Daniel Lezcano [daniel.lezcano@xxxxxxx] wrote: > Ferenc Wagner wrote: > >> I noticed something strange: >> >> # lxc-start -n jail -s lxc.mount.entry="/ /tmp/jail none bind 0 0" -s lxc.rootfs=/tmp/jail -s lxc.pivotdir=/mnt /bin/sleep 1000 >> (in another terminal) >> # lxc-ps --lxc >> CONTAINER PID TTY TIME CMD >> jail 4173 pts/1 00:00:00 sleep >> # kill 4173 >> (this does not kill the sleep!) >> # strace -p 4173 >> Process 4173 attached - interrupt to quit >> restart_syscall(<... resuming interrupted call ...> = ? ERESTART_RESTARTBLOCK (To be restarted) >> --- SIGTERM (Terminated) @ 0 (0) --- >> Process 4173 detached >> # lxc-ps --lxc >> CONTAINER PID TTY TIME CMD >> jail 4173 pts/1 00:00:00 sleep >> # fgrep -i sig /proc/4173/status SigQ: 1/16382 >> SigPnd: 0000000000000000 >> SigBlk: 0000000000000000 >> SigIgn: 0000000000000000 >> SigCgt: 0000000000000000 >> # kill -9 4173 >> >> That is, the jailed sleep process could be killed by SIGKILL only, even >> though (according to strace) SIGTERM was delivered and it isn't handled >> specially. Why does this happen? Yes, SIGKILL is the only reliable way to terminate a container-init. container-init needs to be immune to signals from within the container but be open to receiving signals from parent container. These requirements complicate the implementation of allowing SIGINIT/SIGTERM etc to container-init from parent container. Besides a realistic container-init would block such signals, in which case the complexity in the kernel could be viewed as unnecessary. Hope that helps, Sukadev _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
