IP
address they want. By convention it's normally set up so that guests
get an IP address from a DHCP server, but that's only a convention, not
required. Imagine rephrasing the question as "Can I get the IP address
of each machine on my LAN?".
Rich.
--
Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/
Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod
Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in
England and Wales under Company Registration No. 03798903
8:16 p.m.
Katti, Vadiraj (STSD-Openview) wrote:
"Xm uptime" gives the uptime of all the domains running. So
I believe
there should be a way to get it.
I'm trying to find what interface xm uses. Will update the group once I
get more insight.
Indeed it does. Apparently xend returns a 'start_time' field for a
domain, which is the start time as a Unix time_t. 'xm uptime' just
prints out the current time minus this start time.
One problem seems to be that this is saved in the image across reboots,
so presumably it's fairly meaningless if the host machine was switched
off for a signficant length of time.
Rich.
--
Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/
Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod
Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in
England and Wales under Company Registration No. 03798903
6109
days inactive
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5 comments
3 participants
participants (3)
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Daniel P. Berrange -
Katti, Vadiraj (STSD-Openview) -
Richard W.M. Jones