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Running a Windows PowerShell Workflow

Published: June 24, 2013

Updated: June 24, 2013

Applies To: Windows 8, Windows PowerShell 4.0, Windows Server 2012, Windows Server 2012 R2



After setting up your Windows PowerShell Workflow environment as described in Configuring Your Workflow Environment, and authoring or finding a workflow, you are ready to start running your workflow.

Running a workflow is like running any Windows PowerShell command. You can run the Get-Command cmdlet to discover workflows, and run Get-Help to get available help about workflows. Running a workflow is as simple as entering the verb-noun name of the workflow (or verb-noun–PsComputerNamemanagednode1, managednode2).

This topic contains the following sections.

You create a new session to connect to the computer that is running your workflow if you are starting the workflow from the beginning, or if you have closed (and not merely disconnected from) an earlier session that is connected to the workflow computer. If you are reconnecting to a workflow that is already in progress, you do not need to create a new session to connect to the computer that is running the workflow; you can connect to the existing session. The following procedure is an example of how to create a new session on a local or remote computer.

  1. Start Windows PowerShell with the Run as administrator option as described in Starting Windows PowerShell. You do not need to run Windows PowerShell with elevated user rights (Run as Administrator) if you are connecting from a remote computer.

  2. Start a remote Windows PowerShell session that is connected to the computer that you want to run your workflow, and save the session in a variable. This session can be on your local computer (localhost) or on a remote computer. For example, the following commands start a remote session on the local computer, and save the session in the $WFServer variable. The session is configured to use the default workflow session configuration that is described in Configuring Your Workflow Environment.

    In the following example, the command starts a workflow session on the local computer, and saves the session in the $WFServer variable. By using the New-PSWorkflowSession cmdlet, the session is configured to use the default workflow session configuration.

    $WFServer = New-PSWorkflowSession

    In the following example, the command starts the workflow session on a different computer, Server01, and saves the session in the $WFServer variable.

    $WFServer = New-PSWorkflowSession -ComputerName Server01 -credential DomainName\UserName

    Because the workflow server session runs on a remote computer in the preceding example, the user must provide explicit credentials. Explicit credentials are not required if the session configuration includes RunAs functionality, where all users share a set of credentials that are defined in the session configuration.

  3. Alternatively, you can create a new Windows PowerShell session by running the New-PSSession cmdlet, as described in New-PSSession. When you run New-PSSession instead of New-PSWorkflowSession, you can add the ConfigurationName parameter to specify a session configuration other than the default Windows PowerShell Workflow session configuration. To specify the default Windows PowerShell Workflow session configuration, add –ConfigurationName Microsoft.PowerShell.Workflow to the command.

You can now run workflows in this session, either from a module, or by starting a standalone XAML or Windows PowerShell script-based workflow.

If you are reconnecting to a workflow that you have already started, you can specify the job ID or name of the workflow to reconnect. You can also run the Connect-PSSession cmdlet to reconnect to a disconnected session that was connected to the computer that is running your workflow.

  1. Start a new session that is connected to the computer that is running your workflow. Save the session connection in a variable, as shown in the following example.

    $WFServer=New-PSWorkflowSession -ComputerName Server01

  2. Get the list of jobs that are running on the computer that you specified in step 1.

    Invoke-Command $WFServer {Get-Job}

  3. In the results, locate the workflow to which you want to reconnect.

  4. If the workflow is not suspended, go on to the next step. To resume a suspended workflow, run the following command, where $WFServer represents the variable into which your session connection is saved.

    Invoke-Command $WFServer {Resume-Job <Job name or ID>}

  5. To get information about the progress and status of a workflow, run Receive-Job as shown in the following example.

    Invoke-Command $WFServer {Receive-Job <Job name or ID>}

The following procedure shows how to run a workflow that is packaged in a module. This step is required only if you did not specify a root module or a nested module key in the module manifest.

  1. If you do not have an existing active session to the computer on which you want to run the workflow, create a new session as described in To create a new workflow session.

  2. Copy the module directory that you created in Saving Your Workflow in a Module to the computer on which you are running the workflow. For convenience, copy it to the Modules directory (for example, $env:C:\Users\<user_name>\Documents\WindowsPowerShell\Modules) on that computer.

  3. Optionally, import the module into the session that is connected to the computer running the workflow by using either of the following two commands. In Windows PowerShell 3.0, modules are imported into a session automatically the first time a user runs a cmdlet that is part of the module. Add Invoke-Command to run an Import-Module command in the workflow server session. The optional Verbose parameter displays the functions that the module adds to the session.

    Invoke-Command -Session $<name of session variable> -ScriptBlock {Import-Module <ModuleName> -Verbose}

    For example, the following command imports the RoleManager module into the workflow server session.

    Invoke-Command $WFServer {Import-Module RoleManager -Verbose}

    The Import-Module cmdlet imports workflows into your session as functions. You can now run the workflows in the session that is connected to the computer on which you want to run your workflow.

  4. Type the workflow name, and press Enter to start the workflow. For example, to start the workflow that was saved in a module in Saving Your Workflow in a Module, type Install-Role -PSComputerName <managed_node_names>, and then press Enter.

The following procedure explains how to run a XAML-based workflow that is not in a module in the session that is connected to the computer on which you want to run your workflow. After you import the workflow XAML files, you can use the workflows in your workflow server session. For more information about XAML-based workflows that you can use with Windows PowerShell Workflow, see “Creating and importing workflows using the Visual Studio Workflow Designer” in Getting Started with Windows PowerShell Workflow.

