thats right. all the driver methods are synchronized.
On Thu, Aug 22, 2013 at 7:04 AM, Li Jin <[email protected]> wrote: > Vinod, > > Thanks for the explanation. Just to clarify, by thread safe, do you also > mean multiple threads can call driver.sendStatusUpdate (and other > functions)? > > Li > > > On Thu, Aug 22, 2013 at 12:34 AM, Vinod Kone <[email protected]> wrote: > >> (1) Is executor per-host instance or per-task instance? >> >> Typically you run one "mesos slave" process per host. A slave can have >> multiple executors running underneath it. Each executor can have multiple >> tasks underneath it. On the receipt of a task, a slave launches a new >> executor if no executor with TaskInfo.ExecutorInfo.executor_id is currently >> alive. If an executor with that id is alive, the task is just passed to the >> executor. On the other hand, if you are utilizing command executor for your >> task the slave will always launch a new executor per task. >> >> (2) If executor is a per-host instance, I would imagine the executor >>> realize tasks as thread/process in launchTask(). How would the executor >>> track task status then? Since the main thread is doing driver.run(), does >>> it need to have another thread check task status and call >>> driver.sendStatusUpdate()? Is MesosExecutorDriver thread safe? >>> >>> >> As you can see from above, executor is not per-host. Having said that, >> yes, executor could realize running different tasks in different threads or >> child processes. The executor could get the exit status of the task from >> the child process exit status (for example see Command Executor) or using >> shared memory if you are using threads. >> >> And yes your main thread will be blocked on run(), so you need another >> thread to track tasks and status updates. Both the scheduler and executor >> drivers are thread safe. You would only get one callback at a time. >> >> >> >>> Thanks, >>> Li >>> >>> >>> On Wed, Aug 21, 2013 at 2:11 PM, Vinod Kone <[email protected]> wrote: >>> >>>> Hey Li, >>>> >>>> While your point about better documentation is duly noted, here are the >>>> answers to your specific questions. >>>> >>>> >>>>> (1) Under TaskInfo, it says "Either ExecutorInfo or CommandInfo should >>>>> be set", that's the difference? >>>>> >>>> >>>> The difference is as follows: >>>> >>>> If you set 'ExecutorInfo', the mesos slave launches your custom >>>> executor as described in the ExecutorInfo and passes it the task. How the >>>> executor runs the task is up to the Executor. >>>> >>>> Instead, if you set 'CommandInfo' on the TaskInfo, the mesos slave >>>> launches an in-built default executor (called 'Command Executor') and >>>> passes the shell command to it. You could use this executor if all you want >>>> do is run an arbitrary shell commands as your tasks. Note that the command >>>> executor exits as soon as the shell command exits. In other words each new >>>> task launches a new command executor. >>>> >>>> Command Executor is also a decent example of how to write an executor >>>> that runs an arbitrary command. See src/launcher/executor.cpp >>>> >>>> >>>>> (2) How should I pass task information (command, env, etc) to the >>>>> executor? Do I put these in the TaskInfo.ExecutorInfo? Or should I put >>>>> these in TaskInfo.ExecutorInfo.data? >>>>> >>>> >>>> Task specific information should be passed via TaskInfo.CommandInfo. >>>> Executor specific information should be passed via >>>> TaskInfo.ExecutorInfo.CommandInfo. The CommandInfo protobuf has fields for >>>> passing environment and command. >>>> >>>> TaskInfo.ExecutorInfo.data can be used to pass arbitrary blob of data >>>> to the executor. The ExecutorInfo will be passed to the executor through >>>> the registered() callback. >>>> >>>> >>>> (3) Is framwork/mesos-submit outdated? the api it uses is different >>>>> from any other examples >>>>> >>>>> >>>> I believe it is a bit out dated. But there has been some recent effort >>>> to resurrect it. Not sure about the current status. >>>> >>>> >>>> >>>>> Thanks, >>>>> Li >>>>> >>>>> >>>>> >>>>> On Wed, Aug 21, 2013 at 10:37 AM, 许立剑 <[email protected]> wrote: >>>>> >>>>>> See include/mesos/mesos.proto. >>>>>> >>>>>> 许立剑 >>>>>> >>>>>> 爱奇艺技术产品中心云平台 >>>>>> >>>>>> *[image: cid:[email protected]]* >>>>>> >>>>>> ☎ 15652344221 | QQ: 276583295 | 12F-W061 <http://www.iqiyi.com/> >>>>>> >>>>>> >>>>>> >>>>>> 2013/8/21 Li Jin <[email protected]> >>>>>> >>>>>>> Hello, >>>>>>> >>>>>>> I am implementing a basic mesos framework(Java) and >>>>>>> executor(Python). I find it quite difficult to find information about >>>>>>> framework/executor protocol. Here is all the information I found >>>>>>> >>>>>>> Doc: >>>>>>> >>>>>>> >>>>>>> https://github.com/apache/mesos/blob/master/docs/App-Framework-development-guide.textile >>>>>>> >>>>>>> This is nice but it doesn't explain things like how to construct >>>>>>> TaskInfo >>>>>>> >>>>>>> Examples: >>>>>>> >>>>>>> src/examples: >>>>>>> These examples are nice to get started, however, these examples >>>>>>> don't show some of the basic things I would like to know (they don't >>>>>>> pass >>>>>>> a command to the executor, for instance) >>>>>>> >>>>>>> framework/mesos-submit: >>>>>>> Mesos-submit actually passed a command to the executor which is >>>>>>> nice. However the python api seems quite different from the java one >>>>>>> and I >>>>>>> find it hard to understand what it's doing and even how to reimplement >>>>>>> this >>>>>>> in Java >>>>>>> >>>>>>> In general, I couldn't find doc/example about all the protobuf >>>>>>> (TaskInfo, ExecutorInfo, etc) objects and how to use them. >>>>>>> >>>>>>> I am wondering if there are more for me to look at. If not, I guess >>>>>>> my best shot is take a look at the source code or Chronos >>>>>>> >>>>>>> Thanks, >>>>>>> Li >>>>>>> >>>>>> >>>>>> >>>>> >>>> >>> >> >
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