7.1

Manager Service
The Manager Service is a Windows service that coordinates communication between IaaS Distributed
Execution Managers, the database, agents, proxy agents, and SMTP.
Your IaaS deployment requires that only one Windows machine actively run the Manager Service. For
backup or high availability, you may deploy additional Windows machines where you manually start the
Manager Service if the active service stops.
I Simultaneously running an active Manager Service on multiple IaaS Windows servers makes
vRealize Automation unusable.
The Manager Service communicates with the IaaS Web site through the Model Manager and must be run
under a domain account with administrator privileges on all IaaS Windows machines.
IaaS Database
The IaaS component of vRealize Automation uses a Microsoft SQL Server database to maintain information
about the machines it manages and its own elements and policies. Typically, the database is created for you
during installation. However, a system administrator can create the database separately as well.
Distributed Execution Managers
A Distributed Execution Manager (DEM) runs the business logic of custom models, interacting with the
database and with external databases and systems as required.
Each DEM instance acts in either a Worker role or in an Orchestrator role. The Worker role is responsible for
running workows. The Orchestrator role is responsible for monitoring DEM Worker instances,
preprocessing workows to run, and scheduling workows.
The DEM Orchestrator performs these specic tasks.
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Monitors the status of DEM Workers and ensures that if a Worker instance stops or loses its connection
to the Model Manager, its workows are put back in the queue for another DEM Worker to pick up.
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Manages scheduled workows by creating new workow instances at the scheduled time.
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Ensures that only one instance of a particular scheduled workow is running at a given time.
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Preprocesses workows before they are run, including checking preconditions for workows, used in
the implementation of the RunOneOnly feature, and creating the workow execution history.
One DEM Orchestrator instance is designated as the active Orchestrator that performs these tasks. Because
the DEM Orchestrator is essential to run workows, install at least one additional Orchestrator instance on a
separate machine for redundancy. The Orchestrator is automatically installed on the machine that also runs
the Manager Service. The additional DEM Orchestrator monitors the status of the active Orchestrator so that
it can take over if the active Orchestrator goes oine.
vRealize Automation Agents
vRealize Automation uses agents to integrate with external systems and to manage information among
vRealize Automation components.
You generally install the vSphere agent as part of a deployment. You can install additional agents according
to your site's requirements.
Installing vRealize Automation
16 VMware, Inc.