Interface Scheduler

src/java/src/org/apache/mesos/Scheduler.java:40–213

Callback interface to be implemented by frameworks' schedulers. Note that only one callback will be invoked at a time, so it is not recommended that you block within a callback because it may cause a deadlock. Each callback includes a reference to the scheduler driver that was used to run this s

 * itself.
 */
public interface Scheduler {
  /**
   * Invoked when the scheduler successfully registers with a Mesos
   * master. A unique ID (generated by the master) used for
   * distinguishing this framework from others and MasterInfo
   * with the IP and port of the current master are provided as arguments.
   *
   * @param driver      The scheduler driver that was registered.
   * @param frameworkId The framework ID generated by the master.
   * @param masterInfo  Info about the current master, including IP and port.
   *
   * @see SchedulerDriver
   * @see FrameworkID
   * @see MasterInfo
   */
  void registered(SchedulerDriver driver,
                  FrameworkID frameworkId,
                  MasterInfo masterInfo);

  /**
   * Invoked when the scheduler reregisters with a newly elected Mesos master.
   * This is only called when the scheduler has previously been registered.
   * MasterInfo containing the updated information about the elected master
   * is provided as an argument.
   *
   * @param driver      The driver that was reregistered.
   * @param masterInfo  The updated information about the elected master.
   *
   * @see SchedulerDriver
   * @see MasterInfo
   */
  void reregistered(SchedulerDriver driver, MasterInfo masterInfo);

  /**
   * Invoked when resources have been offered to this framework. A
   * single offer will only contain resources from a single slave.
   * Resources associated with an offer will not be re-offered to
   * _this_ framework until either (a) this framework has rejected
   * those resources (see {@link SchedulerDriver#launchTasks}) or (b)
   * those resources have been rescinded (see {@link Scheduler#offerRescinded}).
   * Note that resources may be concurrently offered to more than one
   * framework at a time (depending on the allocator being used). In
   * that case, the first framework to launch tasks using those
   * resources will be able to use them while the other frameworks
   * will have those resources rescinded (or if a framework has
   * already launched tasks with those resources then those tasks will
   * fail with a TASK_LOST status and a message saying as much).
   *
   * @param driver  The driver that was used to run this scheduler.
   * @param offers  The resources offered to this framework.
   *
   * @see SchedulerDriver
   * @see Offer
   */
  void resourceOffers(SchedulerDriver driver, List<Offer> offers);

  /**
   * Invoked when an offer is no longer valid (e.g., the slave was