NSSM: The Non-Sucking Service Manager Version 2.9, 2011-02-28 NSSM is a service helper program similar to srvany and cygrunsrv. It can start any application as an NT service and will restart the service if it fails for any reason. NSSM also has a graphical service installer and remover. Full documentation can be found online at http://iain.cx/src/nssm/ Since version 2.0, the GUI can be bypassed by entering all appropriate options on the command line. Since version 2.1, NSSM can be compiled for x64 platforms. Thanks Benjamin Mayrargue. Since version 2.2, NSSM can be configured to take different actions based on the exit code of the managed application. Since version 2.3, NSSM logs to the Windows event log more elegantly. Since version 2.5, NSSM respects environment variables in its parameters. Since version 2.8, NSSM tries harder to shut down the managed application gracefully and throttles restart attempts if the application doesn't run for a minimum amount of time. Usage ----- In the usage notes below, arguments to the program may be written in angle brackets and/or square brackets. means you must insert the appropriate string and [] means the string is optional. See the examples below... Installation using the GUI -------------------------- To install a service, run nssm install You will be prompted to enter the full path to the application you wish to run and any command line options to pass to that application. Use the system service manager (services.msc) to control advanced service properties such as startup method and desktop interaction. NSSM may support these options at a later time... Installation using the command line ----------------------------------- To install a service, run nssm install [] NSSM will then attempt to install a service which runs the named application with the given options (if you specified any). Don't forget to enclose paths in "quotes" if they contain spaces! Managing the service -------------------- NSSM will launch the application listed in the registry when you send it a start signal and will terminate it when you send a stop signal. So far, so much like srvany. But NSSM is the Non-Sucking service manager and can take action if/when the application dies. With no configuration from you, NSSM will try to restart itself if it notices that the application died but you didn't send it a stop signal. NSSM will keep trying, pausing between each attempt, until the service is successfully started or you send it a stop signal. NSSM will pause an increasingly longer time between subsequent restart attempts if the service fails to start in a timely manner, up to a maximum of four minutes. This is so it does not consume an excessive amount of CPU time trying to start a failed application over and over again. If you identify the cause of the failure and don't want to wait you can use the Windows service console (where the service will be shown in Paused state) to send a continue signal to NSSM and it will retry within a few seconds. By default, NSSM defines "a timely manner" to be within 1500 milliseconds. You can change the threshold for the service by setting the number of milliseconds as a REG_DWORD value in the registry at HKLM\SYSTEM\CurrentControlSet\Services\\Parameters\AppThrottle. NSSM will look in the registry under HKLM\SYSTEM\CurrentControlSet\Services\\Parameters\AppExit for string (REG_EXPAND_SZ) values corresponding to the exit code of the application. If the application exited with code 1, for instance, NSSM will look for a string value under AppExit called "1" or, if it does not find it, will fall back to the AppExit (Default) value. You can find out the exit code for the application by consulting the system event log. NSSM will log the exit code when the application exits. Based on the data found in the registry, NSSM will take one of three actions: If the value data is "Restart" NSSM will try to restart the application as described above. This is its default behaviour. If the value data is "Ignore" NSSM will not try to restart the application but will continue running itself. This emulates the (usually undesirable) behaviour of srvany. The Windows Services console would show the service as still running even though the application has exited. If the value data is "Exit" NSSM will exit gracefully. The Windows Services console would show the service as stopped. If you wish to provide finer-grained control over service recovery you should use this code and edit the failure action manually. Please note that Windows versions prior to Vista will not consider such an exit to be a failure. On older versions of Windows you should use "Suicide" instead. If the value data is "Suicide" NSSM will simulate a crash and exit without informing the service manager. This option should only be used for pre-Vista systems where you wish to apply a service recovery action. Note that if the monitored application exits with code 0, NSSM will only honour a request to suicide if you explicitly configure a registry key for exit code 0. If only the default action is set to Suicide NSSM will instead exit gracefully. Removing services using the GUI ------------------------------- NSSM can also remove services. Run nssm remove to remove a service. You will prompted for confirmation before the service is removed. Try not to remove essential system services... Removing service using the command line --------------------------------------- To remove a service without confirmation from the GUI, run nssm remove confirm Try not to remove essential system services... Logging ------- NSSM logs to the Windows event log. It registers itself as an event log source and uses unique event IDs for each type of message it logs. New versions may add event types but existing event IDs will never be changed. Because of the way NSSM registers itself you should be aware that you may not be able to replace the NSSM binary if you have the event viewer open and that running multiple instances of NSSM from different locations may be confusing if they are not all the same version. Example usage ------------- To install an Unreal Tournament server: nssm install UT2004 c:\games\ut2004\system\ucc.exe server To remove the server: nssm remove UT2004 confirm Building NSSM from source ------------------------- NSSM is known to compile with Visual Studio 6, Visual Studio 2005 and Visual Studio 2008. Credits ------- Thanks to Bernard Loh for finding a bug with service recovery. Thanks to Benjamin Mayrargue (www.softlion.com) for adding 64-bit support. Thanks to Joel Reingold for spotting a command line truncation bug. Thanks to Arve Knudsen for spotting that child processes of the monitored application could be left running on service shutdown, and that a missing registry value for AppDirectory confused NSSM. Thanks to Peter Wagemans and Laszlo Keresztfalvi for suggesting throttling restarts. Thanks to Eugene Lifshitz for finding an edge case in CreateProcess() and for advising how to build messages.mc correctly in paths containing spaces. Licence ------- NSSM is public domain. You may unconditionally use it and/or its source code for any purpose you wish.