Automating the deployment of ESXi hosts using PowerShell requires the use of the VMware PowerCLI module, which provides cmdlets to interact with vCenter Server and automate various vSphere tasks. Below is a basic PowerShell script to automate the deployment of ESXi hosts using Auto Deploy in a vSphere environment:

# Load VMware PowerCLI module
Import-Module VMware.PowerCLI

# Set vCenter Server connection details
$vcServer = "vcenter.example.com"
$vcUsername = "administrator@vsphere.local"
$vcPassword = "your_vcenter_password"

# Set Auto Deploy Server details
$autoDeployServer = "autodeploy.example.com"

# Set deployment rules and policies
$deployRuleName = "ESXi-Deployment-Rule"
$deployRuleDescription = "Auto Deploy ESXi Hosts Rule"
$deployPolicyName = "ESXi-Deployment-Policy"
$deployPolicyDescription = "Auto Deploy ESXi Hosts Policy"

# Set ESXi host details
$esxiHostName = "esxi-host-01"
$esxiHostProfile = "HostProfile-ESXi"
$esxiDatastore = "Datastore-01"
$esxiCluster = "Cluster-01"

# Connect to vCenter Server
Connect-VIServer -Server $vcServer -User $vcUsername -Password $vcPassword

# Create an Auto Deploy rule
New-DeployRule -Name $deployRuleName -Description $deployRuleDescription -Item $esxiHostName -Pattern "vendor=vmware,rule=esxi5.5" -DeployPolicy $deployPolicyName

# Create an Auto Deploy deployment policy
New-DeployRule -Name $deployPolicyName -Description $deployPolicyDescription -Item $esxiCluster -Pattern "vendor=vmware,rule=esxi5.5"

# Register the Auto Deploy Server
Register-DeploySoftwarePackage -DeployServer $autoDeployServer -Rule $deployPolicyName -DeployRule $deployRuleName

# Start the Auto Deploy Service
Start-VMHostProfile -Host $esxiHostName -Profile $esxiHostProfile -Confirm:$false

# Disconnect from vCenter Server
Disconnect-VIServer -Server $vcServer -Confirm:$false

Before running the script, make sure to modify the variables with appropriate values based on your environment.

Please note that this script assumes that you have already set up the Auto Deploy infrastructure, including the Auto Deploy Server, rules, policies, and image profiles. Additionally, ensure that you have appropriate permissions to perform the tasks mentioned in the script.

It is essential to thoroughly test the script in a non-production environment before using it in a production environment. Automated tasks like host deployment can have a significant impact on your infrastructure, so it’s crucial to verify and validate the script’s behavior before deployment.