Re: [libvirt-users] About the change of a VM's vcpu count in runtime?
On 06/01/2013 03:16 PM, Dennis Chen wrote:
On 05/29/2013 04:28 AM, Eric Blake wrote:
> On 05/28/2013 02:24 PM, Eric Blake wrote:
>
>>> So the question is: is there any method I can't find yet to change the
>>> vcpu count of a running vm dynamically?
>> Wait for newer qemu and libvirt, or else pitch in and help write
>> patches.
> You might not have to wait that long - if you could help test these
> patches, it would be appreciated:
>
> https://www.redhat.com/archives/libvir-list/2013-May/msg01857.html
>
Hi,
After apply the patch, I've made a test. The testing environment as:
virsh # version
Compiled against library: libvirt 1.0.5
Using library: libvirt 1.0.5
Using API: QEMU 1.0.5
Running hypervisor: QEMU 1.5.0
The xml piece of the vm domain:
<channel type='unix'>
<source mode='bind'
path='/var/lib/libvirt/qemu/f16x86_64.agent'/>
<target type='virtio' name='org.qemu.guest_agent.0'/>
</channel>
the network connection between the vm and host is ok.
Also I installed the qemu-guest-agent in the guest os:
[root@localhost ~]#rpm -qa | grep qemu-guest
qemu-guest-agent-0.12.1.2-2.355.el6.i686
An error happened when I try to offline a guest vcpu in virsh:
virsh # setguestvcpu 8 1 --offline
error: Guest agent is not responding: Guest agent not available for now
Is there some step I missed before I invoke the 'setguestvcpu' command
in virsh or I need to write a program to hot-plug/unplug the vcpu with
the help of the new API introduced by this patch? Thanks!
BRs,
Dennis
update after investigation, I need to start up the 'qemu-guest-agent'
daemon in the guest
(https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Lin...):
[root@localhost ~]#qemu-ga
After that, I tried the command again:
virsh # setguestvcpu 8 1 --offline
error: internal error unable to execute QEMU agent command
'guest-set-vcpus': The command guest-set-vcpus has not been found
I think the communication between monitor and guest is ok, because below
command is OK:
virsh # shutdown 8 --mode agent
Domain 8 is being shutdown
VM shutdown after this command. Also, I double checked the
src/qemu/qemu_agent.c, and I can find the 2 functions:
qemuAgentGetVCPUs() and qemuAgentSetVCPUs()
Another,
virsh # qemu-agent-command 9
'{"execute":"cpu-add","arguments":{"id":2}}'
{"error":{"class":"CommandNotFound","desc":"The
command cpu-add has not
been found","data":{"name":"cpu-add"}}}
Seems the guest agent can't find vcpu hot-plug/unplug command, the qemu
I am using is 1.5.0, does it need some patches to handle this or
something I still missed?
BRs,
Dennis