// assumes that: caller has acquired scheduler lock and that the task is still pending
//
// bind does not actually do the binding itself, but launches the pod as a Mesos task. The
// kubernetes executor on the slave will finally do the binding. This is different from the
// upstream scheduler in the sense that the upstream scheduler does the binding and the
// kubelet will notice that and launches the pod.
func (b *binder) bind(ctx api.Context, binding *api.Binding, task *podtask.T) (err error) {
// sanity check: ensure that the task hasAcceptedOffer(), it's possible that between
// Schedule() and now that the offer for this task was rescinded or invalidated.
// ((we should never see this here))
if !task.HasAcceptedOffer() {
return fmt.Errorf("task has not accepted a valid offer %v", task.ID)
}
// By this time, there is a chance that the slave is disconnected.
offerId := task.GetOfferId()
if offer, ok := b.sched.Offers().Get(offerId); !ok || offer.HasExpired() {
// already rescinded or timed out or otherwise invalidated
return b.rollback(task, fmt.Errorf("failed prior to launchTask due to expired offer for task %v", task.ID))
}
if err = b.prepareTaskForLaunch(ctx, binding.Target.Name, task, offerId); err == nil {
log.V(2).Infof(
"launching task: %q on target %q slave %q for pod \"%v/%v\", resources %v",
task.ID, binding.Target.Name, task.Spec.SlaveID, task.Pod.Namespace, task.Pod.Name, task.Spec.Resources,
)
if err = b.sched.LaunchTask(task); err == nil {
b.sched.Offers().Invalidate(offerId)
task.Set(podtask.Launched)
if err = b.sched.Tasks().Update(task); err != nil {
// this should only happen if the task has been removed or has changed status,
// which SHOULD NOT HAPPEN as long as we're synchronizing correctly
log.Errorf("failed to update task w/ Launched status: %v", err)
}
return
}
}
return b.rollback(task, fmt.Errorf("Failed to launch task %v: %v", task.ID, err))
}
