PowerCli Relocate VM storage with VI35 / VI4

This post provides a script to help with storage vMotion – migrating a VMware virtual machine from one VMFS datastore to another with no downtime. It’s a great tool, but in VI35 at least it’s not exposed through the GUI or VC scheduled tasks, so I’ve written a script to perform a few checks and allow for very simplistic 'scheduling' (delay).

I’ve only tested this with VI3.5 and PowerCLI 1.0, but I have no reason to think this wouldn’t with with vSphere vCenter and VI 4.0 hosts.

There are a few caveats with storage vMotion (in VC 2.5/ESX 3.5) at least, you can’t:
- Move the storage of a VM that has a snapshot if the VM is powered on
- Move the storage of a VM that has a snapshot (in any power state) if the VM has disks in a different location than the config file.

Based on these caveats, if instructed the script will suspend a VM with snapshots in order to move the storage, then power the VM back on. Use this with caution, as this may cause an outage of your VMs.

#
# Description:
#   Relocate a virtual machine from one datastore to another.
#
# Limitations:
#  -
#
# Assumptions, this script works on the assumption that:
#   The caller provides credentials with permissions to perform the operations
#
# Arguments:
#  vmName, lowecase short name for the virtual machine, eg pibutepr03
#  dataStoreName, the new datastore to migrate the VM to
#  suspend, Whether or not to suspend a VM and move if the VM has snapshots (which prevent live storage vMotion vi VI35)
#  username, The username to connect with, default to the current username environment variable
#  password, The Password to use for the connection, not specifying a password will result in a prompt to enter a secure string
#  delay, The optional number of seconds to delay before starting the operation
#
#
# Usage:
#   PowerShell . .\RelocateVM.ps1 -vmName "vm01" -datastore 'ds02'
#   PowerShell . .\RelocateVM.ps1 -vmName "vm01" -datastore 'ds02' -suspend yes -username domain\user
#
# Changes:
#  07/04/2009, Wayne Martin, Initial version
#

param (

    $vmName = "",
    $dataStoreName = "",
    $suspendIfRequired = $false,
    $username = $env:username,
    $password = "",
    $delay = 0
)


$ErrorActionPreference = "Continue"

 $invalidArgs = $false
if ($dataStoreName -eq "") { write-output "Please specify the datastore target for the VM, eg. ds02"; $invalidArgs = $true}
if ($vmName -eq "") { write-output "Please specify the virtual machine to move, eg vm01"; $invalidArgs = $true}
if ($account -eq "") { write-output "Please specify a user account to connect with, eg domain\user"; $invalidArgs = $true}

if ($invalidArgs) { write-output "Invalid Arguments, terminating"; exit}


Write-Output "Moving VM '$vmName' to the '$dataStoreName' datastore"

if ($delay -gt 0) {
    $hours = $delay / 60 /60
    Write-Output "Delaying $delay seconds before beginning ($hours hours)"
    Sleep -seconds $delay
}


if ($suspendIfRequired) {
    Write-Output "The virtual machine will be suspended if snapshots are preventing storage vMotion"
} else {
    Write-Output "If the virtual machine has snapshots and is powered on the storage vMotion will not work"
}

if ($password -eq "" -and !($pass)) {
    write-output "No password specified from the command-line"
    $pass = Read-Host "Password?" -assecurestring
}
$credential = new-object System.Management.Automation.PSCredential($username,$pass)    


$viServer = $null
$suspend = $false
$poweredOn = ""
$snapshot = $null
$hasSnapshot = $null

$viServer = Connect-VIServer -server $vcServerName -Credential $credential


if ($viServer) {
    Write-Output (Get-Date -format "dd/MM/yyyy HH:mm:ss")
    write-output ("Connected to server " + $viServer.Name + " on port " + $viServer.Port)

    $vm = get-vm -name $vmName
    if ($vm -and $vm -isnot [object[]]) {
        Write-Output ("Found " + $vm.Name)

        $hardDisks = $vm.hardDisks
        $vmSize = 0
        $vmSizeMB = 0
        foreach ($harddisk in $vm.hardDisks) {
            $vmSize += $hardDisk.CapacityKB
        }
        $vmSizeMB = $vmSize /1024

        $datastore = get-datastore -name $dataStoreName
        if ($datastore) {
            $freeSpace = $datastore.FreeSpaceMB
        
            if ($freeSpace -gt $vmSizeMB)
            {
                Write-Output "The datastore $datastoreName has $freeSpace MB available, the VM has disks totalling $vmSizeMB MB"
            
                switch ($vm.PowerState)
                {
                    ([VMware.VimAutomation.Types.PowerState]::PoweredOn)
                    {
                        Write-Output "The virtual machine is currently powered on"
                        $poweredOn = $true
                    }

                    ([VMware.VimAutomation.Types.PowerState]::PoweredOff)
                    {
                        Write-Output "The virtual machine is currently powered off"
                    }

                    ([VMware.VimAutomation.Types.PowerState]::Suspended)
                    {
                        Write-Output "The virtual machine is currently suspended"
                    }
            
                    default
                    {
                        write-output "Virtual machine power state unknown"
                    }
                }

                [object[]]$snapshot = get-snapshot -vm $vm
                if ($snapshot) 
                {
                    $hasSnapshot = $true
                    $numSnapshots = $snapshot.Count
                    Write-Output "$vmName currently has $numSnapshots snapshot(s)"
                    if ($poweredOn) {
                        if ($suspendIfRequired) {
                            Write-Output "$vmName is powered on and has a snapshot, and will be suspended during the move"
                            $suspend = $true
                        } else {
                            Write-Output "Error: $vmName is powered on and has a snapshot, but will not be suspended, process aborted"
                            $suspend = $false
                            exit 2
                        }
                    }
                } else {
                    $suspend = $false
                    $hasSnapshot = False
                    Write-Output "No snapshots currently found for $vmName"

                }

                if ($suspend) {
                    Write-Output "Suspending $vmName"
                    Suspend-VM -vm $vm -confirm:$false
                }

                Write-Output "Moving $vmName to $datastoreName"
                Move-VM -vm $vmName -datastore $datastoreName

                if ($suspend) {
                    Write-Output "Bringing $vmName out of suspension"
                    Start-VM -vm $vm -confirm:$false
                }
                Write-Output "$vmName migrated to $datastoreName"

            } else {
                Write-Output "The datastore only has $freeSpace MB available, but the VM has disks totalling $vmSizeMB MB"
            }
        } else {
            Write-Output "Error: datastore $datastoreName not found"
        }
    } else {
        if ($vm -is [object[]])
        {
            Write-Output "Multiple objects returned for $vmname, please specify a single VM"
        } else {
            write-output "VM Not found - $vmName"
        }
    }
} else {
    write-output "ERROR: VI server not found - $viServer"
}

Write-Output (Get-Date -format "dd/MM/yyyy HH:mm:ss")

Disconnect-VIServer -confirm:$false
exit 0

Wayne's World of IT (WWoIT), Copyright 2009 Wayne Martin.