HiveOnTez: 包冲突问题排查思路

执行tez报错，观察YARN日志，Driver端报错为：File does not exist: hdfs://lt-nameservice3.sy/tmp/hive/app/_tez_session_dir/09ff9062-cc3e-4cb3-bc8d-77c275266d94/.tez/application_1528552108294_273009/tez.session.local-resources.pb java.io.FileNotFoundException

此时进入ApplicationMaster的log观察，根本报错内容如下，显然为guava包冲突导致（guava21以上会移除一些method接口不再向前兼容）。

Caused by: java.lang.NoSuchMethodError: com.google.common.base.Objects.toStringHelper(Ljava/lang/Object;)Lcom/google/common/base/Objects$ToStringHelper;

at org.apache.hadoop.metrics2.lib.MetricsRegistry.toString(MetricsRegistry.java:406)

at java.lang.String.valueOf(String.java:2994)

at java.lang.StringBuilder.append(StringBuilder.java:131)

at org.apache.hadoop.ipc.metrics.RpcMetrics.<init>(RpcMetrics.java:74)

at org.apache.hadoop.ipc.metrics.RpcMetrics.create(RpcMetrics.java:80)

at org.apache.hadoop.ipc.Server.<init>(Server.java:2213)

at org.apache.hadoop.ipc.RPC$Server.<init>(RPC.java:1029)

at org.apache.hadoop.ipc.ProtobufRpcEngine$Server.<init>(ProtobufRpcEngine.java:537)

at org.apache.hadoop.ipc.ProtobufRpcEngine.getServer(ProtobufRpcEngine.java:512)

at org.apache.hadoop.ipc.RPC$Builder.build(RPC.java:874)

at org.apache.tez.dag.api.client.DAGClientServer.createServer(DAGClientServer.java:127)

at org.apache.tez.dag.api.client.DAGClientServer.serviceStart(DAGClientServer.java:79)

at org.apache.hadoop.service.AbstractService.start(AbstractService.java:193)

at org.apache.tez.dag.app.DAGAppMaster$ServiceWithDependency.start(DAGAppMaster.java:1838)

at org.apache.tez.dag.app.DAGAppMaster$ServiceThread.run(DAGAppMaster.java:1859)

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科普下Driver日志和ApplicationMaster日志查看位置：

如图，从YARN页面点击application id进入的页面为Driver页面，红框内容为Driver端报错信息；点击蓝框才会进入ApplicationMaster日志。

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此时，在ApplicationMaster中搜索java.class.path可以拿到当前am环境下的所有classpath，从url中获取当前am所在节点，把所有jar包拉出来，找下包版本冲突所在jar包即可。如果为自己jar包里的dependency冲突，或shade，或exclude即可解决。

相关命令如下：

jar -tf platform_udf-1.0-SNAPSHOT.jar | grep -i com.google.common

javap -classpath platform_udf-1.0-SNAPSHOT.jar com.google.common.base.Objects