Spark History Server on S3A FileSystem: ClassNotFoundException

问题

Spark can use Hadoop S3A file system org.apache.hadoop.fs.s3a.S3AFileSystem. By adding the following into the conf/spark-defaults.conf, I can get spark-shell to log to the S3 bucket:

spark.jars.packages               net.java.dev.jets3t:jets3t:0.9.0,com.google.guava:guava:16.0.1,com.amazonaws:aws-java-sdk:1.7.4,org.apache.hadoop:hadoop-aws:2.7.3
spark.hadoop.fs.s3a.impl          org.apache.hadoop.fs.s3a.S3AFileSystem
spark.eventLog.enabled            true
spark.eventLog.dir                s3a://spark-logs-test/
spark.history.fs.logDirectory     s3a://spark-logs-test/
spark.history.provider            org.apache.hadoop.fs.s3a.S3AFileSystem

Spark History Server also loads configuration from conf/spark-defaults.conf, but it seems not to load spark.jars.packages configuration, and throws ClassNotFoundException:

Exception in thread "main" java.lang.ClassNotFoundException: org.apache.hadoop.fs.s3a.S3AFileSystem
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.apache.spark.util.Utils$.classForName(Utils.scala:225)
    at org.apache.spark.deploy.history.HistoryServer$.main(HistoryServer.scala:256)
    at org.apache.spark.deploy.history.HistoryServer.main(HistoryServer.scala)

The Spark source code for loading configuration is different in SparkSubmitArguments.scala and in HistoryServerArguments.scala, in particular the HistoryServerArguments does not seem to load packages.

Is there a way to add the org.apache.hadoop.fs.s3a.S3AFileSystem dependency to the History Server?

回答1:

Did some more digging and figured it out. Here's what was wrong:

The JARs necessary for S3A can be added to $SPARK_HOME/jars (as described in SPARK-15965)

The line

spark.history.provider     org.apache.hadoop.fs.s3a.S3AFileSystem

in $SPARK_HOME/conf/spark-defaults.conf will cause

Exception in thread "main" java.lang.NoSuchMethodException: org.apache.hadoop.fs.s3a.S3AFileSystem.<init>(org.apache.spark.SparkConf)

exception. That line can be safely removed as suggested in this answer.

To summarize:

I added the following JARs to $SPARK_HOME/jars:

jets3t-0.9.3.jar (may be already present with your pre-built Spark binaries, seems to not matter which 0.9.x version)
guava-14.0.1.jar (may be already present with your pre-built Spark binaries, seems to not matter which 14.0.x version)
aws-java-sdk-1.7.4.jar (must be 1.7.4)
hadoop-aws.jar (version 2.7.3) (probably should match the version of Hadoop in your Spark build)

and added this line to $SPARK_HOME/conf/spark-defaults.conf

spark.history.fs.logDirectory     s3a://spark-logs-test/

You'll need some other configuration to enable logging in the first place, but once the S3 bucket has the logs, this is the only configuration that is needed for the History Server.

回答2:

on EMR emr-5.16.0:

I've added the following to my cluster bootstrap:

sudo cp /usr/share/aws/aws-java-sdk/aws-java-sdk-core-*.jar /usr/lib/spark/jars/
sudo cp /usr/share/aws/aws-java-sdk/aws-java-sdk-s3-*.jar /usr/lib/spark/jars/
sudo cp /usr/lib/hadoop/hadoop-aws.jar /usr/lib/spark/jars/

Then in the config of the cluster:

        {
          'Classification': 'spark-defaults',
          'Properties': {
            'spark.eventLog.dir': 's3a://some/path',
            'spark.history.fs.logDirectory': 's3a://some/path',
            'spark.eventLog.enabled': 'true'
          }
        }

If you're going to test this, first stop the spark history server:

sudo stop spark-history-server

Make the config changes

sudo vim /etc/spark/conf.dist/spark-defaults.conf

Then run the copying of JARs as above

Then restart the spark history server:

sudo /usr/lib/spark/sbin/start-history-server.sh

Thanks for the answers above!

回答3:

I added the following jars into my SPARK_HOME/jars directory and it works great:

hadoop-aws-*.jar (Version must be same as hadoop-common which you have)
aws-java-sdk-s3-*.jar (Choose the one compatible with hadoop-aws jar)
aws-java-sdk-*.jar (Choose same version as above one)
aws-java-sdk-core-*.jar (Choose same version as above one)
aws-java-sdk-dynamodb-*.jar (Choose same version as above, Frankly not sure why this is needed but doesn't work for me without this jar).

Edit :

And my spark_defaults.conf has below 3 parameters set :

spark.eventLog.enabled : true
spark.eventLog.dir : s3a://bucket_name/folder_name
spark.history.fs.logDirectory : s3a://bucket_name/folder_name

来源：https://stackoverflow.com/questions/39906536/spark-history-server-on-s3a-filesystem-classnotfoundexception

标签

scala

apache-spark

amazon-s3