Centralis^® Centinel 1.3

Free software enabling safer reboots for Citrix servers, updated based on customer feedback to support the use of scripts and a "Retry" facility to keep re-checking the server

Overview

In Citrix environments which are available to users 24 hours a day, 7 days a week, it is often difficult for administrators to perform regular reboots of the Citrix Servers to relieve instability issues caused by application memory leaks.

Scheduled reboots are fine, but potentially one or more Citrix Servers will have users logged in, and therefore can’t be safely rebooted.

Centralis Centinel gives administrators the ability to check prior to a reboot whether users are logged into each Citrix Server. Only if there are no users logged into the Citrix Server will the reboot be performed.

The latest version also allows a script to be run prior to the reboot, and also for Centinel to retry after a fixed number of times at minute intervals to test whether any remaining users have logged out.

How it works

Centralis Centinel is a pure Win32 application and requires no additional DLL’s. It uses the Windows Terminal Server API and can therefore be used on either Terminal Server or Citrix MetaFrame / Presentation Servers.

When executed, it will check the number of currently logged on users. If no users are currently logged onto the server, the server will be rebooted. If any users are logged onto the Server, then the server will not be rebooted. "Console" Sessions do NOT count as a logged-in user and will be ignored.

The different session states monitored are Active, Connected, ConnectQuery, Shadow, Disconnected, Idle, Listen, Reset, Down and Init. If the session type is either Idle, Listen or Down it is ignored.

Using Centralis Centinel

Centinel should be run as a scheduled task. Simply copy the file into a directory which is in the System Path (defined by the PATH variable) and schedule the application to run when you wish to reboot the server (and the most likely time when no users are expected to be logged on to the server). The command line arguments for the application are shown below.

The success or failure of a reboot is reported in the NT Event Log.

Platforms

• Centralis Centinel is designed to run on Windows 2000 Server and Windows 2003 Server with Terminal Services enabled
• Citrix optional on both operating system platforms

Options

Centralis Centinel supports the following command line switches:

• -? display command line help
• -d ignore disconnected session
• -v verbose mode
•  -l script.cmd launch a script (e.g. .bat, .cmd, etc) file prior to rebooting a server. Centinel will wait for the script to execute before rebooting
•  -r retries Number of times (in minutes) to retry if users are logged in. The number of retries must be specified as there is no default setting.

Example command line:

centinel.exe -d -l myscript.cmd -r 5 : ignore disconnected session. If users are connected, retry 5 times (once every minute). If all users disconnect within the five tries, execute script.cmd then reboot the server.

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