Re: Issues with Flink Batch and Hadoop dependency

Posted by Arvid Heise-3 on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Issues-with-Flink-Batch-and-Hadoop-dependency-tp37795p37836.html

Hi Dan,

Your approach in general is good. You might want to use the bundled hadoop uber jar [1] to save some time if you find the appropriate version. You can also build your own version and include it then in lib/.

In general, I'd recommend moving away from sequence files. As soon as you change your records minimally, everything falls apart. Going with established binary formats like Avro or Parquet is usually desired also because of the additional tooling and pays quickly off in the long run.

[1] https://flink.apache.org/downloads.html#additional-components

On Sat, Aug 29, 2020 at 10:50 PM Dan Hill <[hidden email]> wrote:

I was able to get a basic version to work by including a bunch of hadoop and s3 dependencies in the job jar and hacking in some hadoop config values.  It's probably not optimal but it looks like I'm unblocked.

On Fri, Aug 28, 2020 at 12:11 PM Dan Hill <[hidden email]> wrote:

I'm assuming I have a simple, common setup problem.  I've spent 6 hours debugging and haven't been able to figure it out.  Any help would be greatly appreciated.

Problem

I have a Flink Streaming job setup that writes SequenceFiles in S3.  When I try to create a Flink Batch job to read these Sequence files, I get the following error:

NoClassDefFoundError: org/apache/hadoop/mapred/FileInputFormat

It fails on this readSequenceFile.

env.createInput(HadoopInputs.readSequenceFile(Text.class, ByteWritable.class, INPUT_FILE))

If I directly depend on org-apache-hadoop/hadoop-mapred when building the job, I get the following error when trying to run the job:

Caused by: org.apache.hadoop.fs.UnsupportedFileSystemException: No FileSystem for scheme "s3"
    at org.apache.hadoop.fs.FileSystem.getFileSystemClass(FileSystem.java:3332)
    at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:3352)

    at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:124)
    at org.apache.hadoop.fs.FileSystem$Cache.getInternal(FileSystem.java:3403)
    at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:3371)
    at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:477)

    at org.apache.hadoop.fs.Path.getFileSystem(Path.java:361)
    at org.apache.hadoop.mapred.FileInputFormat.listStatus(FileInputFormat.java:209)

    at org.apache.hadoop.mapred.SequenceFileInputFormat.listStatus(SequenceFileInputFormat.java:48)
    at org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:254)
    at org.apache.flink.api.java.hadoop.mapred.HadoopInputFormatBase.createInputSplits(HadoopInputFormatBase.java:150)
    at org.apache.flink.api.java.hadoop.mapred.HadoopInputFormatBase.createInputSplits(HadoopInputFormatBase.java:58)
    at org.apache.flink.runtime.executiongraph.ExecutionJobVertex.<init>(ExecutionJobVertex.java:257)

Extra context

I'm using this Helm chart for creating Flink.  I'm using v1.10.1.

Questions

Are there any existing projects that read batch Hadoop file formats from S3?

I've looked at these instructions for Hadoop Integration.  I'm assuming my configuration is wrong.  I'm also assuming I need the hadoop dependency properly setup in the jobmanager and taskmanager (not in the job itself).  If I use this Helm chart, do I need to download a hadoop common jar into the Flink images for jobmanager and taskmanager?  Are there pre-built images which I can use that already have the dependencies setup?

- Dan

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