Restarting a Greengrass component with a container creates two instances of that container

You can restart the component and have it restart the container. Essentially Greengrass is sending a SIGTERM to the process running in the 'Run' portion of the lifecycle when stopping. In this case, the docker run command receives the signal. If the container can process the signal and exit gracefully, this will work. Here is more details on the process.

If the container cannot process the SIGTERM, the other way to mange is to use the Startup and Shutdown lifecycles within the recipe file. In this case, you can change your docker run to name the container and run in detached (background) mode. then when Greengrass stops the component, the Shutdown lifecycle would have a docker stop my_container_name which will complete the shutdown.

Using either approach will ensure that only one instance of the container is running. Note that there may be edge cases, so depending upon the situation, you may want to add additional logic to the recipe file to check for errant processes or running containers just like you would if do this directly from a shell script.

Hope this helps!