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CloudStack Reference Architecture


The following document will explain the technical details and steps for configuring a cloud's underlying infrastructure and network architecture. 

For detailed how-to instructions on how to build a CloudStack cloud, see Installing CloudStack. This document references the CloudStack Acton release.


  • To enable security groups, elastic load balancing, and elastic IP on XenServer, download and install the CloudStack XenServer Support Package (CSP) in the CloudStack Installation Guide.

Note: RHEL licenses are not currently available for running instances on XenServer hypervisors. However, if it is absolutely necessary, then you can utilize a cluster running RedHat KVM hypervisor for all instances which must run RHEL.

Infrastructure Architecture

The following diagram highlights some of the key components of a cloud's infrastructure. Each cloud will be unique because of the wide range of configuration options. A cloud's underlying architecture can be relatively simple or extremely complex. At a minimum, a cloud must have the following components in order to be properly supported by the RightScale management platform.



Firewall and Switch

CloudStack assumes InterVLAN Routing will be present between CloudStack components. Use Layer-3 Switches. A firewall is technically optional, but strongly recommended. 

  • (1) 24-48 Port Layer-3 Switch

Cloud Management Server

See the CloudStack Architectural Components for an architecture diagram (via CloudStack Installation Guide).

The Cloud Management Server (CMS) serves as the Cloud's API endpoint. All requests for cloud resources will be made to the CMS. The CMS must be configured to accept requests from RightScale services.

  • Use the latest version of the CloudStack 3.x Management Server software (recommended) 
  • All-in-one Cloudstack server installation
    • CentOS or RHEL 6.2+
    • Integrated MySQL 5.1 (or greater) database (required for master only)
  • If you are using more than one management server for redundancy purposes, you will need to have a load balancing service above the cloud management servers.

Compute Nodes

Compute nodes can be configured in a wide variety of system architectures. The compute node runs the virtualization technology and handles the processing. At a minimum, you will need to have at least one of each type.

  • Zone/Datacenter - An aggregated endpoint for accessing hosts. Each zone/datacenter can consist of one or more pods and primary storage.
  • Pod - A pod is typically a dedicated rack of hardware. Each pod can consist of one or more clusters.
  • Cluster - A cluster consists of one or more hosts and primary storage. Each cluster can consist of one or more nodes.
  • Host/Node - A host is a single compute node that can consist of one or more virtual machines (i.e. instances).
  • Instances/VMs - A host/node can be configured to have one or more instances or virtual machines (VMs). Each instance will have an ID, IP address, etc. 

CloudStack Supported Cluster Sizes

  • Citrix XenServer: up to 8 Hosts per Cluster
  • VMware vSphere: 8 Hosts per Cluster
  • KVM: up to 16 hosts per Cluster

Cloud Storage

A basic cloud configuration can consist of a single NFS server (CentOS 5.4+ OS) that provides both primary and secondary storage. 

  • Primary Storage - Used for block-level, volume-based storage on instances. 
  • Secondary Storage - Used for storing volume-based backups called snapshots. Images are also stored. 100GB minimum capacity.


Defined configuration sizes (in GB) for attaching block devices to an instance. For example, 1GB (minimum), 2GB, 3GB...100GB (maximum).


Upload base RightImages to the cloud that can be used to launch instances in the cloud. You can either upload RightImages that are built by RightScale or build and upload your own RightScale-enabled images. Please contact account manager at RightScale for details.


Although CloudStack supports enterprise-grade hypervisors such as VMware vSphere, Oracle VM, and Citrix XenServer, RightScale currently only supports the following hypervisors in the dashboard and API:

  • XenServer (recommended)
  • KVM 
  • vSphere 

Cloud Configurations

  • Basic Networking Mode (recommended)
  • Defined Zones
  • Defined Subnets
  • Primary and Secondary Storage (Block-level storage with backup (snapshot) support)
  • Access to user data and metadata
  • Hypervisor Support
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Last modified
21:41, 16 May 2013



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