xendesktop interview

1.what is provisioning services?
 Citrix Provisioning Services™ uses streaming technology to dynamically deliver server workloads and desktop images on demand to any physical or virtual machine, reducing IT capital and operational costs while increasing business agility. 

2.what is single-sign-on?
Single sign-on (SSO)is a session/user authentication process that permits a user to enter one name and password in order to access multiple applications. The process authenticates the user for all the applications they have been given rights to and eliminates further prompts when they switch applications during a particular session.

3.what is catalog?what are different catalogs available?

A catalog is a collection of machines of the same type.The catalogs are 

                          1.pooled(random,static)

                          2.dedicated

                          3.existing

                          4.physical

                          5.streamed

4.what are catalogs available in xendesktop?

Choosing the Machine Type

The machine type defines the type of hosting infrastructure used for desktops and the level of control that users have over their desktop environment. This determines the usage scenarios for which the desktops are best suited. When deciding which machine type to use, consider the tasks that users will perform with their desktops and the devices to which the desktops will be delivered. The type and amount of infrastructure available to host each desktop is also an important consideration.

XenDesktop offers the following machine types:

Pooled

Pooled machines provide desktops that are allocated to users on a per-session, first-come first-served basis. Pooled-random machines are arbitrarily assigned to users at each logon and returned to the pool when they log off. Machines returned to the pool are available for other users to connect to. Alternatively, with pooled-static machines, users are assigned a specific machine from the pool when they first log on to XenDesktop. Users are connected to the same machines for all subsequent sessions. This allows users of pooled-static machines to be associated with specific VMs, which is a licensing requirement for some applications. Pooled desktops are freshly created from the master VM when users log on, although profile management can be used to apply users' personal settings to their desktops and applications. Any changes that users make to their desktops are stored for the duration of the session, but are discarded when users log off. Maintaining a single master VM in the data center dramatically reduces the time and effort required to update and upgrade users' desktops.

Your users:

• Are task workers who require standardized desktops, such as call center operators and retail workers
• Use shared workstations, for example students and faculty in educational institutions
• Do not need to or are not permitted to install applications on their desktops

You want to:

• Optimize hardware usage by providing only the number of desktops that are required at any one time rather than assigning each user a specific desktop
• Maintain control over desktops and increase security by preventing users from making permanent changes
• Minimize desktop management costs by providing a locked-down standardized environment for your users

Dedicated

Dedicated machines provide desktops that are assigned to individual users. Machines can be assigned manually or automatically assigned to the first user to connect to them. Whenever users request a desktop, they are always connected to the same machine, so you can allow users to personalize their desktops to suit their needs. Dedicated desktops are created from the master VM the first time that users log on, but all subsequent changes made to the desktops are persisted. As with traditional local desktops, changes and updates are permanent and must be managed on an individual basis or collectively using third-party electronic software distribution (ESD) tools. Changes made to desktops are stored in difference disks that expand as required, so storage space is used only as it is needed.

Your users:

• Are task or knowledge workers who require personalized desktops of which they can take ownership
• Are mobile workers who want to access the same desktop from a variety of devices over different networks
• Need to install their own applications on their desktops

You want to:

• Standardize certain aspects of users' desktops through the use of a common template
• Deliver users' desktops to any device regardless of hardware capability
• Reduce desktop management costs while still providing your users with a personalized desktop experience

Existing

The existing machine type enables you to use XenDesktop to manage and deliver user desktops that you have already migrated to VMs in the data center. As with traditional local desktops, changes and updates are permanent and must be managed on an individual basis or collectively using third-party electronic software distribution (ESD) tools. Managing your existing VM-based desktops through XenDesktop affords you greater control over their power states; for example, you can configure XenDesktop to shut down VMs when users log off to minimize unnecessary power consumption in the data center.

Your users:

• Already have VM-hosted desktops
• Have a large number of different and conflicting requirements for their desktops such that it is more efficient for you to prepare a bespoke desktop for each user than to create a common template that meets the needs of all users
• Need to install their own applications on their desktops

You want to:

• Use XenDesktop to manage and deliver existing desktops hosted on VMs in the data center
• Deliver individually tailored desktops to a small but heterogenous group of users
• Reduce support costs by centralizing user desktops in the data center without moving to a virtual desktop solution

Physical

The physical machine type enables you to use XenDesktop to manage user desktops hosted on dedicated blade PCs in the data center. As with traditional local desktops, changes and updates are permanent and must be managed on an individual basis or collectively using third-party ESD tools. Using blade PCs enables you to support small numbers of users who have particularly demanding performance requirements. This approach offers all the benefits of centralization, but ensures dedicated processing power for each user by hosting only one desktop per server.

Your users:

• Are technical workers or power users
• Use processor-intensive applications, such as financial modeling software
• Have high performance level expectations for line of business applications

You want to:

• Use XenDesktop to manage and deliver user environments that require dedicated specialist hardware
• Deploy dedicated hardware for power users so that they do not have to share server resources with other users
• Reduce support costs by centralizing complicated specialist systems in the data center

Streamed

The streamed machine type enables you to deliver desktops to VMs and blade PCs that have been configured to load the operating system over the network from Provisioning services. Target devices are managed in Provisioning services as a device collection and the desktops are delivered from a Provisioning services vDisk imaged from a master target device. Using Provisioning services to deliver desktops enables you to leverage the processing power of existing hardware, while realizing all the benefits of centralized desktop management. This approach offers an entry point to desktop virtualization using existing resources and reducing the need for additional storage capacity in the data center.

Your users:

• Are task or knowledge workers who require either standardized desktops or individual desktops of which they can take ownership
• Use shared workstations, for example students and faculty in educational institutions
• Use locked-down workstations to access secure data, for example government employees

You want to:

• Deliver desktops to device collections containing mixtures of different types of PC hardware
• Maximize data security by delivering desktops to diskless target devices
• Virtualize desktops using existing hardware and without adding more storage in the data cente