-// TrackContainer starts a tracker for given uuid if one is not already existing, despite its state.
-func (d *Dispatcher) TrackContainer(uuid string) {
- d.mtx.Lock()
- defer d.mtx.Unlock()
-
- if d.trackers == nil {
- d.trackers = make(map[string]*runTracker)
- }
-
- _, alreadyTracking := d.trackers[uuid]
- if alreadyTracking {
- return
- }
-
+// TrackContainer ensures a tracker is running for the given UUID,
+// regardless of the current state of the container (except: if the
+// container is locked by a different dispatcher, a tracker will not
+// be started). If the container is not in Locked or Running state,
+// the new tracker will close down immediately.
+//
+// This allows the dispatcher to put its own RunContainer func into a
+// cleanup phase (for example, to kill local processes created by a
+// prevous dispatch process that are still running even though the
+// container state is final) without the risk of having multiple
+// goroutines monitoring the same UUID.
+func (d *Dispatcher) TrackContainer(uuid string) error {