Get-FileHash on vmdk file using PowerCLI

[Danielman111]

I need to calculate a hash on a vmdk file (around 50GB), I want to do this using PowerCLI, and In a remote way (the remote thing is critical).

The remote vmdk file is in the datastore (ESXi host)

I tried to map the disk the following way:

1. connect to the Vcenter using :

     Connect-VIServer

2. declared my variable:

     $ssds = Get-Datastore -Name "CCT_VMs_22"

     $dataStoreForSnapshots = "z"

3. and mapped the path:

     New-PSDrive -Location $ssDs -Name $dataStoreForSnapshots -PSProvider VimDatastore -Root "" -Scope "Local"

4.Then from the path of the vmdk location I tried:

     Get-FileHash <filepath> -Algorithm MD5

filepath: z:\ELK-Win8x64_tmp\ELK-Win8x64_tmp.vmdk

and get the follwing error:

Test-Path : File [CCT_VMs_22] server@443/ILHZ-Lab/CCT_VMs_22/ELK-Win8x64_tmp/ was not found

At

C:\windows\system32\windowspowershell\v1.0\Modules\Microsoft.PowerShell.Utility\Microsoft.PowerShell.Utility.psm1:80

char:20

+ ...              if(Test-Path -LiteralPath $filePath -PathType Container)

+                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    + CategoryInfo          : NotSpecified: (:) [Test-Path], FileNotFound

    + FullyQualifiedErrorId : VMware.VimAutomation.ViCore.Types.V1.ErrorHandling.FileNotFound,Microsoft.PowerShell.Com

   mands.TestPathCommand

Get-FileHash : The file

'\server@443\ILHZ-Lab\CCT_VMs_22\ELK-Win8x64_tmp\ELK-Win8x64_tmp.vmdk' cannot be read: Could

not find a part of the path

'C:\server@443\ILHZ-Lab\CCT_VMs_22\ELK-Win8x64_tmp\ELK-Win8x64_tmp.vmdk'.

At line:1 char:1

+ Get-FileHash z:\ELK-Win8x64_tmp\ELK-Win8x64_tmp.vmdk -Algorithm MD5

+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    + CategoryInfo          : ReadError: (\server...in8x64_tmp.vmdk:PSObject) [Write-Error], WriteErrorExcepti

   on

    + FullyQualifiedErrorId : FileReadError,Get-FileHash

any ideas how to get the following done?

[LucD]

I suspect tat the datastore provider doesn't implement all the features.

That could explain why the Test-Path seems to go back to the internal notation.

I'll have to some more testing to confirm that, and eventually find an alternative

[vXav]

I tried a Get-member on a vmx file item:

Get-Item 'vmstore:\DCname\DSname\VMfolder\VMname.vmx' | Get-Member

There is a method called GetHashCode : https://msdn.microsoft.com/en-us/library/system.object.gethashcode(v=vs.110).aspx

My test:

(Get-Item 'vmstore:\DCname\DSname\VMfolder\VMname.vmx').GetHashCode()

>> 66599629

Alter the .vmx by adding 1GB to the disk of the VM

(Get-Item 'vmstore:\DCname\DSname\VMfolder\VMname.vmx').GetHashCode()

>> 11991899

I did the test on a vmx because it's easy to alter but you get the idea.

I'm not saying it's the solution you're looking for but maybe a starting point.

[LucD]

The GetHashCode method gets the hash for the object, not the file.

It is mostly used to compare two objects.

[LucD]

As I suspected, the datastore provider has not implemented the functionality to "read" a file.

When you do for example (DS is the name I gave to the datastore drive)

Get-Content -Path "DS:/vm1/vm1.vmdk"

You get the error

But ESXi has a builtin command for calculating the md5 sum.

If you have SSH enabled, you can do something like this

$vmName = 'TestVM'

$vm = Get-VM -Name $vmName

$hd = Get-HardDisk -VM $vm | where{$_.Name -eq 'Hard disk 1'}

$dsName = $hd.Filename.Split(']')[0].TrimStart('[')

$user = 'root'

$pswd = 'P@ssW0rd!'

$plink = 'C:\PuTTY\plink.exe'

$plinkoptionsPre = " -pw $Pswd"

$plinkoptions = " -batch -pw $Pswd"

$cmd1 = "cd /vmfs/volumes/$($dsName)/$($vm.Name); md5sum $($hd.Filename.Split('/')[-1])"

$remoteCommand = '"' + $cmd1 + '"'

$command = $plink + " " + $plinkoptionsPre + " " + $User + "@" + $vm.VMHost + " " + $remoteCommand

Invoke-Expression -Command $command