Startup-VM.ps1

<#
.SYNOPSIS
    Provides an option to startup selected VMs  

.DESCRIPTION
    This runbook can be used for starting up a set of Azure RM VMs mentioned in the parameter 
   

.PARAMETER connectionName
    String value for Azure Runbook Connection Name. The default value of this should be AzureRunAsConnection
.PARAMETER vmNames
    String value for a comma separated list of vm names to start

.EXAMPLE
    Startup-VM -connectionName "AzureRunAsConnection" -vmNames "testvm,testvm2"

.NOTES
	Author: Tiklu Ganguly 
	Last Updated: 10/17/2016   
#>

workflow Startup-VM
{
    param
    (
    [parameter(Mandatory=$false)]
    [String]$connectionName = "AzureRunAsConnection",  
    [parameter(Mandatory=$true)]
    [String]$vmNames  
    )

    $currentTime = (Get-Date).ToUniversalTime()

    try
    {
        # Get the connection "AzureRunAsConnection "
        $servicePrincipalConnection=Get-AutomationConnection -Name $connectionName         

        "Logging in to Azure..."
        Add-AzureRmAccount `
            -ServicePrincipal `
            -TenantId $servicePrincipalConnection.TenantId `
            -ApplicationId $servicePrincipalConnection.ApplicationId `
            -CertificateThumbprint $servicePrincipalConnection.CertificateThumbprint 
    }
    catch {
        if (!$servicePrincipalConnection)
        {
            $ErrorMessage = "Connection $connectionName not found."
            throw $ErrorMessage
        } else{
            Write-Error -Message $_.Exception
            throw $_.Exception
        }
    }

    try
    {
        $vms = Get-AzureRmVM

        ForEach($vm in $vms)
        {
            if($vmNames -match $vm.Name)
            {
                Write-Output "Starting $($vm.Name)"
                $stat=$vm|Start-AzureRmVM
                if($stat.IsSuccessStatusCode)
                {
                    Write-Output "Started $($vm.Name)"
                }
                else
                {
                    Write-Output "Unable to Start $($vm.Name) for $($stat.ReasonPhrase)"
                }
            }
        }
    }
    catch
    {
        $errorMessage = $_.Exception.Message
        Write-Error -Message "Unexpected error $errorMessage" 
        throw $_.Exception
    }
    finally
    {
        Write-Output "Runbook finished (Duration: $(("{0:hh\:mm\:ss}" -f ((Get-Date).ToUniversalTime() - $currentTime))))"
    }
}