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https://issues.apache.org/jira/browse/SPARK-33212?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17240982#comment-17240982
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Apache Spark commented on SPARK-33212:
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User 'sunchao' has created a pull request for this issue:
https://github.com/apache/spark/pull/30556
> Move to shaded clients for Hadoop 3.x profile
> ---------------------------------------------
>
> Key: SPARK-33212
> URL: https://issues.apache.org/jira/browse/SPARK-33212
> Project: Spark
> Issue Type: Improvement
> Components: Spark Core, Spark Submit, SQL, YARN
> Affects Versions: 3.0.1
> Reporter: Chao Sun
> Assignee: Chao Sun
> Priority: Major
> Labels: releasenotes
> Fix For: 3.1.0
>
>
> Hadoop 3.x+ offers shaded client jars: hadoop-client-api and
> hadoop-client-runtime, which shade 3rd party dependencies such as Guava,
> protobuf, jetty etc. This Jira switches Spark to use these jars instead of
> hadoop-common, hadoop-client etc. Benefits include:
> * It unblocks Spark from upgrading to Hadoop 3.2.2/3.3.0+. The newer
> versions of Hadoop have migrated to Guava 27.0+ and in order to resolve Guava
> conflicts, Spark depends on Hadoop to not leaking dependencies.
> * It makes Spark/Hadoop dependency cleaner. Currently Spark uses both
> client-side and server-side Hadoop APIs from modules such as hadoop-common,
> hadoop-yarn-server-common etc. Moving to hadoop-client-api allows use to only
> use public/client API from Hadoop side.
> * Provides a better isolation from Hadoop dependencies. In future Spark can
> better evolve without worrying about dependencies pulled from Hadoop side
> (which used to be a lot).
> *There are some behavior changes introduced with this JIRA, when people use
> Spark compiled with Hadoop 3.x:*
> - Users now need to make sure class path contains `hadoop-client-api` and
> `hadoop-client-runtime` jars when they deploy Spark with the
> `hadoop-provided` option. In addition, it is high recommended that they put
> these two jars before other Hadoop jars in the class path. Otherwise,
> conflicts such as from Guava could happen if classes are loaded from the
> other non-shaded Hadoop jars.
> - Since the new shaded Hadoop clients no longer include 3rd party
> dependencies. Users who used to depend on these now need to explicitly put
> the jars in their class path.
> Ideally the above should go to release notes.
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