Skip Navigation

Redirecting a command to a running process?

Note: Still trying to navigate communities here on Lemmy to replace those from Reddit. If there is a better place such a question, I would welcome the suggestion.

I'm running a Synology NAS, which uses some flavor of Linux distribution. From there, among everything else running, I have a docker container hosting a Minecraft Bedrock Server. The MCBE server is great for fun, but not so great for resource usage. To handle this, most folks setup something to schedule the server to restart.

Within Synology, there is a task scheduler where I can run a user-defined script to restart the whole container: docker restart mcbe-world

This works, but it's a dirty reboot though. I worried about corrupting the world (which I do regularly backup). From within the Minecraft server terminal, the /stop command will gracefully shut it down.

I can't update the container with another application, like screen, because each MCBE update means replacing the entire container (and so destroying the changes). I am looking to somehow redirect a command to the server if possible.

Using docker exec -it mcbe-world , I can execute what I want within the container.

The person here said, one can "inject commands by running the command as the appropriate account and redirecting it into the server" and they gave the example sudo su -s /bin/bash -c "echo say foobar > /run/service@name" Unfortunately, this isn't so clear and straight forward to me.

Would anyone here be able to articulate this more clearly for me or have an idea as to how I might issue that /stop command from the Synology scheduled script BEFORE restarting the container?

Thanks!

UPDATE: Solution here: https://beehaw.org/comment/1088961

You're viewing a single thread.

15 comments
  • Are you able to docker attach to the container?

    • This looked so promising.

      Via SSH, I can indeed use docker attach and from within I can issue a stop for MC server. Works fine.

      However, the Synology task scheduler via DSM doesn't seem to be able to similarly attach and then issue the stop command. I get this back via email (for when a scheduled task fails):

      Task Scheduler has completed a scheduled task.

      Task: MC Graceful Restart Start time: Tue, 29 Aug 2023 17:19:41 -0500 Stop time: Tue, 29 Aug 2023 17:19:42 -0500 Current status: 127 (Interrupted) Standard output/error:

      the input device is not a TTY /bin/bash: line 1: stop: command not found

15 comments