{"id":2441,"date":"2012-03-16T20:08:19","date_gmt":"2012-03-16T20:08:19","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/powershell\/2012\/03\/16\/when-windows-powershell-met-workflow\/"},"modified":"2024-02-28T11:32:14","modified_gmt":"2024-02-28T19:32:14","slug":"when-windows-powershell-met-workflow","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/powershell\/when-windows-powershell-met-workflow\/","title":{"rendered":"When Windows PowerShell Met Workflow"},"content":{"rendered":"

Meet the new kid on the block! Windows PowerShell Workflow <\/b>(PSWF) is the latest addition to the Windows PowerShell family. <\/span><\/p>\n

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First, let\u2019s establish the context for the decision to integrate workflows into Windows PowerShell. It starts with cloud computing and Windows-based datacenters. Cloud computing provides a set of highly available, scalable computing services that leverage high volume components (servers, disks, RAM, etc.) High volume components are less reliable than their tier 1 counterparts and even those occasionally fail. The key to cloud computing is to use software to deliver a reliable service in spite of failures. Cloud computing management needs to be reliable in spite of failures. This is where workflows come in. Workflows are typically long-running scripts that are designed to survive component or network errors and reboots. <\/span><\/p>\n

Automation is the heart of creating and running private and public clouds at scale. By automating administration tasks and operations, you decrease cost and improve repeatability, quality, auditing and logging. This allows you to increase your server-to-admin ratio, take on more business and increase the value of your employees by freeing them up to deliver higher value functions. As an example, <\/span>Erin Chapple explains<\/span><\/a>:<\/span><\/p>\n

\u201c<\/i>Server Manager accomplishes this by leveraging the multi-machine management capabilities of WMI, Windows PowerShell and Windows PowerShell\u2019s new workflow capabilities. Virtually every operation done using Server Manager can also be done via Windows PowerShell\u201d<\/i>.<\/span><\/p><\/blockquote>\n

While building Windows PowerShell Workflow, we took advantage of the scalability and maturity of Windows Workflow Foundation 4.0 (WF) to bring the benefits of workflows — long running capability and reliability — to scripters and the Windows PowerShell ecosystem. <\/span><\/p>\n

In one sentence, Windows PowerShell Workflow is all about:<\/span><\/p>\n

Reliably executing long-running tasks across multiple computers, devices or IT processes<\/span><\/b><\/p><\/blockquote>\n

Until Windows PowerShell 3.0, the approach to solving this problem has been to combine Windows PowerShell and Windows Workflow Foundation with proprietary implementations. As part of our planning process, we talked to many customers and found many cloud providers and hosters who took WF and Windows PowerShell and put them together. Hundreds of design decisions need to be made during that process so the workflows for any implementation did not work with other solutions. We wanted to deliver the definitive integration of these two technologies in a way that could be used out-of-the box or as a reusable library in a third-party solution. For example, we have designed our implementation with extension points that allow applications to host our engine in a fault tolerant, scale out configuration with detailed auditing. The goal is for the community to write workflows that work with our in-box solution and then light up without modification in third-party solutions.<\/span><\/p>\n

In Windows 8, we introduce Windows PowerShell Workflow with two key goals:<\/span><\/p>\n

– Minimizing the complexity of automating across a large number of cloud or datacenter computers and devices.<\/span><\/p><\/blockquote>\n

– Creating an ecosystem<\/b> where ISVs and partners can build solutions on top of Windows PowerShell Workflow and the artifacts<\/b> can be shared with the community and used in any solution. <\/span><\/p><\/blockquote>\n

To achieve these goals, we decided to invest in the following areas for our first PSWF release:<\/span><\/p>\n

– Simplified workflow authoring<\/span><\/p><\/blockquote>\n

– Leverage your existing knowledge<\/span><\/p><\/blockquote>\n

– Reliable workflow execution<\/span><\/p><\/blockquote>\n

– Performance and Scalability<\/span><\/p><\/blockquote>\n

Simplified Workflow Authoring<\/span><\/h5>\n

Windows PowerShell Workflow enables IT professionals and developers to author sequences of activities that are long-running, repeatable, frequent, parallelizable, interruptible, suspendable, and\/or restartable as workflows. <\/span><\/p>\n

A workflow is a set of activities. An activity is an individual step within a workflow that performs a defined task, such as getting the list of virtual machines in a host computer.<\/span><\/p>\n

Leverage Your Existing Knowledge<\/span><\/h5>\n

We designed PSWF with our sacred vow in mind: <\/span><\/p>\n

We respect your investment in learning Windows PowerShell by reusing concepts over and over to make sure learning Windows PowerShell was the best thing you ever did.<\/b><\/b><\/span><\/p>\n

This is very important to us: making the most of your time and leveraging the investment you have already made in Windows PowerShell instead of asking you to learn a whole new language for authoring workflows. We care deeply about your ROI, so instead of creating new workflow abstractions, we used and built Windows PowerShell abstractions with workflow semantics.<\/b><\/span><\/p>\n

At the same time, we want to work within the existing Windows Workflow Foundation ecosystem. This is why you have two options for writing a Windows PowerShell workflow:<\/span><\/p>\n

– PowerShell script-based workflow: If you know how to write PowerShell scripts, you can reuse your assets and skills and learn a few new constructs to create workflows. For instance:<\/span><\/p>\n