Generate Azure SPN script, based on http://blogs.msdn.com/b/visualstudioalm/archive/2015/10/04/automating-azure-resource-group-deployment-using-a-service-principal-in-visual-studio-online-build-release-management.aspx

new-azurespn.ps1

  param
  (
      [Parameter(Mandatory=$true, HelpMessage="Enter Azure Subscription name. You need to be Subscription Admin to execute the script")]
      [string] $subscriptionName,
  
      [Parameter(Mandatory=$true, HelpMessage="Provide a password for SPN application that you would create")]
      [string] $password,
  
      [Parameter(Mandatory=$false, HelpMessage="Provide a SPN role assignment")]
      [string] $spnRole = "owner"
  )
  
  
  #Initialize
  $ErrorActionPreference = "Stop"
  $VerbosePreference = "SilentlyContinue"
  if([system.text.RegularExpressions.regex]::match($ENV:username, "^[a-zA-Z0-9]+$").Success -eq   $false){
    Write-Host 'replace $username inital value except ANK charactors'
    return
  }
  
  $userName = $ENV:username
  $newguid = [guid]::NewGuid()
  Import-Module Azure -ErrorAction SilentlyContinue
  
  #Initialize subscription
  $isAzureModulePresent = Get-Module -Name AzureRM -ListAvailable

  Write-Output "Provide your credentials to access Azure subscription $subscriptionName" -Verbose
  Login-AzureRmAccount -SubscriptionName $subscriptionName
  $azureSubscription = Get-AzureRmSubscription -SubscriptionName $subscriptionName

  $subscriptionName = $subscriptionName.Replace(' ','_') 
  $displayName = "VSO." + $userName + '.' + $subscriptionName + '.' + $newguid
  $homePage = "http://" + $displayName
  $identifierUri = $homePage

  $connectionName = $azureSubscription.SubscriptionName
  $tenantId = $azureSubscription.TenantId
  $id = $azureSubscription.SubscriptionId
  
  
  #Create a new AD Application
  Write-Output "Creating a new Application in AAD (App URI - $identifierUri)" -Verbose
  $azureAdApplication = New-AzureRmADApplication -DisplayName $displayName -HomePage $homePage -  IdentifierUris $identifierUri -Password $password -Verbose
  $appId = $azureAdApplication.ApplicationId
  Write-Output "Azure AAD Application creation completed successfully (Application Id: $appId)" -  Verbose
  
  
  #Create new SPN
  Write-Output "Creating a new SPN" -Verbose
  $spn = New-AzureRmADServicePrincipal -ApplicationId $appId
  $spnName = $spn.ServicePrincipalName
  Write-Output "SPN creation completed successfully (SPN Name: $spnName)" -Verbose
  
  
  #Assign role to SPN
  Write-Output "Waiting for SPN creation to reflect in Directory before Role assignment"
  sleep 20
  Write-Output "Assigning role ($spnRole) to SPN App ($appId)" -Verbose
  New-AzureRmRoleAssignment -RoleDefinitionName $spnRole -ServicePrincipalName $appId
  Write-Output "SPN role assignment completed successfully" -Verbose
  
  
  #Print the values
  Write-Output "`nCopy and Paste below values for Service Connection" -Verbose
  Write-Output "***************************************************************************"
  Write-Output "Connection Name: $connectionName(SPN)"
  Write-Output "Subscription Id: $id"
  Write-Output "Subscription Name: $connectionName"
  Write-Output "Service Principal Id: $appId"
  Write-Output "Service Principal key: <Password that you typed in>"
  Write-Output "Tenant Id: $tenantId"
  Write-Output "***************************************************************************"