In a recent blog post, I showed a simple method of outputting a list of hosts with their friendly names, as well as their MoRef (Managed Object Reference) names alongside eachother, enabling you to match up which host belongs to which MoRef. I wanted to take that a little further, with a function that is able to return the friendly name of a host’s MoRef that is input into the function. I have used this is a larger reporting script, where I can only get the MoRef of a host via it’s property within a cluster object. Basically, I look for any Failover hosts (admission control policy), which is an array, and the hosts are listed as indexed objects of this array. They are also only displayed as MoRef names, so at this point, instead of inserting the MoRef into my results, I insert the MoRef into this function, return the friendly name, and input this instead. Which allows the person reading the report to easily identify the host! $cluster.ExtensionData.Configuration.DasConfig.AdmissionControlPolicy.FailoverHosts <- In this example, $cluster is a particular cluster using the “specify a failover host” policy, and “FailoverHosts” is the array, with each object within containing a host MoRef. For example FailoverHosts[0].Value would be one instance, and may equate to “HostSystem-host-28” for example. So here is the function. It takes two mandatory parameters: -MoRef (the MoRef of the host in question of course), and -Cluster (the name of the Cluster to do the lookup in) – the function loops through each host in this cluster to look for a host that matches the input MoRef.
Function Get-VMHostByMoRef() {
<#
.SYNOPSIS
Fetches host name by input MoRef and Cluster to look in
.DESCRIPTION
Fetches host name by input MoRef and Cluster to look in
.PARAMETER MoRef
The MoRef of the host system
.PARAMETER Cluster
The name of the cluster to do the lookup in
.EXAMPLE
PS F:\> Get-VMHostByMoRef -MoRef HostSystem-host-28 -Cluster MyCluster01
.LINK
http://www.shogan.co.uk
.NOTES
Created by: Sean Duffy
Date: 22/02/2013
#>
[CmdletBinding()]
param(
[Parameter(Position=0,Mandatory=$true,HelpMessage="Specify the Host MoRef name you would like to query for it's friendly name.",
ValueFromPipeline=$true,ValueFromPipelineByPropertyName=$true)][String]$MoRef,[Parameter(Position=1,Mandatory=$true,HelpMessage="Specify the Cluster to search hosts in.",
ValueFromPipeline=$true,ValueFromPipelineByPropertyName=$true)][String]$Cluster
)
process {
$AllHosts = Get-Cluster $Cluster | Get-VMHost
$thehost = $AllHosts | Where {$_.ExtensionData.MoRef -match $MoRef} | Select-Object -Property Name
return $thehost
}
}
Here is a quick sample of the output when called directly from the PowerCLI prompt (note the MoRef of “host-22” used to find the real host name of “esxi02.homelab.local”: 
Hopefully this may be of use to some – add it to your PowerCLI script/function toolkit or throw it into your PowerShell $profile for easy access in the future!