Shared Nothing Live Migration Between Clusters

Q: How can I perform a shared nothing live migration from one cluster to another cluster?

A: Shared nothing live migration allows the migration of a virtual machine (VM), including its storage, memory, and device state, between Hyper-V hosts without any downtime. A logical extension is the desire to perform a shared nothing live migration between Hyper-V clusters (when you don't want to use a cluster migration). However, you can't use shared nothing live migration to migrate between clusters directly. Instead, you need to do the following:

There's no downtime for any of these actions, because VMs can be added and removed from clusters without incurring downtime. I wrote a script that uses a basic flow to perform this action, as follows:

The complete script follows. Note that you need to run the script on a node in the source cluster. In addition, you might want to change the storage location that's used to store the VM on the target from the C:ClusterStorageVolume1 target that I hard-coded into the script. Also, make sure the Hyper-V Module for Windows PowerShell and the Failover Cluster Module for Windows PowerShell are installed on the host running the script. This script performs no error checking; it's a very basic script, so if you intend to use it in a major way you should probably add some error checking. My goal here is simply to show the required steps.

#Migrates virtual machines between clusters#Copyright 2014 John Savill##Assumes virtual switch with same name exists on target##Need to enable CredSSP to solve the double-hop problem associated with cluster commands#http://blogs.msdn.com/b/clustering/archive/2009/06/25/9803001.aspx documents the double-hop problem related to clustering remote commands#On the target server must have run Enable-WSManCredSSP Server#Lets get startedWrite-Host 'Please enter credential to be used for remote cluster execution'$CustomCred = Get-Credential #Get credentials to use with CredSSP on the remote clusterWrite-Host 'Ensure the target Server has been configured to accept CredSSP by running command Enable-ESManCredSSP Server on the server'$DestinationHost = Read-Host 'Enter the target host that will be used for all migrations >'Enable-WSManCredSSP Client -DelegateComputer $DestinationHost -Force$VMName = Read-Host 'Enter VM name to move >'while ($VMName -ne 'Q'){    #Show the cluster resources. Cannot use the $VMName as the cluster group as may not match, for example SCVMM names the cluster group differently    #Get-ClusterGroup -Name $VMName | Get-ClusterResource    $ClusterGroups = Get-ClusterGroup | ? {($_.GroupType -eq 'VirtualMachine') -and ($_.State -eq 'Online')}     foreach ($ClusterGroup in $ClusterGroups)    {        $TempVM = $ClusterGroup | Get-VM         if ($TempVM.Name.ToUpper() -eq $VMName.ToUpper())        {            $FinalClusterGroup = $ClusterGroup        }    }    $FinalClusterGroup | Get-ClusterResource    $ClusterGroupName = $FinalClusterGroup.Name    #Store the host the VM is currently active on if wanted to take the approach of NOT moving it to local node but means requires Constrained Delegation configured    $NodeName = Get-ClusterGroup -Name $ClusterGroupName | Get-ClusterResource | Where-Object {$_.ResourceType -eq "Virtual Machine"} | Select-Object OwnerNode    $CurrentNodeName = $NodeName.OwnerNode.Name    #View the VM    Get-VM -Name $VMName -ComputerName $CurrentNodeName    #Move the VM to the current host    $LocalNodeName = $env:COMPUTERNAME    if ($CurrentNodeName.ToUpper() -ne $LocalNodeName.ToUpper())    {        Write-Host 'Moving VM from '$CurrentNodeName' to current node'        Move-ClusterVirtualMachineRole -Name $ClusterGroupName -Node $LocalNodeName -MigrationType Live    }    #Remove the cluster resources and group which does not stop or remove the actual VM on the host    Write-Host 'Removing cluster group for VM'    Remove-ClusterGroup -Name $ClusterGroupName -RemoveResources -Force    #Sleep to avoid lock from removing cluster resources (not typically required)    Start-Sleep -Seconds 10    #Have to shutdown as different processor type (Intel to AMD in my case but normally would not need to stop the VM) or if different versions    #and processor compatibility not enabled    Stop-Vm -Name $VMName #This will wait until the VM has stopped    Start-Sleep -Seconds 10    #Now migrate it from this node so don't need -ComputerName $LocalNodeName    Write-Host 'Moving VM to target node'    Move-VM -Name $VMName -DestinationHost $DestinationHost -DestinationStoragePath C:ClusterStorageVolume1$VMName    $ScriptBlockContent = {        param ($VMName)        Add-ClusterVirtualMachineRole -VirtualMachine $VMName -Name $VMName }    #Now add as resource on the target cluster    Write-Host 'Making VM a cluster object on target'    Invoke-Command -ComputerName $DestinationHost -ScriptBlock $ScriptBlockContent -ArgumentList $VMName -Authentication Credssp -Credential $CustomCred    #Could automatically start the VM here if you wanted but I don't in this example    #Get next name    $VMName = Read-Host 'Enter VM name to move (Q to quit)>'    $VMName = $VMName.ToString()}

The following is an example execution moving a single VM.

PS C:> .MigrateBetweenClusters.ps1cfg         : http://schemas.microsoft.com/wbem/wsman/1/config/client/authlang        : en-USBasic       : trueDigest      : trueKerberos    : trueNegotiate   : trueCertificate : trueCredSSP     : truePlease enter credential to be used for remote cluster executionEnsure the target Server has been configured to accept CredSSP by running command Enable-ESManCredSSP Server on the serverEnter the target host that will be used for all migrations >: savaushv10Enter VM name to move >: Test - DC01Name         : SCVMM DC01 (1)State        : OnlineOwnerGroup   : SCVMM DC01 Resources (1)ResourceType : Virtual MachineName         : SCVMM DC01 Configuration (1)State        : OnlineOwnerGroup   : SCVMM DC01 Resources (1)ResourceType : Virtual Machine ConfigurationName             : Test - DC01State            : RunningCpuUsage         : 0MemoryAssigned   : 883949568MemoryDemand     : 724566016MemoryStatus     : OKUptime           : 81.20:38:09Status           : Operating normallyReplicationState : DisabledMoving VM from  savdalhv11 to current nodeName      : SCVMM DC01 Resources (1)OwnerNode : savdalhv10State     : OnlineRemoving cluster group for VMMoving VM to target nodeMaking VM a cluster object on targetName           : Test - DC01OwnerNode      : savaushv10State          : OfflinePSComputerName : savaushv10Enter VM name to move (Q to quit)>: Q