Chapter 12.

Working With Hosts

12.1. Adding Hosts

Additional hosts can be added at any time to provide more capacity for guest VMs. For requirements

and instructions, see Section 8.6, “Adding a Host”.

12.2.Scheduled Maintenance and Maintenance Mode for Hosts

You can place a host into maintenance mode. When maintenance mode is activated, the host becomes unavailable to receive new guest VMs, and the guest VMs already running on the host are seamlessly migrated to another host not in maintenance mode. This migration uses live migration technology and does not interrupt the execution of the guest.

12.2.1. vCenter and Maintenance Mode

To enter maintenance mode on a vCenter host, both vCenter and CloudPlatform must be used in concert. CloudPlatform and vCenter have separate maintenance modes that work closely together.

1.Place the host into CloudPlatform's "scheduled maintenance" mode. This does not invoke the vCenter maintenance mode, but only causes VMs to be migrated off the host

When the CloudPlatform maintenance mode is requested, the host first moves into the Prepare for Maintenance state. In this state it cannot be the target of new guest VM starts. Then all VMs will be migrated off the server. Live migration will be used to move VMs off the host. This allows the guests to be migrated to other hosts with no disruption to the guests. After this migration is completed, the host will enter the Ready for Maintenance mode.

2.Wait for the "Ready for Maintenance" indicator to appear in the UI.

3.Now use vCenter to perform whatever actions are necessary to maintain the host. During this time, the host cannot be the target of new VM allocations.

4.When the maintenance tasks are complete, take the host out of maintenance mode as follows:

a.First use vCenter to exit the vCenter maintenance mode. This makes the host ready for CloudPlatform to reactivate it.

b.Then use CloudPlatform's administrator UI to cancel the CloudPlatform maintenance mode.

When the host comes back online, the VMs that were migrated off of it are migrated back to it and new VMs can be added.

12.2.2. XenServer and Maintenance Mode

For XenServer, you can take a server offline temporarily by using the Maintenance Mode feature in XenCenter. When you place a server into Maintenance Mode, all running VMs are automatically migrated from it to another host in the same pool. If the server is the pool master, a new master will also be selected for the pool. While a server is Maintenance Mode, you cannot create or start any VMs on it.

To place a server in Maintenance Mode:

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Citrix Systems 4.2 manual Working With Hosts, Adding Hosts, Scheduled Maintenance and Maintenance Mode for Hosts

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.