PowerShell Function to create a Service Principal and return the script to onboard a machine to Azure Arc

Get-AzureArcOnboardingScript.ps1

[CmdletBinding()]
param (
    [Parameter()]
    [System.String]
    $ServicePrincipalName = 'AzureArcMachineOnboarding',

    [Parameter()]
    [ValidateSet('Linux','Windows')]
    [System.String]
    $OperatingSystem = 'Linux',

    [Parameter(Mandatory = $true)]
    [System.String]
    $ResourceGroup,

    [Parameter(Mandatory = $true)]
    [System.String]
    $TenantId,

    [Parameter(Mandatory = $true)]
    [System.String]
    $Location,

    [Parameter(Mandatory = $true)]
    [System.String]
    $SubscriptionId
)

Select-AzSubscription -SubscriptionId $SubscriptionId

Write-Verbose -Message 'Registering provider namespaces: Microsoft.HybridCompute, Microsoft.GuestConfiguration'
Register-AzResourceProvider -ProviderNamespace 'Microsoft.HybridCompute'
Register-AzResourceProvider -ProviderNamespace 'Microsoft.GuestConfiguration'

Write-Verbose -Message ('Creating Service Principal {0}' -f $ServicePrincipalName)
$servicePrincipal = New-AzADServicePrincipal -DisplayName $ServicePrincipalName -Role "Azure Connected Machine Onboarding"
$credential = New-Object -TypeName pscredential -ArgumentList 'temp', $servicePrincipal.Secret
$servicePrincipalPassword = $credential.GetNetworkCredential().password
$servicePrincipalId = $servicePrincipal.ApplicationId

if ($OperatingSystem -eq 'Linux') {
    $script = @"
# Download the installation package
wget https://aka.ms/azcmagent -O ~/install_linux_azcmagent.sh

# Install the hybrid agent
bash ~/install_linux_azcmagent.sh

# Run connect command
sudo azcmagent connect \
  --service-principal-id "$servicePrincipalId" \
  --service-principal-secret "$servicePrincipalPassword" \
  --resource-group "$ResourceGroup" \
  --tenant-id "$TenantId" \
  --location "$Location" \
  --subscription-id "$SubscriptionId"
"@
} else {
    $script = @"
# Download the package
function download() {$ProgressPreference="SilentlyContinue"; Invoke-WebRequest -Uri https://aka.ms/AzureConnectedMachineAgent -OutFile AzureConnectedMachineAgent.msi}
download

# Install the package
msiexec /i AzureConnectedMachineAgent.msi /l*v installationlog.txt /qn | Out-String

# Run connect command
& "`$env:ProgramFiles\AzureConnectedMachineAgent\azcmagent.exe" connect `
  --service-principal-id "$servicePrincipalId" `
  --service-principal-secret "$servicePrincipalPassword" `
  --resource-group "$ResourceGroup" `
  --tenant-id "$TenantId" `
  --location "$Location" `
  --subscription-id "$SubscriptionId"
"@
}

return $script