Chapter 11. Working With Virtual Machines

with previous versions will not have the dynamic scaling capability unless you update them using the following procedure.

11.11.2. Updating Existing VMs

If you are upgrading from a previous version of CloudPlatform, and you want your existing VMs created with previous versions to have the dynamic scaling capability, update the VMs using the following steps:

1.Make sure the zone-level setting enable.dynamic.scale.vm is set to true. In the left navigation bar of the CloudPlatform UI, click Infrastructure, then click Zones, click the zone you want, and click the Settings tab.

2.Install Xen tools (for XenServer hosts) or VMware Tools (for VMware hosts) on each VM if they are not already installed.

3.Stop the VM.

4.Click the Edit button.

5.Click the Dynamically Scalable checkbox.

6.Click Apply.

7.Restart the VM.

11.11.3. Configuring Dynamic CPU and RAM Scaling

To configure this feature, use the following new global configuration variables:

•enable.dynamic.scale.vm: Set to True to enable the feature. By default, the feature is turned off.

•scale.retry: How many times to attempt the scaling operation. Default = 2.

11.11.4. How to Dynamically Scale CPU and RAM

To modify the CPU and/or RAM capacity of a virtual machine, you need to change the compute offering of the VM to a new compute offering that has the desired CPU and RAM values. You can use the same steps described above in Section 11.11, “Changing the Service Offering for a VM”, but skip the step where you stop the virtual machine. Of course, you might have to create a new compute offering first.

When you submit a dynamic scaling request, the resources will be scaled up on the current host if possible. If the host does not have enough resources, the VM will be live migrated to another host in the same cluster. If there is no host in the cluster that can fulfill the requested level of CPU and RAM, the scaling operation will fail. The VM will continue to run as it was before.

11.11.5. Limitations

•You can not do dynamic scaling for system VMs on XenServer.

•CloudPlatform will not check to be sure that the new CPU and RAM levels are compatible with the OS running on the VM.

2http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1012764

96

Page 105 Page 107
Page 106
Image 106
Citrix Systems 4.2 Updating Existing VMs, Configuring Dynamic CPU and RAM Scaling, How to Dynamically Scale CPU and RAM
Page 105 Page 107

4.2 specifications

Citrix Systems, a leading provider of virtualization solutions and cloud computing technologies, released version 4.2 of its popular software, Citrix XenApp, which was previously known as Presentation Server. This version marked a significant evolution in providing users with remote access to applications and desktops, emphasizing simplicity, performance, and security.

One of the standout features of Citrix XenApp 4.2 is its improved application streaming capabilities. This technology allows applications to be delivered to users in real-time, reducing the need for extensive local installations and enhancing the user experience. With application streaming, administrators can efficiently manage applications on a central server while ensuring that users have immediate access to the necessary tools.

Another highlight of this version is the enhanced security measures put in place to protect sensitive data. Citrix XenApp 4.2 includes support for SSL encryption, providing a secure communication channel for data transmitted between the server and clients. This is particularly crucial for businesses that need to comply with strict data protection regulations. Additionally, the integration of endpoint security features ensures that unauthorized access to applications is minimized.

Performance enhancements are also a critical focus in this release. Citrix optimized the delivery of applications over various network conditions, ensuring that users experience minimal latency regardless of their location. This was achieved through the incorporation of SmartAccess and SmartControl technologies, which allow administrators to set policies based on user roles, device types, and network conditions. This level of granularity enables organization-wide security without compromising on usability.

The user experience was further improved with a revamped interface, making it easier for end-users to access their applications and data. Simplified menus, clear navigation paths, and the ability to customize user settings contributed to a more efficient workflow, allowing users to focus on their tasks rather than struggling with the software.

Finally, Citrix XenApp 4.2 was designed to be highly scalable. Organizations of all sizes could deploy this solution to deliver applications efficiently, adapting to their specific needs as their user base grows or changes. This flexibility is crucial for businesses looking to future-proof their IT investments while maintaining optimal performance.

In summary, Citrix XenApp 4.2 stands out with its enhanced application streaming, robust security features, improved performance under varying conditions, user-friendly interface, and scalability, making it an ideal choice for organizations seeking to leverage virtualization for remote access to applications and desktops.
Top Page Image Contents