XenApp administrators often encounter a situation which requires to take the XenApp Server “offline” to be troubleshooted. By “offline”, it means the server should not take any more new sessions while keep the existing session untouched.
Usually the administrator will use either the script or AMC to disable the logon of the server so no more sessions can be launched against that server. But disable logon also disable the capability of the remote login to the server to troubleshoot even using RDP protocol.
What and why Citrix? Citrix is a serverbased computing package that incorporates a proprietary network protocol that separates an application’s logic from its user interface allowing clients to run “thin.” Thin clients have little or no secondary storage and are used only as clients depending on the server for software, processing and secondary storage. The proprietary network protocol that allows users to use Citrix technology is the Independent Computing Architecture (ICA).
Prerequisites Explained:
We all know the prerequisites for installing Citrix Xenapp(any version). But if anyone asks us WHY they are considered as prerequisites, why they are important to Citrix? Most of us dont have answer(including me). Hence I am going to explain some of the important prerequisites here:
If we are talking about prerequisites only 3 major roles comes into picture as stated below:
Terminal Services(Remote Desktop Services). Web Server(IIS). Application Server.
Prerequisites for installing Citrix Xenapp 5.0
You will be installing the following XenApp 5 software components:
License Server License Management Console XenApp 5.0 for Windows Server 2008 (32-bit) Access Management Console XenApp Advanced Configuration Data Store Database Web Interface Many of the required Server 2008 Roles and Features are the same for the various XenApp software components. To summarize the Checklist document, you will need the following Roles installed:
Application Server (Add Required Features) Terminal Services Web Server (IIS) The following Role Services need to be installed:
_In general below mentioned are the prerequisites and a brief explanation is given in the below article: .net 3.5 application server role remote desktop services role Web server(IIS along with selected roles) microsoft windows installer group policy management console microsoft visual C++ binaries
System Requirements for XenApp 6 for Windows Server 2008 R2
System requirements for XenApp features and related technologies are described in their respective System Requirements documentation; that includes plug-ins and agents, Web Interface, Single Sign-on, Service Monitoring, EdgeSight, SmartAuditor, Application Session Recording, Provisioning Services, and Power and Capacity Management.
Click Here to download the upgrade utility.
XenApp 6.5 does not provide a binary upgrade path from XenApp 6.0. For some environments, the ability to create a new virtual machine image or clean installation XenApp 6.5 servers might not be possible.
The script performs what normally would be a long process of manually uninstalling XenApp 6.0 components in a select order, then installing XenApp 6.5. The following steps are performed:
System Requirements for XenApp 6.5
System requirements for the XenApp server role and the Citrix AppCenter are described below. System requirements for other XenApp features, components, and related technologies are described in their respective system requirements documentation; that includes receivers, plug-ins and agents, Web Interface, Single Sign-on, Service Monitoring, EdgeSight, SmartAuditor, Application Session Recording, Provisioning Services, and Power and Capacity Management.
To ensure the availability of XenApp 6.5 features and correct operation:
On-demand application delivery with Citrix XenApp How application virtualization and session virtualization work
Citrix XenApp is an on-demand application delivery solution that comprises application virtualization and session virtualization technologies.
Understanding application virtualization Citrix application virtualization technology isolates applications from the underlying operating system and from other applications to increase compatibility and manageability. As a modern application delivery solution, XenApp virtualizes applications via integrated application streaming and isolation technology. This application virtualization technology enables applications to be streamed from a centralized location into an isolation environment on the target device where they will execute.
General Info:
Sharing resources from one physical box(like esx, xenserver, hyper v etc) is server virtualization.
Publishing virtual machines created by xenserver, esx etc to end users is desktop virtualization.
Xenconvert is used for converting physical machine to VM.
Multiple OS boots from single VHD file using provisioning services(PVS).
ICA and RDP Differences: 1. RDP works only under TCP/IP, while ICA works on many protocols.
2. RDP doesn’t permit applications to run in a browser, while works for ICA
Below is a list of technical specifications and platform requirements for XenServer.
Infrastructure XenServer Host 64-bit x86 server-class system CPU: 1.5 GHz minimum, 2 GHz or faster multi-core recommended Intel® VT or AMD-V™ required for support of Windows guests 2GB to 1TB physical memory Up to 64 logical processors 100Mb/s or faster NIC Up to 16 physical NICs Local, Fibre Channel or SAN boot disk with 16 GB of space minimum, 60 GB or more recommended Fibre Channel, iSCSI or NFS LUN with 356MB of space minimum for High Availability (HA) heartbeat storage repository XenCenter Client x86-based system Microsoft® Windows® 2000, Windows XP, Windows Server® 2003, Windows Server 2008, Windows Vista , or Windows 7 (all Editions and Versions) .
