Published: 16 Nov 2011
Only a small slice of cloud computing vendors can deliver a full stack of cloud options that are flexible, scalable and ready for the enterprise. Citrix’s cloud products allow enterprises to build out an infrastructure in the cloud and deliver it to the end user.
Using products in the Citrix Systems Inc.’s cloud suite, IT administrators can manage the hypervisor, desktop delivery, identity federation and user profiles. One advantage of building your private cloud using Citrix is that all components can be deployed as virtual instances. This means you can launch all of the components in a ready-to-go virtual environment that uses hardware located in a data center or hosting facility.
Step 1. Hypervisor configuration
Whether using a private or hosted server, you need to create a virtual environment to build out your cloud. After buying the hardware, you can install Citrix’s XenServer hypervisor. The following are key features in XenServer:
- High availability: With server pooling, workloads are kept in a redundant state and if a failure occurs virtual machines (VMs) are migrated automatically between hosts.
- Storage support: XenServer supports several different storage devices and can manage the devices directly at the graphical user interface and command line level.
- VM provisioning: Administrators can quickly deploy new VMs when peak usage requires it. They can also tie in a provisioning server to manage VM images.
Depending on the deployment, the hypervisor has several other features. When the hypervisor has been installed and is operational, you’ll need to attach storage for newly created images.
Step 2. Appliance authentication
The NetScaler appliance, offered as a virtual or physical server, is used for load balancing, application firewall or to secure an entry point. The choice between a physical or virtual device will depend on your traffic throughput requirements or need for a hardware component.
Because access to a cloud environment must be secure, you’ll also need a solid gateway. NetScaler’s appliance allows you to create load-balancing servers that can handle user connectivity.
Cloud environments also require high availability among sites; the NetScaler appliance provides this through its Global Server Load Balancing (GSLB). Having the ability to link multiple sites creates a more robust and stable cloud infrastructure.
Step 3. Application delivery
Once you’ve configured the hypervisor and entry point, you need an engine to house and deliver applications to the cloud. Citrix XenApp 6.5 is a robust application that delivers applications to end users. You can install XenApp on a physical or virtual Windows Server 2008 R2 64-bit instance for quick delivery. Then you can install applications, isolate them, manage user access through Active Directory (AD) and allow users to work seamlessly through the cloud.
User access is managed through XenApp’s Web interface. Authentication can occur on an instance of the Web Interface installed on the NetScaler or directly on the XenApp box. When logging into the cloud-facing portal, users enter their own AD credentials; based on their security group, they will be given access to a specific subset of applications. This portal can be accessed from any device at any location, as long as the user has a connection to the Internet.
Step 4. Desktop delivery
One of the biggest benefits of cloud computing for users is that they can launch their own corporate desktops from anywhere and on virtually any device. For example, a user can launch a Windows 7 corporate desktop from an iPad device, no matter where he is located. By centrally housing all master images and giving users access through the cloud, they can access corporate images via personal devices.
With technologies such as HDX, an improvement to the ICA protocol stack, administrators are able to improve the speed and quality of Flash movies and pages in hosted desktops, making the end-user experience seamless. XenDesktop delivers desktops as a pooled or dedicated environment in which users receive the first available desktop or a persistent one, respectively.
When a user launches his desktop from the cloud, he can also access personal applications that are actually housed on the XenApp server, which the user connects to when he signs into a desktop instance. To the user, it all looks seamless, as if the application was always available to the desktop. In reality, the process is separate and managed at the data center.
Step 5: Federated identity through Open Cloud Access
Many organizations are running Software as a Service (SaaS) applications in conjunction with a Citrix cloud environment. Problems can occur when users need to remember and enter multiple credentials to access different SaaS applications.
Citrix’s Open Cloud Access brings identity federation to the cloud. By extending AD into the cloud, Open Cloud Access can place SaaS icons, such as Salesforce or GoToMeeting, directly into the user’s portal. Then, using an existing set of AD credentials, users can log into SaaS applications without having to re-enter a username and password.
Step 6: Cloud delivery and management
Citrix’s recent acquisition of CloudStack takes cloud delivery to the next level. CloudStack is an open source cloud OS that’s similar to Amazon Elastic Cloud Compute (EC2), except CloudStack delivers public cloud using your own hardware. CloudStack orchestrates virtualized resources into one homogeneous environment where you can delegate the creation to various VMs through a self-service CloudStack portal.
CloudStack enables a secure multi-tenant cloud computing environment; with one click, you can deploy virtual servers from a predefined template. Virtualized instances can be turned off, paused and restarted via the Web interface, command line or by calling the extensive CloudStack application programming interface (API).
The product integrates with XenServer, allowing for greater manageability of a Citrix cloud environment. The console gives cloud administrators a view of the aggregate storage, IP pools, CPU, memory and other resources. Additionally, it lists events that occur in the cloud in chronological order, making it easy to track them.
With the addition of CloudStack, administrators can make better decisions on how to deliver the enterprise cloud. Cloud architects can dedicate an entire VLAN to a specific account for MPLS support between network nodes. Enterprises can also create a multi-role support environment that gives administrators access only to the tools that they need.
As cloud computing continues to evolve, so will its product base. Vendors will continue to develop powerful new tools that allow for a more seamless cloud delivery strategy and, most important, a more robust and positive end-user experience.
ABOUT THE AUTHOR:
Bill Kleyman, MBA, MISM, is an avid technologist with experience in network infrastructure management. His engineering work includes large virtualization deployments as well as business network design and implementation. Currently, he is a Virtualization Solutions Architect at MTM Technologies, a national IT consulting firm.