异常
Exception in thread "main" java.lang.NoClassDefFoundError: Could not initialize class org.apache.log4j.LogManager
at org.apache.log4j.Logger.getLogger(Logger.java:105)
at org.apache.sqoop.util.LoggingUtils.setDebugLevel(LoggingUtils.java:69)
at org.apache.sqoop.tool.BaseSqoopTool.applyCommonOptions(BaseSqoopTool.java:633)
at org.apache.sqoop.tool.ImportTool.applyOptions(ImportTool.java:713)
at org.apache.sqoop.tool.SqoopTool.parseArguments(SqoopTool.java:433)
at org.apache.sqoop.Sqoop.run(Sqoop.java:129)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:181)
at org.apache.sqoop.Sqoop.runTool(Sqoop.java:220)
at org.apache.sqoop.Sqoop.runTool(Sqoop.java:229)
at org.apache.sqoop.Sqoop.main(Sqoop.java:238)
at com.cloudera.sqoop.Sqoop.main(Sqoop.java:57)
Failing Oozie Launcher, Main class [org.apache.oozie.action.hadoop.ShellMain], exit code [1]
问题定位
单独执行Sqoop脚本没有问题，但通过oozie调用出现上述异常。
检查classpath，都有log4j的jar包。
分析单独执行和用oozie调用的脚本差别。
单独执行时，有个关键参数 -Dhadoop.root.logger=INFO,console
用oozie调用度时，生成的脚本 -Dhadoop.root.logger=INFO,TLA
检查log4j.properties，也有TLA的配置。
调试后发现是关键的参数-Dhadoop.tasklog.taskid缺少，这个与HADOOP_CLIENT_OPTS有关
问题解决
修改hadoop-env.sh
增加HADOOP_OPTS="-Djava.net.preferIPv4Stack=true $HADOOP_CLIENT_OPTS"来解决。