  1. Start a workflow server session, as described in To create a new workflow session.

  2. Run the following command to import the workflow XAML file into your workflow server session.

    Invoke-Command -Session $<name of session variable> -Scriptblock {Import-Module <Path_To_Xaml_File>}

    For example, the following command imports the Install-Role and Set-Role workflows into the workflow server session.

    Invoke-Command $WFServer {Import-Module -Path D:\Temp\Install-Role.xaml, D:\Temp\Set-Role.xaml}

You can use the AsJob workflow common parameter that is added to all workflows in Windows PowerShell to run a workflow as a Windows PowerShell job. For more information about jobs, see about_Jobs. You can use Job cmdlets to start, stop, suspend, or resume workflows. To run a workflow as a job, enter a command in the following format.

Verb-Noun -PSComputerName ManagedNode01, ManagedNode02 -AsJob

noteNote
Invoke-Command and the variable in which your workflow session is stored (in this example, $WFServer) are necessary in the following commands only if you have not already created a session that is connected to the computer running your workflow. If you are already in that session, you need only to run the commands that are inside braces.

  • The following are examples of running and managing workflows by using Job cmdlets.

    • Use the AsJob parameter to run the Install-Role workflow as a job. The PSComputerName parameter specifies the computers on which the roles are installed. In the following example, a workflow is run as a job.

      Invoke-Command $WFServer {Install-Role -PSComputerName Server01, Server02 -AsJob}

    • Get all the jobs that are running in the workflow server session. Each workflow instance is run as a separate job. The jobs are shown as running on the local computer (localhost), because the job object is created locally in the workflow server session, even though the job is running on two different remote computers.

      Invoke-Command $WFServer {Get-Job}

      The results are similar to the following.

      Id  Name  State      HasMoreData  Location   Command
      --  ----  -----      -----------  --------   -------
      1   Job1  Running    True         Server01  install-role
      2   Job2  Running    True         Server02  install-role
      
      
    • Get the workflow jobs that affect a specific managed node, by adding the Filter parameter.

      Invoke-Command $WFServer {Get-Job -Filter {PSComputerName = "Server01"}

    • Get the status of a job.

      Invoke-Command $WFServer { (get-job -name Job1).state}

    • Wait for a job to finish.

      Invoke-Command $WFServer {wait-job -name Job1}

    • Get the results of a job.

      Invoke-Command $WFServer {receive-job -name Job1}

    • Delete or remove a job.

      Invoke-Command $WFServer {remove-job -name Job1}

  • The following are examples of suspending and resuming workflows by using Job cmdlets.

    • Suspend a workflow as a job.

      Invoke-Command $WFServer {suspend-job -name Job1}

    • Resume a suspended workflow as a job.

      Invoke-Command $WFServer {resume-job -name Job1}

Workflows are added to a session as functions. You can use the same commands that you would use to examine functions to examine your workflows.

noteNote
If you are already in the session that is connected to the computer on which your workflow is running, you do not need to add Invoke-Command $variable. Run only the commands that are inside braces.

  • The following commands are examples of information that you can get about your workflow.

    • Find functions that a workflow module added to your session.

      Invoke-Command $WFServer {get-command -module RoleManager}

    • Examine a workflow or function.

      Invoke-Command $WFServer {ls function:\Install-Role}

    • Use the Get-Command cmdlet to display the properties of a workflow function.

      Invoke-Command $WFServer {get-command Install-Role }

    • Use the Get-Command cmdlet to get the syntax of a workflow function.

      Invoke-Command $WFServer {get-command install-role -syntax}

    • Examine the objects that a workflow function returns.

      Invoke-Command $WFServer {install-role | get-member}

You can add checkpoints to the workflows that you run and suppress its default checkpoints. You cannot remove or suppress explicit checkpoints in a workflow.

A checkpoint is a snapshot of the workflow state and data that is taken while the workflow runs. The checkpoint is saved to disk on the computer on which the workflow runs or to a SQL database. If the workflow is suspended or interrupted, it can be resumed from the most recent checkpoint, rather than restarting.

Most workflows have explicit checkpoints. Additional checkpoints are useful when the network is not stable, the workflow is frequently interrupted, or the workflow is running on a very large number of devices, However, adding too many checkpoints can make the workflow run very slowly. Be sure that the time it takes to write the checkpoint data to disk is less than the time it would take to rerun the workflow if it is interrupted.

To adjust the checkpoints in a workflow, use the PSPersist workflow common parameter. The following are the valid values.

$True
Adds a checkpoint after each activity. These checkpoint are additions to the default checkpoints taken at the beginning and end of the workflow and any checkpoints that are explicitly specified in the workflow.

$False
Suppresses the default checkpoints that are taken at the beginning and end of the workflow. This value does not affect explicit checkpoints.

The following examples run the Set-WorkflowState workflow with the PSPersist parameter set to $True and $False.

PS C:\>Set-WorkflowState -PSPersist $True
PS C:\>Set-WorkflowState -PSPersist $False

If Help is available for a workflow that you are running, you can get help about what the workflow does, and how to run it, by typing the following, and then pressing Enter.

Get-Help <WorkflowVerb-WorkflowNoun>

For more information about how to write help for a workflow, see Writing Help for a Script Workflow.

Error logs for workflows are stored on the computer that is running the workflow (sometimes called the workflow server). You can find them in the following Event Tracing for Windows (ETW) channel, or path in the Event Viewer snap-in. Event ID 45079 shows each activity that is run.

Applications and Services Logs\Microsoft\Windows\PowerShell

See Also

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