If you have XenServer up and running, you may have noticed that some virtualization features in XenCenter are disabled. Select, for example, the Pool > High Availability option, and you'll get a message that you need Citrix Essentials for this function.
To find out whether you like Citrix Essentials, you can try it before you buy it. The Citrix website downloads page offers one-month evaluation versions for free. After filling in your personal details, you can download the software immediately. Here's how to get the most out of your Citrix Essentials trial.
But first, a side note: Citrix Essentials doesn't exist just for XenServer. You can also use it to manage Microsoft Hyper-V, and all the functionality discussed in this article applies to both platforms. As an additional virtualization feature on Hyper-V, Citrix Essentials offers site replication for disaster recovery.
Citrix Essentials components
To start, you need to install the various Citrix Essentials components. In the Citrix Essentials Platinum Edition trial, you'll find various programs. The first is the Citrix license server, which is used to manage licenses for your different Citrix products. The license server is available for Windows platforms as well as for Unix, but you do need a server -- physical or virtual -- to run it.
Then there is the high availability and workload balancing component, which ensures that virtual machines (VMs) restart on another host in case of a failure. With workload balancing, Citrix Essentials also tries to automatically load balance VMs in your environment.
If you need more advanced, automated management of resources, you'll need StorageLink and Provisioning Services. StorageLink allows you to take advantage of all the resources and functionality of your storage systems. And with Provisioning Services, you can provision VMs from a single master image.
Next, there is Automated Lab Management, which automatically builds lab and training environments based on the settings you provide. There is also Stage Management, with which you can streamline the building, testing, sharing and delivering of applications on demand into production environments. And finally, there is Workflow Studio, which allows you to customize the automation of key management processes.
Managing the Citrix Essentials virtualization features
To get the most from Citrix Essentials, you also need a standalone management environment, which you can create by installing a specific server. This management environment may be any flavor of Unix Linux or Windows, but the integration with Windows offers more advanced features, so it is probably your best choice. A Windows management environment also allows you to benefit from the Active Directory integration in XenServer 5.5.
After setting up the management environment, you can download and install the components you need. This installation process is not that hard. Just run the installer and follow the prompts to get your components in the right environment.
In addition, you need a license file for each product discussed above. After installing the license file, you'll have full access to all of the functionality for a period of 30 days. So ensure that you have enough time when you start testing the software, because there are a lot of virtualization features to explore.
Sander van Vugt is an independent trainer and consultant based in the Netherlands. Van Vugt is an expert in Linux high availability, virtualization and performance and has completed several projects that implement all three. He is also the writer of various Linux-related books, such as Beginning the Linux Command Line, Beginning Ubuntu Server Administration and Pro Ubuntu Server Administration.