Unfortunately most init systems don't do this correctly within Docker since they're built for hardware shutdowns instead. This causes processes to be hard killed with SIGKILL, which doesn't give them a chance to correctly deinitialize things.

A “warning” signal is sent first, then, after a timeout, a “kill” signal, similar to the way init(8) operates on shutdown.

if the process does not react on a normal kill, you may want to add an additional kill -9 a few seconds afterwards.

We can ask timeout to try to stop the program using SIGTERM, and to only send in SIGKILL if SIGTERM didn’t work. To do this, we use the -k (kill after) option. The -k option requires a time value as a parameter.