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https://issues.apache.org/jira/browse/SPARK-20328?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15968423#comment-15968423
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Marcelo Vanzin commented on SPARK-20328:
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bq. But it shouldn't need delegation tokens at all, right?
It depends. e.g. on YARN, when you submit in cluster mode, the driver is
running in the cluster and all it has are delegation tokens. (The TGT is only
available to the launcher process.)
Actually it would be interesting to understand how that case works internally;
because if that code is trying to generate delegation tokens, it should
theoretically fail in the above scenario. So maybe it doesn't generate tokens
if they're already there, and that could be a workaround for your case too.
> HadoopRDDs create a MapReduce JobConf, but are not MapReduce jobs
> -----------------------------------------------------------------
>
> Key: SPARK-20328
> URL: https://issues.apache.org/jira/browse/SPARK-20328
> Project: Spark
> Issue Type: Bug
> Components: Spark Core
> Affects Versions: 2.1.0, 2.1.1, 2.1.2
> Reporter: Michael Gummelt
>
> In order to obtain {{InputSplit}} information, {{HadoopRDD}} creates a
> MapReduce {{JobConf}} out of the Hadoop {{Configuration}}:
> https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala#L138
> Semantically, this is a problem because a HadoopRDD does not represent a
> Hadoop MapReduce job. Practically, this is a problem because this line:
> https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala#L194
> results in this MapReduce-specific security code being called:
> https://github.com/apache/hadoop/blob/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/security/TokenCache.java#L130,
> which assumes the MapReduce master is configured (e.g. via
> {{yarn.resourcemanager.*}}). If it isn't, an exception is thrown.
> So I'm seeing this exception thrown as I'm trying to add Kerberos support for
> the Spark Mesos scheduler:
> {code}
> Exception in thread "main" java.io.IOException: Can't get Master Kerberos
> principal for use as renewer
> at
> org.apache.hadoop.mapreduce.security.TokenCache.obtainTokensForNamenodesInternal(TokenCache.java:116)
> at
> org.apache.hadoop.mapreduce.security.TokenCache.obtainTokensForNamenodesInternal(TokenCache.java:100)
> at
> org.apache.hadoop.mapreduce.security.TokenCache.obtainTokensForNamenodes(TokenCache.java:80)
> at
> org.apache.hadoop.mapred.FileInputFormat.listStatus(FileInputFormat.java:205)
> at
> org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:313)
> at org.apache.spark.rdd.HadoopRDD.getPartitions(HadoopRDD.scala:202)
> {code}
> I have a workaround where I set a YARN-specific configuration variable to
> trick {{TokenCache}} into thinking YARN is configured, but this is obviously
> suboptimal.
> The proper fix to this would likely require significant {{hadoop}}
> refactoring to make split information available without going through
> {{JobConf}}, so I'm not yet sure what the best course of action is.
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