code: private boolean scheduleRolloutGroup(final JpaRollout rollout, final JpaRolloutGroup group) {
          final long targetsInGroup = rolloutTargetGroupRepository.countByRolloutGroup(group);
          final long countOfActions = actionRepository.countByRolloutAndRolloutGroup(rollout, group);
  
          long actionsLeft = targetsInGroup - countOfActions;
          if (actionsLeft > 0) {
              actionsLeft -= createActionsForRolloutGroup(rollout, group);
          }
  
          if (actionsLeft <= 0) {
              group.setStatus(RolloutGroupStatus.SCHEDULED);
              rolloutGroupRepository.save(group);
              return true;
          }
          return false;
      }
docs: Schedules a group of the rollout. Scheduled Actions are created to
  achieve this. The creation of those Actions is allowed to fail.