Monday, July 27, 2009

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. 

Wednesday, July 1, 2009

PowerShell - vSphere VMKernel NIC MTU

I came across a problem with VI4 (vSphere) on ESXi, where I was unable to create a vmkernel NIC for iSCSI with the vicfg-vmknic.pl script to set a custom MTU of 9000. This post provides a method using the GUI/perl script, and a PowerShell vSphere PowerCLI script to modify an existing VMKernel NIC.

It seems there is a bug in the perl script doesn't allow you to create a VMKernel NIC, however it does work if you create one through the GUI, and then use the script to delete and re-create the virtual NIC.

This was using a standalone ESXi server with a normal vSwitch - it wasn't managed by VC and it wasn't a DVS.

The GUI/PL script method:
  1. Create a VMKernel NIC in an existing vSwitch through the VI Client, with a port group called iSCSI1 in this example.
  2. Using the CLI, run the following commands, the first to delete the existing NIC, and then another to re-create the same NIC, but with an increased MTU:
    vicfg-vmknic.pl -d iSCSI1
    vicfg-vmknic.pl -a -i x.x.x.x -n x.x.x.x -m 9000 iSCSI1
  3. Run 'vicfg-vmknic.pl –l' to list the VMK NICs, which should show the adjusted MTU

I wasn't particularly happy with this method, so I looked at using the vSphere PowerCLI to set the MTU. For whatever reason, VMware chose not to expose the MTU property, which leaves only the SDK.

Luckily the PowerCLI makes it much easier to use the .Net SDK than previously possible with the Get-View cmdlet, so the script below is a combination of standard PowerCLI with a hook into the vNIC collection and the UpdateVirtualNic method to change a virtual NIC spec.


param (

    $MTU = 9000, 
    $nicName = vmk1, 
    $vcServer = "vcServer", 
    $vmServerName = "esx01"
)

#
#
# Description:
#  Update the MTU of a vmkernel NIC used for iSCSI
#
# Limitations:
#  DVS untested
#
# Assumptions, this script works on the assumption that:
#  The caller provides credentials with permissions to change the specified NIC
#
# Arguments:
#  MTU, The new MTU size, eg. 9000
#  nicName, The vmkernel NIC, eg. vmk1.  Note that this differs from the port group (eg. iSCSI1, with a NIC name of vmk1)
#  vcServer, the VC instance to connect to, eg. vcServer
#  vmServerName, The server name controlled by the VC instance (or direct), eg. esx01
#
# Usage:
#  PowerShell . .\UpdateVMKMTU.ps1 -MTU 9000 -nicName 'vmk1' -vcServer 'vcServer' -vmServerName 'esx01'
#
# References:
#  http://www.vmware.com/support/developer/vc-sdk/visdk400pubs/ReferenceGuide/vim.host.VirtualNic.Specification.html
#
# Changes:
#  26/06/2009, Wayne Martin, initial version

#$ErrorActionPreference = "Continue"


Connect-VIServer -server $vcServer        # connect to VC
$hostSystem = get-view -ViewType HostSystem -Filter @{"Name" = $vmServerName}   # Find the .Net view of the specified host
$hostConfigManager = $hostSystem.get_ConfigManager()      # Get the config manager
$hostNetworkSystem = $hostConfigManager.get_NetworkSystem()     # Find the MOR of the host network system
$netSystem = Get-View $hostNetworkSystem       # Get the object from the reference for the update method later

$hostconfig = $hostSystem.Config        # Get the current host config
$hostNetwork = $hostconfig.Network        # Get the current network host config
$hostvNIC = $hostNetwork.vNic         # Get the virtual NICs

$nicBeingUpdated = $null
foreach ($hostVirtualNIC in $hostvNIC) {       # For each virtual NIC
    if ($hostVirtualNIC.Device -eq $nicName) {        # Is this the device specified?
        $nicBeingUpdated = $hostVirtualNIC       # Yes, copy the object
    }
}

if ($nicBeingUpdated) {          # Was something found?
    $nicSpec = $nicBeingUpdated.Spec        # Yes, get the current spec
    $currentMTU = $nicSpec.MTU         # Get the current MTU from the spec

    if ($currentMTU -ne $MTU) {         # Is the MTU different?
        $nicSpec.set_Mtu($MTU)         # Yes, update the MTU on the copy of the spec of the existing NIC
        $netSystem.UpdateVirtualNic($nicName, $nicSpec)             # Call the update method from the netsystem, to update the NIC with the modified device spec

        write-output "MTU for $nicName updated from $currentMTU to $MTU"
        (get-vmhostnetwork).VirtualNic        # Output updated information
    } else {
        write-output "MTU for $nicName already set to $MTU, no changes made"
    }

} else {

    write-output "NIC $nicName not found, no changes made"

}


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