vRealize Automation- vCAC Introduction

What is vCloud Automation Center?

vCloud Automation Center (vCAC) is part of vCloud suite (Enterprise Edition) which provides administrators with the ability to provision and configure storage, network and compute resources across multiple platforms.

It makes life of a cloud administrator easier by allowing them to automate application delivery and simplify the deployment of multi-tiered applications while managing multi-vendor and multi-cloud infrastructures.

VMware offers vCloud Automation Center in three editions: Standard, Advanced and Enterprise.

The goal of vCAC is to deploy and provision cloud services across private & public clouds, physical infrastructures, hypervisors and public cloud providers. The following cloud Platforms are supported by vCAC:

1: vCloud Director (as of version 5.1)

2: Hyper-V

3: XenServer

vCAC also supports Dell DRAC, HP ILO, Cisco’s UCS manager and there’s an integration with NetApp DataOntap.

vCAC Architecture                                       

The architecture of vCAC looks like below

vcac arch

Graphic Thanks to VMware

At the very high level, vCAC architecture can be broken down into following tiers:

  • Presentation Tier– The uppermost tier provides an interface to the end-users/consumers who access resources and applications provisioned from the Cloud.  This access is provided via a self-service web portal that allows users to request resources from a catalog of services.
  • Policy Tier– This tier provides the policies and governance which dictate what and how consumers can access requested resources.
  • Resource Tier– Physical and virtual resources provisioned from the underlying infrastructure are assigned to reservation pools (Cloud Blueprints and Resource Reservations) and prepared for consumption, in compliance with customized business and IT policies.
  • Infrastructure Orchestration Tier– The bottom tier orchestrates the provisioning of the underlying resources for a customer’s Hybrid Cloud.  These resources can be physical infrastructure, virtual data center, or a Public Cloud.

vCAC Components

A vCAC environment can be divided into 3 parts:

1: vCAC core: vCAC core part contains the following sub-components:

Web Server:

There are three different webs services that can either be installed together on the same webserver or installed separately. The vCAC web services are designed to run on Microsoft IIS  Web Server.

a) Administration Portal Web Site: The Administration portal provides the administration user interface to vCAC and communicates directly with the Model Manager.

b) Reports Web Site: The reports web site provides access to vCAC reports.

c) Model Manager Web Services: The Model Manager manages core vCAC and custom models. The Model Manager provides services and utilities for persisting, versioning, securing and distributing the different elements of the model and for communicating with the vCAC portal website and Distributed Execution Managers (DEMs).

2: vCAC server

The vCloud Automation Center service is also known as Manager Service and has primary function of coordinating communication between vCAC agents, vCAC database, Active Directory and SMTP server. The Manager Service communicates with the portal website through the Model Manager.

The system where Manager Service is installed is known as vCAC Server.

3: SQL Server

Like any other VMware product, vCAC also requires a Microsoft SQL Server database to maintain information about the pieces of infrastructure which it manages and its own elements and policies. Again we have option to use either embedded or external database to use with vCAC.

4: Distributed Execution Manager

DEM’s are responsible for coordinating and executing the requested workflows. The two types of DEMs are the Orchestrator and the Worker. The Worker DEM is responsible for executing the requested workflows. The Orchestrator is responsible for pre-processing and scheduling the workflows on all available Worker DEMs

5: vCAC Agent

vCAC agents are used to interact with external system. There are different types of agents, each having specific functions.  There are agents that interact with hypervisors, agents that allow vCAC to run scripts in guests OS during provisioning process, agents that interact with virtual desktop solutions or WMI agents that enable vCAC to collect data from Windows machines.

6: vCenter Orchestrator

vCO integrates with vCloud Automation Center to extend the business process automation capabilities of your cloud infrastructure. The standard master workflow in vCloud Automation Center can be extended to call vCenter Orchestrator workflows that communicate with external systems or perform external processes.

Upon approval, a work order is generated against an external management system. At the time of provisioning, a custom script is executed and CMDB is updated to reflect the new machine. After provisioning, the machine can be backed up or changed. That change in the machine requires an update to the CMDB. The CMDB is updated once again when the machine is not needed, put into retirement, and subsequently archived.

For a newbie like me the architecture of vCAC seems  a bit complex and can be understand when we start exploring it more and more. A simple reference to vCAC architecture can be laid out as below

vcac arch2

When I was discussing about vCAC with one of my friend who has experience in deploying vCAC into his production environment, he suggested me that vCAC is replacement of vCloud Director as it is end of life and is used for building private cloud for your organization.

This is true to some extent not completely. Yes vCAC can be used to built private clouds but it can be integrated with existing vCloud director instances. Lets see how it is.

vCAC and vCloud Director Integration

The integration of vCD with vCAC primarily resides within the Resource Tier. vCAC can discover vDC and vApp resources and import them into its reservations pools; it ckan also import vApp catalogs created in vCD and expose them to consumers as vCAC virtual blueprints that can be requested.

They key here is to understand that vCD is providing the resource pools on top of which vCAC can build out vSphere-based services to be consumed via their self-service portal. vCAC resource pools can also be created from non-vSphere resources, such as non-virtualized operating systems, other hypervisors, or Public Clouds, by leveraging those specific resources’ available tools.

See the below screenshot which will give you an idea how the two components are integrated together.


One of the biggest weaknesses of vCD is that the web portal is not as customizable as most users would like and it lacks the ability to apply a variety of business policies and governance to its resources. Also there is no orchestration and workflow capabilities available in vCD for automating the provisioning of virtual and physical infrastructure.

With the introduction of vCAC, these capabilities that are lacking in vCD can now be handed off to vCAC.  In the new vCloud Suite 5.1, vCAC  focuses on the presentation and policy tiers and leverages vCenter Orchestrator (vCO) to automate the provisioning of the underlying infrastructure.

How vCloud Director constructs map to vCloud Automation Center

While searching for how vCAC and vCloud Director ties together, I came across a very cool graphic on David Hill’s Site which I am using here. It helps understand how the pieces in vCloud is mapped to corresponding vCAC


Graphic Thanks to Davidhill.co

I hope this post is informational to you. In the next post of this series we will see vCAC in action. Stay Tuned!!!