Register a LUN full of VMs with PowerCLI

One of the great things about VMware vSphere is virtual machine encapsulation — a VM is simply a directory of files that can be easily copied around by administrators for a variety of purposes.  Most other platforms obfuscate virtual machines beyond recognition.

Recently, I was working on a project that required a large number of VMs that I had used previously but were no longer registered on a VMware ESXi host — they were just waiting patiently on a SAN LUN for their day to come.

Using the vSphere Client to connect the VMFS datastore to a host was a snap.  However, I was not enthusiastic about the several dozen clicks that would have been needed to bring them all back into the inventory for use, so I came up with a simple PowerCLI command to do all the work.

I was so pleased with the power of PowerCLI that I had to share…

Register all virtual machines on a datastore

Connect to vCenter Server with a PowerCLI session and adjust the obvious placeholders to suit your environment:

$esxhost= Get-VMHost myhost.example.com
dir 'vmstores:\myvCenterServer@443\DC1\CX4-02-LUN12\*\*.vmx' |
 % {New-VM -Host $esxhost -VMFilePath $_.DatastoreFullPath}

A few moments later, all the VMs are correctly registered and ready for action.

Build a local hosts file with PowerCLI

Another issue I encountered was the lack of DNS for guest operating systems at an offsite lab.  There was no way to connect to the various VMs by name, only IP address — not my favorite approach.  Since vSphere has information about guest networking, I quickly generated a list of IP addresses and VM names in a format suitable for pasting into my local hosts file:

Get-VM | sort-object -Property Name |
 Get-VMGuest | % {$_.ipaddress[0] + "`t" + $_.VMName}

PowerCLI to the rescue again.  What are your favorite PowerCLI one-liners?

Related posts:

1. Easy recovery from a full VMware ESX datastore
2. Using SCVMM to attach ISO images to VMware ESX VMs
3. PowerShell Prevents Datastore Emergencies
4. VM Encapsulation
5. vSphere Thin-Provisioned Disk Performance