Chapter 11. Working With Virtual Machines

11.2.1. Monitor VMs for Max Capacity

The CloudPlatform administrator should monitor the total number of VM instances in each cluster, and disable allocation to the cluster if the total is approaching the maximum that the hypervisor can handle. Be sure to leave a safety margin to allow for the possibility of one or more hosts failing, which would increase the VM load on the other hosts as the VMs are automatically redeployed. Consult the documentation for your chosen hypervisor to find the maximum permitted number of VMs per host, then use CloudPlatform global configuration settings to set this as the default limit. Monitor the VM activity in each cluster at all times. Keep the total number of VMs below a safe level that allows for the occasional host failure. For example, if there are N hosts in the cluster, and you want to allow for one host in the cluster to be down at any given time, the total number of VM instances you can permit in the cluster is at most (N-1) * (per-host-limit). Once a cluster reaches this number of VMs, use the CloudPlatform UI to disable allocation of more VMs to the cluster.

11.2.2. Install Required Tools and Drivers

Be sure the following are installed on each VM:

•For XenServer, install PV drivers and Xen tools on each VM. This will enable live migration and clean guest shutdown. Xen tools are required in order for dynamic CPU and RAM scaling to work.

•For vSphere, install VMware Tools on each VM. This will enable console view to work properly. VMware Tools are required in order for dynamic CPU and RAM scaling to work.

To be sure that Xen tools or VMware Tools is installed, use one of the following techniques:

•Create each VM from a template that already has the tools installed; or,

•When registering a new template, the administrator or user can indicate whether tools are installed on the template. This can be done through the UI or using the updateTemplate API; or,

•If a user deploys a virtual machine with a template that does not have Xen tools or VMware Tools, and later installs the tools on the VM, then the user can inform CloudPlatform using the updateVirtualMachine API. After installing the tools and updating the virtual machine, stop and start the VM.

11.3. VM Lifecycle

Virtual machines can be in the following states:

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Citrix Systems 4.2 manual VM Lifecycle, Monitor VMs for Max Capacity, Install Required Tools and Drivers
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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.
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