4.1

What to do next
You can define long-running workflows.
Running a Workflow on a Selection of Objects
You can automate repetitive tasks by running a workflow on a selection of objects. For example, you can create
a workflow that takes a snapshot of all the virtual machines in a virtual machine folder, or you can create a
workflow that powers off all the virtual machines on a given host.
You can use one of the following methods to run a workflow on a selection of objects.
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Run the Library > vCenter > Batch > Run a workflow on a selection of objects workflow.
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Create a workflow that calls the Orchestrator > Start workflows in a series or Start workflows in
parallel workflows.
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Create a workflow that obtains an array of objects and runs a workflow on each object in the array in a
loop of workflow elements.
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Run a workflow from JavaScript by calling the Workflow.execute() method in a For loop in a scripted
element in a workflow.
Which method you choose to run a workflow on a selection of objects depends on the workflow to run and
can affect the performance of the workflow. For example, running the Run a workflow on a selection of objects
workflow is the simplest way to run a workflow on multiple objects and requires no workflow development,
but it can only run workflows that take a single input parameter.
Creating a workflow that calls the Start workflows in a series or Start workflows in parallel workflows allows
you to run on multiple objects workflows that take more than one input parameter. The calling workflow must
create a properties array to pass the input parameters to the Start workflows in a series or Start workflows in
parallel workflow. These workflows are only for use in other workflows. Do not run them directly.
Running a workflow in a For loop in a scripted element is faster than running a workflow in a loop of workflow
elements, but it is less flexible and limits the potential for reuse. Most importantly, running a workflow in a
scripted loop loses the checkpointing that Orchestrator performs when it starts each element in a workflow
run. As a consequence, if the Orchestrator server stops while the scripted loop is running, when the server
restarts, the workflow will resume at the beginning of the scripted element, repeating the whole loop. If the
Orchestrator server stops while running a workflow with a loop of workflow elements, the workflow will
resume at the specific element in the loop that was running when the server stopped.
For more information about the Batch workflows, see the vCenter Orchestrator Administration Guide.
How to create a workflow that runs a workflow on an array of objects in a loop of workflow elements is
demonstrated in “Develop a Complex Workflow,” on page 89.
How to run a workflow in a scripted For loop is demonstrated in “Workflow Scripting Examples,” on
page 126.
Implement the Start Workflows in a Series and Start Workflows in Parallel
Workflows
You can use the Start workflows in a series and Start workflows in parallel workflows to run a workflow on a
selection of objects.
You cannot run the Start workflows in a series and Start workflows in parallel workflows directly. You must
include them in another workflow that you create. To use the Start workflows in a series and Start workflows
in parallel workflows to run a workflow on a selection of objects, you must obtain the objects on which to run
the workflow. You pass these objects and any other input parameters that the workflow requires to the
workflow as an array of properties. The Start workflows in a series and Start workflows in parallel workflows
emit the results of running the workflow on the selection of objects as an array of WorkflowToken objects.
vCenter Orchestrator Developer's Guide
56 VMware, Inc.