-Re: Distribution of native executables and data for YARN-based execution
The "local resources" you mentioned is the exact solution for this. For each LocalResource, you also mention a LocalResourceVisibility which takes one of the three values today - PUBLIC, PRIVATE and APPLICATON.
PUBLIC resources are downloaded only once and shared by any application running on that node.
PRIVATE resources are downloaded only once and shared by any application run by the same user on that node
APPLICATION resources are downloaded per application and removed after the application finishes.
Seems like you want PUBLIC or PRIVATE.
Note that for PUBLIC resources to work, the corresponding files need to be public on HDFS too.
Also if the remote files on HDFS are updated, these local files will be uploaded afresh again on each node where your containers run.
+Vinod Kumar Vavilapalli
On May 16, 2013, at 2:21 PM, John Lilley wrote:
> I am attempting to distribute the execution of a C-based program onto a Hadoop cluster, without using MapReduce. I read that YARN can be used to schedule non-MapReduce applications by programming to the ASM/RM interfaces. As I understand it, eventually I get down to specifying each sub-task via ContainerLaunchContext.setCommands().
> However, the program and shared libraries need to be stored on each worker’s local disk to run. In addition there is a hefty data set that the application uses (say, 4GB) that is accessed via regular open()/read() calls by a library. I thought a decent strategy would be to push the program+data package to a known folder in HDFS, then launch a “bootstrap” that compared the HDFS folder version to a local folder, copying any updated files as needed before launching the native application task.
> Are there better approaches? I notice that one can implicitly copy “local resources” as part of the launch, but I don’t want to copy 4GB every time, only occasionally when the application or reference data is updated. Also, will my bootstrapper be allowed to set executable-mode bits on the programs after they are copied?