[Libvirt-cim] Query regarding Xen_ComputerSystem.RequestStateChange() and Live migration

Thu Oct 8 13:46:36 UTC 2009

Thank you Kaitlin and Deepti,

The VM "liveVm" on shared storage is being reported on both the hosts (source and destination), here is what we receive through "Xen_HostedDepenency" association:

[root at RHEL54-host1 ~]# wbemcli ain -ac Xen_HostedDependency 'http://root:password@localhost:5988/root/virt:Xen_HostSystem.CreationClassName="Xen_HostSystem",Name="RHEL54-host1"'
RHEL54-host1/root/virt:Xen_ComputerSystem.CreationClassName="Xen_ComputerSystem",Name="liveVm"
RHEL54-host1/root/virt:Xen_ComputerSystem.CreationClassName="Xen_ComputerSystem",Name="Domain-0"

[root at RHEL54-host1 ~]# virsh list
 Id Name                 State
----------------------------------
  0 Domain-0             running

[root at RHEL54-host2 ~]#  wbemcli ain -ac Xen_HostedDependency 'http://root:password@localhost:5988/root/virt:Xen_HostSystem.CreationClassName="Xen_HostSystem",Name="RHEL54-host2"'
RHEL54-host2/root/virt:Xen_ComputerSystem.CreationClassName="Xen_ComputerSystem",Name="localVm"
RHEL54-host2/root/virt:Xen_ComputerSystem.CreationClassName="Xen_ComputerSystem",Name="Domain-0"
RHEL54-host2/root/virt:Xen_ComputerSystem.CreationClassName="Xen_ComputerSystem",Name="liveVm"

[root at RHEL54-host2 ~]# virsh list
 Id Name                 State
----------------------------------
  0 Domain-0             running
  7 liveVm               idle

As you notice, virsh command is listing properly, but the association is not updated properly and results in both hosts.

On the RequestStateChange, we did not capture the message of stop failure. However, here is what we observe - we invoke the RequestStateChange method, it returns 0 - indicating success; But the VM will not start or stop due to insufficient resources. We assuming that RequestStatechange method to be synchronous call if it does not provide CIM_Job to track the status of start or stop. Generally starting a Windows VM take more than a minute.

Thanks again for your help,

Best Regards,
Madan 

-----Original Message-----
From: Deepti B Kalakeri [mailto:deeptik at linux.vnet.ibm.com] 
Sent: Thursday, October 08, 2009 1:13 PM
To: Velayudham, Madan Ganesh (STSD / ESS SW)
Cc: List for discussion and development of libvirt CIM; Kaitlin Rupert; Deepti B Kalakeri
Subject: Re: [Libvirt-cim] Query regarding Xen_ComputerSystem.RequestStateChange() and Live migration

Subba Rao, Sandeep M (STSD) wrote:
> Hi Kaitlin,
>
> Hope you are doing fine. 
>
> We need a clarification regarding the CIM_ConcereteJob support part of Xen_ComputerSystem.RequestStateChange() method to start or stop a Virtual Machine. After we invoke the method, we were expecting a return value of 4096 (Operation Scheduled) with the reference to Job to track the status.
>   
AFAIK, the method would not return 4096, it would return success or 
failure only.
> Instead we are noticing that the method returns 0 - indicating success, however the Virtual machine does not stop because of memory or other errors. 
>   
Can you elaborate on what operation you are doing here ?
What errors are you seeing ?
> Can you clarify whether this is a known issue in libvirt-CIM? Also recommend how to track the invoked job?
>   
Once the RqquestedStateChange() is successful you should be able to see 
the new state value in the Xen_ComputerSystem.EnabledState.
> The OS is an RHEL 5.4 and the libvirt and xen versions are as follows:
>
> [root at RHEL54 ~]# cat /etc/issue
> Red Hat Enterprise Linux Server release 5.4 Beta (Tikanga)
> Kernel \r on an \m
>
> [root at RHEL54 ~]# uname -a
> Linux RHEL54 2.6.18-160.el5xen #1 SMP Mon Jul 27 18:01:58 EDT 2009 i686 i686 i386 GNU/Linux
> [root at RHEL54 ~]# rpm -qa | grep libvirt
> libvirt-0.6.3-17.el5
> libvirt-cim-0.5.5-2.el5
> libvirt-python-0.6.3-17.el5
> [root at RHEL54 ~]# rpm -qa | grep xen
> kernel-xen-devel-2.6.18-160.el5
> kernel-xen-2.6.18-160.el5
> xen-3.0.3-92.el5
> xen-libs-3.0.3-92.el5
> [root at RHEL54 ~]# rpm -qa | grep sblim
> sblim-cmpi-base-1.5.5-34.el5
> [root at RHEL54 ~]#
>
> We also need clarification for live migration. We notice that Xen_ComputerSystem instance for the Virtual machine which is live migrated is being reported on the source and target host. Can you clarify us how to determine the actual host where the VM is associated? We were hoping that HostedDependency association will be helpful, but did not work.
>
>   
Once the live migration of the guest using libvirt-cim is successful you 
should not see any information of the VM on the host.
I dont think there is any means from which you can track information 
regarding the source from which the guest was migrated using libivrt-cim 
providers.
Xen_HostedDependency will give information of the VM's the particular 
Server hosts.
> Appreciate any help in this regard.
>
> Sandeep
>
> _______________________________________________
> Libvirt-cim mailing list
> Libvirt-cim at redhat.com
> https://www.redhat.com/mailman/listinfo/libvirt-cim
>   

-- 
Thanks and Regards,
Deepti B. Kalakeri
IBM Linux Technology Center
deeptik at linux.vnet.ibm.com