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https://issues.apache.org/jira/browse/HBASE-15686?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15253150#comment-15253150
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Jerry He commented on HBASE-15686:
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Hi, [~sjlee0]
bq. allow configuring the exempt classes
This is interesting.
But HBase already tries to put 'minimum' in the exempt list (classes that need
to be loaded from system classpath), meaning anything less would cause problem
for HBase.
For example, there is class casting between the host and co-processor.
In the 2.0 version, the only thing meaningful in the exempt list is native
hbase.
> unable to dynamically load a table coprocessor if it belongs in
> org.apache.hadoop
> ---------------------------------------------------------------------------------
>
> Key: HBASE-15686
> URL: https://issues.apache.org/jira/browse/HBASE-15686
> Project: HBase
> Issue Type: Bug
> Components: Coprocessors
> Affects Versions: 1.0.1
> Reporter: Sangjin Lee
>
> As part of Hadoop's Timeline Service v.2 (YARN-2928), we're adding a table
> coprocessor (YARN-4062). However, we're finding that the coprocessor cannot
> be loaded dynamically. A relevant snippet for the exception:
> {noformat}
> java.io.IOException: Class
> org.apache.hadoop.yarn.server.timelineservice.storage.flow.FlowRunCoprocessor
> cannot be loaded
> at
> org.apache.hadoop.hbase.master.HMaster.sanityCheckTableDescriptor(HMaster.java:1329)
> at org.apache.hadoop.hbase.master.HMaster.createTable(HMaster.java:1269)
> at
> org.apache.hadoop.hbase.master.MasterRpcServices.createTable(MasterRpcServices.java:398)
> at
> org.apache.hadoop.hbase.protobuf.generated.MasterProtos$MasterService$2.callBlockingMethod(MasterProtos.java:42436)
> at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2031)
> at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:107)
> at
> org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:130)
> at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:107)
> at java.lang.Thread.run(Thread.java:745)
> Caused by: java.io.IOException: Class
> org.apache.hadoop.yarn.server.timelineservice.storage.flow.FlowRunCoprocessor
> cannot be loaded
> at
> org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost.testTableCoprocessorAttrs(RegionCoprocessorHost.java:324)
> at
> org.apache.hadoop.hbase.master.HMaster.checkClassLoading(HMaster.java:1483)
> at
> org.apache.hadoop.hbase.master.HMaster.sanityCheckTableDescriptor(HMaster.java:1327)
> ... 8 more
> Caused by: java.lang.ClassNotFoundException:
> org.apache.hadoop.yarn.server.timelineservice.storage.flow.FlowRunCoprocessor
> at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
> at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
> at java.security.AccessController.doPrivileged(Native Method)
> at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
> at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
> at
> org.apache.hadoop.hbase.util.CoprocessorClassLoader.loadClass(CoprocessorClassLoader.java:275)
> at
> org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost.testTableCoprocessorAttrs(RegionCoprocessorHost.java:322)
> ... 10 more
> {noformat}
> We tracked it down to the fact that {{CoprocessorClassLoader}} regarding all
> hadoop classes as exempt from loading from the coprocessor jar. Since our
> coprocessor sits in the coprocessor jar, and yet the loading of this class is
> delegated to the parent which does not have this jar, the classloading fails.
> What would be nice is the ability to exclude certain classes from the exempt
> classes so that they can be loaded via table coprocessor classloader. See
> hadoop's {{ApplicationClassLoader}} for a similar feature.
> Is there any other way to load this coprocessor at the table scope?
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