{"id":10132,"date":"2021-07-05T13:02:38","date_gmt":"2021-07-05T20:02:38","guid":{"rendered":"https:\/\/www.coretechnologies.com\/blog\/?p=10132"},"modified":"2022-04-19T21:43:30","modified_gmt":"2022-04-20T04:43:30","slug":"net-vs-sc","status":"publish","type":"post","link":"https:\/\/www.coretechnologies.com\/blog\/windows-services\/net-vs-sc\/","title":{"rendered":"Q&A: Should I use NET or SC to start\/stop\/restart our Windows Services?"},"content":{"rendered":"
\"Q&A:<\/div>\n
\n  My team manages a few third-party Windows Services. We plan to write scripts that start, stop and restart the services as part of regular maintenance through batch files. Should we use NET<\/a> or SC<\/a>? What’s the difference? Is one more reliable?<\/p>\n

— Silvia<\/p>\n<\/div>\n

Hi Silvia.<\/p>\n

Yes, both commands are adept at manipulating the state of a Windows Service. For example, both NET STOP<\/b> and SC STOP<\/b> will cause a service to shut down.<\/p>\n

And both NET and SC are mature, stable and reliable utilities. Apparently Microsoft has worked out all the bugs over the past 30 years. \ud83d\ude42<\/p>\n

However, as far as developing batch files to start, stop and restart services, there is one subtle but important difference between the two utilities.<\/p>\n

NET makes a request and waits to confirm…<\/h2>\n

When you issue a NET START or NET STOP command, NET.EXE:<\/p>\n

    \n
  1. \n

    \nOpens the Windows Service Control Manager (with OpenSCManager<\/a>).\n<\/p>\n<\/li>\n

  2. \n

    \nOpens the service (with OpenService<\/a>).\n<\/p>\n<\/li>\n

  3. \n

    \nRejects the operation if the service is not in a compatible state. For example, if a stop was requested but the service is already stopped, an error is returned (likely exit code 2).\n<\/p>\n<\/li>\n

  4. \n

    \nRequests that the service transitions to the appropriate state (with ControlService<\/a>).\n<\/p>\n<\/li>\n

  5. \n

    For the next 30 seconds:<\/p>\n

      \n
    1. \n

      Periodically checks the state of the service (with QueryServiceStatusEx<\/a>).<\/p>\n<\/li>\n

    2. \n

      Returns success (exit code 0) if the service transitions to the expected end state.<\/p>\n<\/li>\n

    3. \n

      Keeps waiting if the service has not transitioned to the expected end state.<\/p>\n<\/li>\n<\/ol>\n

    4. \n

      \nReturns an error if 30 seconds has elapsed but the service has not transitioned to expected end state.\n<\/p>\n<\/li>\n<\/ol>\n

      … But SC simply makes a request and exits<\/h2>\n

      On the other hand, when you run SC START or SC STOP command, SC.EXE:<\/p>\n

        \n
      1. \n

        \nOpens the Windows Service Control Manager (with OpenSCManager<\/a>).\n<\/p>\n<\/li>\n

      2. \n

        \nOpens the service (with OpenService<\/a>).\n<\/p>\n<\/li>\n

      3. \n

        \nRejects the operation if the service is not in a compatible state. For example, if a stop was requested but the service is already stopped, an error is returned (likely exit code 2).\n<\/p>\n<\/li>\n

      4. \n

        \nRequests that the service transitions to the appropriate state (with ControlService<\/a>).\n<\/p>\n<\/li>\n

      5. \n

        \nReturns success (exit code 0).\n<\/p>\n<\/li>\n<\/ol>\n

        SC does not wait for the service to stop or start.<\/p>\n

        What the difference means for your batch files<\/h2>\n

        Because SC does not wait for the service to transition to the desired state, you have to be careful when you use SC in batch files.<\/p>\n

        For example, to restart a service, this sequence looks like it should do the trick:<\/p>\n

        \nSC STOP ServiceName
        \nSC START ServiceName\n<\/div>\n

        And it works, for many services!<\/p>\n

        Indeed, here is the Print Spooler service quickly transitioning through the PENDING states and ending up running, as desired:<\/p>\n

        \"Restarting<\/a><\/div>\n

        However, things go awry if the service takes a few seconds to stop.<\/p>\n

        For example, our CloudFileServer service takes 2-5 seconds to terminate (while it closes and uploads transient files to a remote site). The SC script doesn’t fare as well with that service:<\/p>\n

        \"Restarting<\/a><\/div>\n

        As you can see, SC STOP succeeds and the service promptly transitions to the STOP_PENDING state. Unfortunately, the subsequent SC START fails with the “already running” error because the service is still shutting down — it has not yet stopped. And the final result (not pictured) is a dead service — the opposite of what we were hoping to achieve!<\/p>\n

        On the contrary, the equivalent sequence with the NET command worked much better:<\/p>\n

        \"Restarting<\/a><\/div>\n

        However, NET will run into the same problem as SC if the service takes longer than 30 seconds to stop.<\/p>\n

        You should pause or confirm when using SC<\/h2>\n

        Of course, you can have SC behave like NET by adding extra code to your script. For instance, adding the TIMEOUT command<\/a> (which pauses for a fixed period) will give a slow service the chance to stop gracefully before attempting to restart it:<\/p>\n

        \nSC STOP CloudFileServer
        \nTIMEOUT \/T 10
        \nSC START CloudFileServer\n<\/div>\n

        This updated script works well with our CloudFileServer service:<\/p>\n

        \"Restarting<\/a><\/div>\n

        Similarly, you can add code to check the state of the service<\/a> (with the SC QUERY command) and react accordingly. That approach is more complicated, but it may be worth it in your situation.<\/p>\n

        Consider ServicePilot when working with slow or busy services<\/h2>\n

        If you are working with services that take a while to start or stop, you should consider using our free ServicePilot<\/a> command line utility.<\/p>\n

        Like NET.EXE, ServicePilot will wait to confirm the desired end state. However, ServicePilot allows you to specify the time to wait for the transition to complete.<\/p>\n

        Here is ServicePilot controlling SlowStopService — our internally developed service which can take up to a minute to stop:<\/p>\n

        \"Restarting<\/a><\/div>\n

        \nBest of luck with your batch files!<\/p>\n