The vRealize Automation IaaS Manager Service and Distributed Execution Management (DEM) server orchestrate the provisioning of workloads in the vRealize Automation IaaS platform. They use the IaaS proxy agents which provision the workloads on a hypervisor endpoint and synchronize data about an endpoint with the vRealize Automation database

IaaS Manager Service

  • Manages the integration of vRealize Automation IaaS with external systems and databases.

  • Provides business logic to the DEMs.

  • Manages business logic and execution policies.

  • Maintains all workflows and their supporting constructs.

DEM Orchestrator and DEM Worker

A Distributed Execution Manager (DEM) runs the business logic of custom models by interacting with other vRealize Automation (repository) as required.

Each DEM instance acts in either an orchestrator role or a worker role.

  • The DEM orchestrator monitors the status of the DEM workers. If a DEM worker stops or loses the connection to the Model Manager or repository, the DEM orchestrator puts the workflow back in the queue. It manages the scheduled workflows by creating new workflow instances at the scheduled time and allows only one instance of a particular scheduled workflow to run at a given time. It also preprocesses workflows before execution. Preprocessing includes checking preconditions for workflows and creating the workflow's execution history.

  • DEM workers are responsible for executing provisioning and deprovisioning tasks initiated by the vRealize Automation portal. DEM workers also communicate with specific infrastructure endpoints.

IaaS Proxy Agent

The vRealize Automation IaaS Proxy Agent is a Windows service that communicates with specific infrastructure endpoints. In this design, you use the vSphere Proxy Agent to communicate with vCenter Server.

The IaaS Proxy Agent server provides the following functions:

  • Interacts with different types of infrastructure components. This design uses only the vSphere Proxy Agent.

  • vRealize Automation does not itself virtualize resources, but works with vSphere to provision and manage the virtual machines. It uses vSphere Proxy Agents to send commands to and collect data from vSphere.

The vRealize Automation IaaS Manager, DEM Orchestrator, DEM Worker and IaaS Proxy Agent are separate components, but in this design, you install them on the same virtual machine.

Table 1. Design Decisions About vRealize Automation IaaS Model Manager and DEM Orchestrator Server

Decision ID

Design Decision

Design Justification

Design Implication


Deploy one virtual machine to run the vRealize Automation Manager Service, the DEM Orchestrator, the DEM Worker, and IaaS Proxy Agent services.

  • Co-locating the Manager service, DEM Orchestrator, DEM Worker and the IaaS Proxy Agent on a single VM provides the minimal footprint that is required for the consolidated cluster.

  • This design also provides for future expansion of the CMP to provide full application level HA.

Relies on vSphere HA for high availability of the application.

Table 2. Resource Requirements for the Shared Virtual Machine of vRealize Automation IaaS Model Manager, DEM and IaaS Proxy Agent



Number of vCPUs



8 GB

Number of vNIC ports


Number of local drives


vRealize Automation functions

Manager Service, DEM Orchestrator, DEM Worker, and IaaS Proxy Agent

Operating system

Microsoft Windows Server 2012 SP2 R2