[Mesos]框架开发手册（Framework Development Guide）

[Mesos]框架开发手册（Framework Development Guide）

原文：http://mesos.apache.org/documentation/latest/app-framework-development-guide/

－－－文档指导我们在mesos管理框架内添加应用

从MESOS_HOME/src/examples/目录中去获取你选择语言的例子，它可以给你如何实现mesos框架调度和执行器一些提示。

创建自己的框架调度器（Create your Framework Scheduler）

你能用C, C++, Java/Scala, or Python来实现一个调度器，你的调度器需要继承Scheduler这个类（请查看下面的API）。调度器需要创建SchedulerDriver类（用于调度器和mesos master之间的交流）并且调度器后面调用SchedulerDriver.run()。

Scheduler API

声明定义在 MESOS_HOME/include/mesos/scheduler.hpp文件内

 /**
   * Empty virtual destructor (necessary to instantiate subclasses).
   */
  virtual ~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.
   */
  virtual void registered(SchedulerDriver* driver,
                          const FrameworkID& frameworkId,
                          const MasterInfo& masterInfo) = 0;

  /**
   * Invoked when the scheduler re-registers 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.
   */
  virtual void reregistered(SchedulerDriver* driver,
                            const MasterInfo& masterInfo) = 0;

  /**
   * Invoked when the scheduler becomes "disconnected" from the master
   * (e.g., the master fails and another is taking over).
   */
  virtual void disconnected(SchedulerDriver* driver) = 0;

  /**
   * 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 SchedulerDriver::launchTasks) or (b) those
   * resources have been rescinded (see Scheduler::offerRescinded).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   * will have those resources rescinded (or if a framework has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).
   */
  virtual void resourceOffers(SchedulerDriver* driver,
                              const std::vector& offers) = 0;

  /**
   * Invoked when an offer is no longer valid (e.g., the slave was
   * lost or another framework used resources in the offer). If for
   * whatever reason an offer is never rescinded (e.g., dropped
   * message, failing over framework, etc.), a framwork that attempts
   * to launch tasks using an invalid offer will receive TASK_LOST
   * status updats for those tasks (see Scheduler::resourceOffers).
   */
  virtual void offerRescinded(SchedulerDriver* driver,
                              const OfferID& offerId) = 0;

  /**
   * Invoked when the status of a task has changed (e.g., a slave is
   * lost and so the task is lost, a task finishes and an executor
   * sends a status update saying so, etc). Note that returning from
   * this callback _acknowledges_ receipt of this status update! If
   * for whatever reason the scheduler aborts during this callback (or
   * the process exits) another status update will be delivered (note,
   * however, that this is currently not true if the slave sending the
   * status update is lost/fails during that time).
   */
  virtual void statusUpdate(SchedulerDriver* driver,
                            const TaskStatus& status) = 0;

  /**
   * Invoked when an executor sends a message. These messages are best
   * effort; do not expect a framework message to be retransmitted in
   * any reliable fashion.
   */
  virtual void frameworkMessage(SchedulerDriver* driver,
                                const ExecutorID& executorId,
                                const SlaveID& slaveId,
                                const std::string& data) = 0;

  /**
   * Invoked when a slave has been determined unreachable (e.g.,
   * machine failure, network partition). Most frameworks will need to
   * reschedule any tasks launched on this slave on a new slave.
   */
  virtual void slaveLost(SchedulerDriver* driver,
                         const SlaveID& slaveId) = 0;

  /**
   * Invoked when an executor has exited/terminated. Note that any
   * tasks running will have TASK_LOST status updates automagically
   * generated.
   */
  virtual void executorLost(SchedulerDriver* driver,
                            const ExecutorID& executorId,
                            const SlaveID& slaveId,
                            int status) = 0;

  /**
   * Invoked when there is an unrecoverable error in the scheduler or
   * scheduler driver. The driver will be aborted BEFORE invoking this
   * callback.
   */
  virtual void error(SchedulerDriver* driver, const std::string& message) = 0;

构建自己的执行器(Create your Framework Executor)

框架执行器需要继承Executor这个类，它需要重写launchTask()这个方法。你能定义执行器里面$MESOS_HOME这个环境变量去控制Mesos在哪里执行。

Executor API

声明定义在 MESOS_HOME/include/mesos/executor.hpp

 /**
   * Invoked once the executor driver has been able to successfully
   * connect with Mesos. In particular, a scheduler can pass some
   * data to it's executors through the FrameworkInfo.ExecutorInfo's
   * data field.
   */
  virtual void registered(ExecutorDriver* driver,
                          const ExecutorInfo& executorInfo,
                          const FrameworkInfo& frameworkInfo,
                          const SlaveInfo& slaveInfo) = 0;

  /**
   * Invoked when the executor re-registers with a restarted slave.
   */
  virtual void reregistered(ExecutorDriver* driver,
                            const SlaveInfo& slaveInfo) = 0;

  /**
   * Invoked when the executor becomes "disconnected" from the slave
   * (e.g., the slave is being restarted due to an upgrade).
   */
  virtual void disconnected(ExecutorDriver* driver) = 0;

  /**
   * Invoked when a task has been launched on this executor (initiated
   * via Scheduler::launchTasks). Note that this task can be realized
   * with a thread, a process, or some simple computation, however, no
   * other callbacks will be invoked on this executor until this
   * callback has returned.
   */
  virtual void launchTask(ExecutorDriver* driver,
                          const TaskInfo& task) = 0;

  /**
   * Invoked when a task running within this executor has been killed
   * (via SchedulerDriver::killTask). Note that no status update will
   * be sent on behalf of the executor, the executor is responsible
   * for creating a new TaskStatus (i.e., with TASK_KILLED) and
   * invoking ExecutorDriver::sendStatusUpdate.
   */
  virtual void killTask(ExecutorDriver* driver, const TaskID& taskId) = 0;

  /**
   * Invoked when a framework message has arrived for this
   * executor. These messages are best effort; do not expect a
   * framework message to be retransmitted in any reliable fashion.
   */
    virtual void frameworkMessage(ExecutorDriver* driver,
                                  const std::string& data) = 0;

  /**
   * Invoked when the executor should terminate all of it's currently
   * running tasks. Note that after a Mesos has determined that an
   * executor has terminated any tasks that the executor did not send
   * terminal status updates for (e.g., TASK_KILLED, TASK_FINISHED,
   * TASK_FAILED, etc) a TASK_LOST status update will be created.
   */
  virtual void shutdown(ExecutorDriver* driver) = 0;

  /**
   * Invoked when a fatal error has occurred with the executor and/or
   * executor driver. The driver will be aborted BEFORE invoking this
   * callback.
   */
  virtual void error(ExecutorDriver* driver, const std::string& message) = 0;

安装框架(Install your Framework)

你需要把你的框架放到所有从机器都能获取到地方，如何你要运行HDFS,那执行器就需要放到HDFS上。然后你告诉mesos如何获取 MesosSchedulerDriver的构建参数 ExecutorInfo（src/examples/java/TestFramework.java就是这样的一个例子）。ExecutorInfo是一个Protocol Buffer Message类（在 include/mesos/mesos.proto里面定义），我们也可以设置这样的HDFS://path/to/executor/这样的uri。如果你有特殊的执行器储存地方，也可以更改 frameworks_home配置项（默认是 MESOS_HOME/frameworks）为 你的mesos-slave进程，然后设置 ExecutorInfo在一个相关的路径下，而去从机器也会通过提高的相关路径预测frameworks_home的值。

一旦你的确定执行器可以在mesos-slaves运行，那你可以运用在mesos master注册的调度器，然后接受资源请求。