Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
Hadoop >> mail # dev >> Help with error

Copy link to this message
Re: Help with error
Hi Bobby

On Apr 9, 2012, at 11:40 AM, Robert Evans wrote:

> What do you mean by relocated some supporting files to HDFS?  How do you relocate them?  What API do you use?

I use the LocalResource and FileSystem classes to do the relocation, per the Hadoop example:

// set local resources for the application master
// local files or archives as needed
// In this scenario, the jar file for the application master is part of the local resources
Map<String, LocalResource> localResources = new HashMap<String, LocalResource>();

LOG.info("Copy openmpi tarball from local filesystem and add to local environment");
// Copy the application master jar to the filesystem
// Create a local resource to point to the destination jar path
FileSystem fs;
FileStatus destStatus;
try {
   fs = FileSystem.get(conf);
   Path src = new Path(pathOMPItarball);
   String pathSuffix = appName + "/" + appId.getId();    
   Path dst = new Path(fs.getHomeDirectory(), pathSuffix);
   try {
fs.copyFromLocalFile(false, true, src, dst);
try {
   destStatus = fs.getFileStatus(dst);
   LocalResource amJarRsrc = Records.newRecord(LocalResource.class);

   // Set the type of resource - file or archive
   // archives are untarred at destination
   // Set visibility of the resource
   // Setting to most private option
   // Set the resource to be copied over
   // Set timestamp and length of file so that the framework
   // can do basic sanity checks for the local resource
   // after it has been copied over to ensure it is the same
   // resource the client intended to use with the application
   localResources.put("openmpi",  amJarRsrc);
} catch (Throwable t) {
   LOG.fatal("Error on file status", t);
   } catch (Throwable t) {
LOG.fatal("Error on copy from local file", t);
} catch (Throwable t) {
   LOG.fatal("Error getting filesystem configuration", t);

Note that this appears to work fine when the local resource type was "file" - at least, I was able to make a simple program work that way. Problem I'm having is when I move an archive, which is why I was hoping to look at the HDFS end to see what files are present, and in what locations so I can set the paths accordingly.

> --Bobby Evans
> On 4/9/12 11:10 AM, "Ralph Castain" <[EMAIL PROTECTED]> wrote:
> Hi folks
> I'm trying to develop an AM for the 0.23 branch and running into a problem that I'm having difficulty debugging. My client relocates some supporting files to HDFS, creates the application object for the AM, and submits it to the RM.
> The file relocation request doesn't generate an error, so I must assume it succeeded. It would be nice if there was some obvious way to verify that, but I haven't discovered it. Can anyone give me a hint? I tried asking hdfs to -ls, but all I get is that "." doesn't exist. I have no idea where the file would be placed, if it would persist once the job fails, etc.
> When the job is submitted, all I get is an "Error 500", which tells me nothing. Reminds me of the old days of 40 years ago when you'd get the dreaded "error 11", which meant anything from a divide by zero to a memory violation. Are there any debug flags I could set that might provide more info?
> Thanks
> Ralph