Orchestrate your scripts with workflows – Part 1

Availables within PowerShell v3, workflows were created to bring you a solution to orchestrate and coordinate your multimachines sequences. Workflows are robust, reliable and handle long running tasks!

According my experience, many peoples know about them, but not so many administrators use them. Let’s have a full visit about using them, and building them.

Write a simple workflow

Writting a workflow is like writting a function, it’s really easy !

Workflow Get-ComputerDisk {
    InlineScript {

PS F:\PowerShell> Get-ComputerDisk

Name           Used (GB)     Free (GB) Provider      Root                                CurrentLocation PSComputerName
----           ---------     --------- --------      ----                                --------------- --------------
Alias                                                                                                    localhost
C                 106,27          5,18               C:\                                 ...ON\Documents localhost
Cert                                                 \                                                   localhost
D                    ,04           ,06               D:\                                                 localhost
E                  46,31          2,42               E:\                                                 localhost
Env                                                                                                      localhost
F                 205,90        676,78               F:\                                                 localhost
Function                                                                                                 localhost
G                                                    G:\                                                 localhost
H                 177,64        120,45               H:\                                                 localhost
HKCU                                                 HKEY_CURRENT_USER                                   localhost
HKLM                                                 HKEY_LOCAL_MACHINE                                  localhost
Variable                                                                                                 localhost
WSMan                                                                                                    localhost

Why InlineScript ?

The InlineScript activity runs commands in a shared Windows PowerShell session in a workflow. This activity is valid only in workflows.

It means variables outside the InlineScript can only be used by specifying $using:$yourvar. Exemple from technet page

workflow Test-Workflow
            $a = 3

            # Without $Using, the $a workflow variable is not visible
            # in inline script.
            InlineScript {"Inline A0 = $a"}
            # $Using imports the variable and its current value.
            InlineScript {"Inline A1 = $Using:a"}

PS C:\> Test-Workflow
Inline A0 = 
Inline A1 = 3

You can also execute scriptblock on remote target with InlineScript, we’ll see how later in this post.

Advanced workflows technics

Declare parameters

Like a function, you can use parameters with your workflow (of course). By the way, there are limits declaring parameters in a workflow, you can’t use sophisticated parameters, like running test-path, using .net type shortcut like ipadress, etc..

Workflow Test-Workflow {
    param (
        [String]$a = "Ille-Et-Vilaine",
        [String]$b = "Bzh"

    InlineScript {
        "Departement: $USING:a"
        "Region: $USING:b"

PS F:\PowerShell> Test-Workflow

Departement: Ille-Et-Vilaine
Region: Bzh
PS F:\PowerShell> Test-Workflow -a "Test" -b "PowerShell"
Departement - Test
Region - PowerShell

If you use InlineScripts, you don’t have to declare parameters in param section if you use Workflows common parameters with the scope parameter-level ! You can find the complete list of theses parameters here. I’ll explain the ones i found the most usefull.



Sequences ( a squence is a group of statements)  can be used between parallel brackets in order to parallelize them. As an exemple is better than all words, here we go !

workflow Start-ParallelWorkflow {

    Parallel {
        # Sequence 1
        Sequence {


        # Sequence 2
        Sequence {



Another possibility available only in workflows is foreach with -parallel switch !


workflow Start-ParallelWorkflow {

    Foreach -parallel ($a in 1..5) {
        Write-Host $a



Run a workflow


The easiest solution is to invoke the workflow in the same script like done in the previous example.

Just use the workflow name like you’ll do for a function or a cmdlet !


If you want to use remoting in your workflows it’s also possible, and a piece of cake with InlineScript  !

To do this, create the following workflow as example

workflow Test-InlineScriptRemoting {

    InlineScript {

        Write-Host "I'm running on $Using:PScomputerName"


    InlineScript {

        Write-Host "I'm running on $Using:PScomputerName"

    } -PSComputerName


And run it!

Test-InlineScriptRemoting -PSComputerName srvdc01

And taddaah!

PS F:\PowerShell> Test-InlineScriptRemoting -PSComputerName srvdc01
I'm running on srvdc01
I'm running on

Ok, this is all for this first part. Next time will talk about:

  • Common parameters
  • Controlling the flow of your workflows
  • Handle XAML in a workflow
  • Troubleshooting workflows


Hope you enjoy it!

See ya !