The bit after the image when running docker run from the command line is the command, which are arguments passed to the container’s entrypoint. So in your case, it would be command: -conf /root/Corefile

https://docs.docker.com/compose/compose-file/compose-file-v3/#command

You don’t (and generally shouldn’t) reboot servers. People got this idea that PCs needed to be rebooted because Windows is trash and becomes more unstable the longer it runs. Server OS’s dont have this problem.