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Re: [libvirt] Hyper-V driver API version support



2013/8/9 Daniel P. Berrange <berrange redhat com>:
> On Fri, Aug 09, 2013 at 06:08:38PM +0200, Matthias Bolte wrote:
>> 2013/8/9  <surface me is-a-linux-user org>:
>> >> On Fri, Aug 09, 2013 at 10:13:03AM +0200, surface me is-a-linux-user org
>> >> wrote:
>> >>>
>> >>> Hello
>> >>>
>> >>> The "version" function is not supported by the hyperv driver:
>> >>> $ virsh --connect=hyperv://hypervhost version
>> >>> Compiled against library: libvirt 1.1.1
>> >>> Using library: libvirt 1.1.1
>> >>> Using API: Hyper-V 1.1.1
>> >>> error: failed to get the hypervisor version
>> >>> error: this function is not supported by the connection driver:
>> >>> virConnectGetVersion
>> >>>
>> >>> But we need this funtion for the "external/libvirt" stonith plugin
>> >>> of clusterglue:
>> >>>
>> >>> $ cat /usr/lib/stonith/plugins/libvirt | more
>> >>> # get status of stonith device (*NOT* of the domain).
>> >>> # If we can retrieve some info from the hypervisor
>> >>> # the stonith device is OK.
>> >>> libvirt_status() {
>> >>>     out=$($VIRSH -c $hypervisor_uri version 2>&1)
>> >>>     if [ $? -eq 0 ]
>> >>>     then
>> >>>         out=`echo "$out" | tail -1`
>> >>>         ha_log.sh notice "$hypervisor_uri: $out"
>> >>>         return 0
>> >>>     fi
>> >>>
>> >>>     ha_log.sh err "Failed to get status for $hypervisor_uri"
>> >>>     ha_log.sh err "$out"
>> >>>     return 1
>> >>> }
>> >>>
>> >>> So, we can't implement libvirt stonith with hyperv support in our
>> >>> corosync/pacemaker cluster. Is it possible to implement the
>> >>> "version" function for hyperv into virConnectGetVersion? Or exist
>> >>> any workaround for this problem?
>> >>
>> >>
>> >> I'm sure its possible, but it needs someone with knowledge of the
>> >> Hyper-V apis to write a patch and there's only a couple of people
>> >> in libvirt comunity who can do that. Patches welcome from any able
>> >> person...
>> >>
>> >> Daniel
>> >
>> >
>> > Hi Daniel
>> >
>> > I don't know which api is used for the driver handling, maybe you mean this
>> > one here: http://msdn.microsoft.com/en-us/library/aa155227.aspx
>> >
>> > I tested the following command on our micro$oft server:
>> > PS C:\Users\administrator> gwmi -namespace "root\virtualization"
>> > Msvm_VirtualSystemManagementService
>> >
>> >
>> > __GENUS                 : 2
>> > __CLASS                 : Msvm_VirtualSystemManagementService
>> > __SUPERCLASS            : CIM_VirtualSystemManagementService
>> > __DYNASTY               : CIM_ManagedElement
>> > __RELPATH               :
>> > Msvm_VirtualSystemManagementService.CreationClassName="Msvm_VirtualSystemManagementService",N
>> >
>> > ame="vmms",SystemCreationClassName="Msvm_ComputerSystem",SystemName="VSRV1"
>> > __PROPERTY_COUNT        : 21
>> > __DERIVATION            : {CIM_VirtualSystemManagementService, CIM_Service,
>> > CIM_EnabledLogicalElement,
>> >                           CIM_LogicalElement...}
>> > __SERVER                : VSRV1
>> > __NAMESPACE             : root\virtualization
>> > __PATH                  :
>> > \\VSRV1\root\virtualization:Msvm_VirtualSystemManagementService.CreationClassName="Msvm_
>> >
>> > VirtualSystemManagementService",Name="vmms",SystemCreationClassName="Msvm_ComputerSystem",Sys
>> >                           temName="VSRV1"
>> > Caption                 : Hyper-V Virtual System Management Service
>> > CreationClassName       : Msvm_VirtualSystemManagementService
>> > Description             : Service for creating, manipulating, and managing
>> > virtual systems
>> > ElementName             : Hyper-V Virtual System Management Service
>> > EnabledDefault          : 2
>> > EnabledState            : 2
>> > HealthState             : 5
>> > InstallDate             : 20130717120539.000000-000
>> > Name                    : vmms
>> > OperationalStatus       : {2}
>> > OtherEnabledState       :
>> > PrimaryOwnerContact     :
>> > PrimaryOwnerName        :
>> > RequestedState          : 12
>> > Started                 : True
>> > StartMode               :
>> > Status                  : OK
>> > StatusDescriptions      : {The service is running normally}
>> > SystemCreationClassName : Msvm_ComputerSystem
>> > SystemName              : VSRV1
>> > TimeOfLastStateChange   : 20130801095437.000000-000
>> > PSComputerName          : VSRV1
>> >
>> > so I think we can query the state like this:
>> > PS C:\Users\administrator> gwmi -namespace "root\virtualization"
>> > Msvm_VirtualSystemManagementService | select Status
>> >
>> >
>> > Status
>> > ------
>> > OK
>> >
>> > It's not the version, but we need something to let libvirt stonith know,
>> > that the stonith device can connect to hyperv and the hyperv service is
>> > running..
>>
>> The Hyper-V driver in libvirt already checks if the host has the
>> Hyper-V role installed on connect. It does this by checking for the
>> existance of an Msvm_ComputerSystem object, if there is non then
>> "virsh connect" fails. This means if "virsh connect" succeeds then the
>> URI you specified points to an Hyper-V server. No need to abuse the
>> version command for such a check.
>>
>> If you think that it is useful to check that an
>> Msvm_VirtualSystemManagementService object exists on the host then
>> this could be done in addition to the existing checks.
>
> What they really want, per the first mail, is for
>
>   virConnectGetVersion
>
> to be implemented for hyper-v

I understood that :)

But he doesn't actually need the version information, as far as I
understood his problem. The point is to say hello to the Hyper-V
server to see if it waves back indicating that it's still alive.

My point is that a successful "virsh connect" already provides this
aliveness information. Also there is virConnectIsAlive that is meant
for this purpose, but it's not wired up directly as command in virsh.

If one really insists on having more communication with the Hyper-V
server then "virsh nodeinfo" can be used instead of the currently not
implemented "virsh version" command for Hyper-V.

If the version information is really necessary in this case then that
can be implemented, but IIRC I didn't implemented this yet, because I
hadn't figure out where in the WMI data the required version
information is to be found.

-- 
Matthias Bolte
http://photron.blogspot.com


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