cgroup is the only way to track a process and its children, as far as I know Either you use cgroup (in which case, neither the parent pid nor pidfile nor even

cgroup is the only way to track a process and its children, as far as I know Either you use cgroup (in which case, neither the parent pid nor pidfile nor even the process ID are useful), either you do not (in which case, you leak processes) Stopping a service means, in the end, killing all processes in the associated cgroup.