Merge pull request #4676 from crosbymichael/no-sig-kill

Send sigterm to child instead of sigkill

pkg/libcontainer/nsinit/init.go

@@ -48,7 +48,9 @@ func (ns *linuxNs) Init(container *libcontainer.Container, uncleanRootfs, consol
 			return fmt.Errorf("setctty %s", err)
 		}
 	}
-	if err := system.ParentDeathSignal(); err != nil {
+	// this is our best effort to let the process know that the parent has died and that it
+	// should it should act on it how it sees fit
+	if err := system.ParentDeathSignal(uintptr(syscall.SIGTERM)); err != nil {
 		return fmt.Errorf("parent death signal %s", err)
 	}
 	if err := setupNewMountNamespace(rootfs, container.Mounts, console, container.ReadonlyFs, container.NoPivotRoot); err != nil {

pkg/system/calls_linux.go

@@ -115,8 +115,8 @@ func Mknod(path string, mode uint32, dev int) error {
 	return syscall.Mknod(path, mode, dev)
 }
 
-func ParentDeathSignal() error {
-	if _, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, syscall.PR_SET_PDEATHSIG, uintptr(syscall.SIGKILL), 0); err != 0 {
+func ParentDeathSignal(sig uintptr) error {
+	if _, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, syscall.PR_SET_PDEATHSIG, sig, 0); err != 0 {
 		return err
 	}
 	return nil