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Steve Loughran commented on SPARK-22657: ---------------------------------------- if you look at HADOOP-14138 you can see why we cut s3a from the list; HADOOP-14132 how we culled the references. Not only brittle, too much overhead in classloading, especially in shading. I think we could switch to something more minimal, but even there hadn't planned to reset the enum on classloader changes. Happy to add a static method to trigger that though. Indeed, if you submit the patch for HADOOP-14132, with tests, you can make sure it suits your needs > Hadoop fs implementation classes are not loaded if they are part of the app > jar or other jar when --packages flag is used > -------------------------------------------------------------------------------------------------------------------------- > > Key: SPARK-22657 > URL: https://issues.apache.org/jira/browse/SPARK-22657 > Project: Spark > Issue Type: Bug > Components: Spark Core > Affects Versions: 2.3.0 > Reporter: Stavros Kontopoulos > > To reproduce this issue run: > ./bin/spark-submit --master mesos://leader.mesos:5050 \ > --packages com.github.scopt:scopt_2.11:3.5.0 \ > --conf spark.cores.max=8 \ > --conf > spark.mesos.executor.docker.image=mesosphere/spark:beta-2.1.1-2.2.0-2-hadoop-2.6 > \ > --conf spark.mesos.executor.docker.forcePullImage=true \ > --class S3Job > http://s3-us-west-2.amazonaws.com/arand-sandbox-mesosphere/dcos-spark-scala-tests-assembly-0.1-SNAPSHOT.jar > \ > --readUrl s3n://arand-sandbox-mesosphere/big.txt --writeUrl > s3n://arand-sandbox-mesosphere/linecount.out > within a container created with > mesosphere/spark:beta-2.1.1-2.2.0-2-hadoop-2.6 image > You will get: "Exception in thread "main" java.io.IOException: No FileSystem > for scheme: s3n" > This can be run reproduced with local[*] as well, no need to use mesos, this > is not mesos bug. > The specific spark job used above can be found here: > https://github.com/mesosphere/spark-build/blob/d5c50e9ae3b1438e0c4ba96ff9f36d5dafb6a466/tests/jobs/scala/src/main/scala/S3Job.scala > > Can be built with sbt assembly in that dir. > Using this code : > https://gist.github.com/skonto/4f5ff1e5ede864f90b323cc20bf1e1cbat the > beginning of the main method... > you get the following output : > https://gist.github.com/skonto/d22b8431586b6663ddd720e179030da4 > (Use > http://s3-eu-west-1.amazonaws.com/fdp-stavros-test/dcos-spark-scala-tests-assembly-0.1-SNAPSHOT.jar > to to get the modified job) > The job works fine if --packages is not used. > The commit that introduced this issue is (before that things work as > expected): > 5800144a54f5c0180ccf67392f32c3e8a51119b1[m -[33m[m [SPARK-21012][SUBMIT] Add > glob support for resources adding to Spark [32m(5 months ago) > [1;34m<jerryshao>[m Thu, 6 Jul 2017 15:32:49 +0800 > The exception comes from here: > https://github.com/apache/hadoop/blob/trunk/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java#L3311 > https://github.com/apache/spark/pull/18235/files, check line 950, this is > where a filesystem is first created. > The Filesystem class is initialized there, before the main of the spark job > is launched... the reason is --packages logic uses hadoop libraries to > download files.... > Maven resolution happens before the app jar and the resolved jars are added > to the classpath. So at that moment there is no s3n to add to the static map > when the Filesystem static members are first initialized and also filled due > to the first FileSystem instance created (SERVICE_FILE_SYSTEMS). > Later in the spark job main where we try to access the s3n filesystem (create > a second filesystem) we get the exception (at this point the app jar has the > s3n implementation in it and its on the class path but that scheme is not > loaded in the static map of the Filesystem class)... > hadoopConf.set("fs.s3n.impl.disable.cache", "true") has no effect since the > problem is with the static map which is filled once and only once. > That's why we see two prints of the map contents in the output(gist) above > when --packages is used. The first print is before creating the s3n > filesystem. We use reflection there to get the static map's entries. When > --packages is not used that map is empty before creating the s3n filesystem > since up to that point the Filesystem class is not yet loaded by the > classloader. -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org