4.1

5 Follow the instructions in the input parameters dialog box to provide the information that the workflow
requires.
You provided information to a workflow that was waiting for user input during its run.
Calling Workflows Within Workflows
Workflows can call on other workflows during their run. A workflow can start another workflow either because
it requires the result of the other workflow as an input parameter for its own run, or it can start a workflow
and let it continue its own run independently. Workflows can also start a workflow at a given time in the future,
or start multiple workflows simultaneously.
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Workflow Elements that Call Workflows on page 50
There are four ways to call other workflows from within a workflow. Each way of calling a workflow or
workflows is represented by a different workflow schema element.
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Call a Workflow Synchronously on page 52
Calling a workflow synchronously runs the called workflow as a part of the run of the calling workflow.
The calling workflow can use the called workflow's output parameters as input parameters when it runs
its subsequent schema elements.
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Call a Workflow Asynchronously on page 53
Calling a workflow asynchronously runs the called workflow independently of the calling workflow.
The calling workflow continues its run without waiting for the called workflow to complete.
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Schedule a Workflow on page 54
You can call a workflow from a workflow and schedule it to start at a later time and date.
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Call Several Workflows Simultaneously on page 55
Calling several workflows simultaneously runs the called workflows synchronously as part of the run
of the calling workflow. The calling workflow waits for all of the called workflows to complete before it
continues. The calling workflow can use the results of the called workflows as input parameters when
it runs its subsequent schema elements.
Workflow Elements that Call Workflows
There are four ways to call other workflows from within a workflow. Each way of calling a workflow or
workflows is represented by a different workflow schema element.
Synchronous Workflows
A workflow can start another workflow synchronously. The called workflow
runs as an integral part of the calling workflow's run, and runs in the same
memory space as the calling workflow. The calling workflow starts another
workflow, then waits until the end of the called workflow's run before it starts
running the next element in its schema. Usually, you call a workflow
synchronously because the calling workflow requires the output of the called
workflow as an input parameter for a subsequent schema element. For
example, a workflow can call the Start virtual machine and wait workflow to
start a virtual machine, and then obtain the IP address of this virtual machine
to pass to another element or to a user by email.
Asynchronous
Workflows
A workflow can start a workflow asynchronously. The calling workflow starts
another workflow, but the calling workflow immediately continues running
the next element in its schema, without waiting for the result of the called
workflow. The called workflows run with input parameters that the calling
workflow defines, but the lifecycle of the called workflow is independent from
the lifecycle of the calling workflow. Asynchronous workflows allow you to
create chains of workflows that pass input parameters from one workflow to
vCenter Orchestrator Developer's Guide
50 VMware, Inc.