PowerCLI Basics for VMware Administrators

If you manage VMware infrastructure and you’re not using PowerCLI, you’re doing the same tasks manually that a few lines of PowerShell would automate. PowerCLI is VMware’s PowerShell module for vSphere management, and once you get comfortable with the basics, it becomes an essential tool for everything from inventory reporting to bulk configuration changes.

Getting Started

Install PowerCLI from the PowerShell Gallery — the clean, current way:

Install-Module -Name VMware.PowerCLI -Scope CurrentUser

Connect to your vCenter:

Connect-VIServer -Server vcenter.company.com -Credential (Get-Credential)

For scripted connections without interactive credential prompts, store credentials securely (PowerShell credential export or a secrets manager) and pass them programmatically.

Essential Commands

A few PowerCLI commands that I use constantly:

Get-VM: Lists VMs. Combine with -Name for specific VMs or leave without arguments for all. Pipe to Select for specific properties:

Get-VM | Select Name, PowerState, NumCpu, MemoryGB | Sort Name

Get-VMHost: Lists ESXi hosts. Useful for inventory and checking host status:

Get-VMHost | Select Name, ConnectionState, Version, MemoryTotalGB, MemoryUsageGB

Get-Datastore: Lists datastores and their usage:

Get-Datastore | Select Name, CapacityGB, FreeSpaceGB, @{N='UsedGB';E={[math]::Round($_.CapacityGB - $_.FreeSpaceGB,1)}} | Sort FreeSpaceGB

This is the command I run first when someone reports storage issues — it shows every datastore’s free space instantly across the entire cluster.

Practical Scripts I Use Regularly

Find all VMs with snapshots:

Get-VM | Get-Snapshot | Select VM, Name, Created, SizeGB | Sort SizeGB -Descending

Snapshot accumulation is a quiet killer in VMware environments. This reveals forgotten snapshots that are consuming datastore space.

Check all VMs without VMware Tools installed:

Get-VM | Where-Object {$_.ExtensionData.Guest.ToolsStatus -ne 'toolsOk'} | Select Name, @{N='ToolsStatus';E={$_.ExtensionData.Guest.ToolsStatus}}

Get VMs with CPU or memory reservations set (reservations affect DRS balancing):

Get-VM | Where-Object {$_.ExtensionData.ResourceConfig.CpuAllocation.Reservation -gt 0 -or $_.ExtensionData.ResourceConfig.MemoryAllocation.Reservation -gt 0} | Select Name

Bulk Operations

PowerCLI shines for bulk operations. Examples:

Set VM startup policy for all VMs in a folder:

Get-Folder "Production" | Get-VM | Get-VMStartPolicy | Set-VMStartPolicy -StartAction PowerOn -StartOrder 1

Move all VMs from one datastore to another (requires vMotion/Storage vMotion):

Get-Datastore "OldDatastore" | Get-VM | Move-VM -Datastore "NewDatastore"

Apply a tag to all VMs matching a naming pattern:

Get-VM | Where-Object {$_.Name -like "WEB-*"} | New-TagAssignment -Tag (Get-Tag "tier-web")

Building Scheduled Reports

One of the most valuable uses of PowerCLI in SMB environments: scheduled health reports. A script that emails you a summary of datastore space, snapshot status, host health, and powered-off VMs every morning takes an hour to write and saves that time every week indefinitely.

$report = Get-Datastore | Select Name, 
    @{N='FreePct';E={[math]::Round(($_.FreeSpaceGB/$_.CapacityGB)*100,1)}} |
    Where-Object {$_.FreePct -lt 30}

if ($report) {
    Send-MailMessage -To "[email protected]" -Subject "Datastore Alert" -Body ($report | Out-String)
}

That’s a basic datastore space alert script. The output is readable, the logic is simple, and it’s been running unmodified in multiple client environments for years.