oozie安装目录下，oozie-examples.tar.gz 中存在一些案例。
解压到当前目录，并查看。创建oozie-apps目录，保存测试示例。

  1. $ tar -zxf oozie-examples.tar.gz
  2. $ cd examples/
  3. $ ls
  4. apps  input-data  src
  5. $ ls apps
  6. aggregator  cron           custom-main         demo    hadoop-el  hive       map-reduce  pig    sla    sqoop-freeform  streaming
  7. bundle      cron-schedule  datelist-java-main  distcp  hcatalog   java-main  no-op       shell  sqoop  ssh             subwf
  8. $ cd ..
  9. $ mkdir oozie-apps

调度MR任务 - oozie示例

使用 oozie 自带示例 examples/apps/map-reduce 及数据文件 examples/input-data ，复制到 oozie-apps 中，并修改配置文件。

  1. $ cp -r examples/apps/map-reduce oozie-apps/map-reduce
  2. $ cp -r examples/input-data oozie-apps/input-data
  3. $ ls oozie-apps/map-reduce/
  4. job.properties  job-with-config-class.properties  lib  
  5. workflow-with-config-class.xml  workflow.xml
  6. $ ls oozie-apps/map-reduce/lib
  7. oozie-examples-4.0.0-cdh5.3.6.jar

job.properties

  1. nameNode=hdfs://192.168.32.130:8020
  2. # yarn.resourcemanager.address  ${yarn.resourcemanager.hostname}:8032
  3. jobTracker=192.168.32.130:8032
  4. queueName=default
  5. examplesRoot=oozie-apps
  7. # 执行应用程序路径 hdfs://192.168.32.130:8020/user/jack/oozie-apps/map-reduce/workflow.xml
  8. oozie.wf.application.path=${nameNode}/user/${user.name}/${examplesRoot}/map-reduce/workflow.xml
  9. outputDir=map-reduce

workflow.xml

  1. <workflow-app xmlns="uri:oozie:workflow:0.2" name="map-reduce-wf">
  2.     <start to="mr-node"/>
  3.     <action name="mr-node">
  4.         <map-reduce>
  5.             <job-tracker>${jobTracker}</job-tracker>
  6.             <name-node>${nameNode}</name-node>
  7.             <prepare>
  8.                 <delete path="${nameNode}/user/${wf:user()}/${examplesRoot}/output-data/${outputDir}"/>
  9.             </prepare>
  10.             <configuration>
  11.                 <property>
  12.                     <name>mapred.job.queue.name</name>
  13.                     <value>${queueName}</value>
  14.                 </property>
  15.                 <property>
  16.                     <name>mapred.mapper.class</name>
  17.                     <value>org.apache.oozie.example.SampleMapper</value>
  18.                 </property>
  19.                 <property>
  20.                     <name>mapred.reducer.class</name>
  21.                     <value>org.apache.oozie.example.SampleReducer</value>
  22.                 </property>
  23.                 <property>
  24.                     <name>mapred.map.tasks</name>
  25.                     <value>1</value>
  26.                 </property>
  27.                 <property>
  28.                     <name>mapred.input.dir</name>
  29.                     <value>/user/${wf:user()}/${examplesRoot}/input-data/text</value>
  30.                 </property>
  31.                 <property>
  32.                     <name>mapred.output.dir</name>
  33.                     <value>/user/${wf:user()}/${examplesRoot}/output-data/${outputDir}</value>
  34.                 </property>
  35.             </configuration>
  36.         </map-reduce>
  37.         <ok to="end"/>
  38.         <error to="fail"/>
  39.     </action>
  40.     <kill name="fail">
  41.         <message>Map/Reduce failed, error message[${wf:errorMessage(wf:lastErrorNode())}]</message>
  42.     </kill>
  43.     <end name="end"/>
  44. </workflow-app>

prepare 元素，指定该节点任务的准备条件，

属性 mapred.mapper.class 和 mapred.reducer.class 的值，指向的 class ，放置在该工作目录下的 lib 中，以 jar 包的形式保存（oozie-examples-4.0.0-cdh5.3.6.jar）。

这些类的实现源码，在 examples/src 目录下。

属性 mapred.input.dir 和 mapred.output.dir 的值，表示MapReduce程序的输入输出目录位置。输入数据在 examples/input-data 目录中，需上传到指定位置 /user/jack/oozie-apps/ 下。

SampleMapper.java

使用的是旧式API

  1. /**
  2.  * Licensed to the Apache Software Foundation (ASF) under one
  3.  * or more contributor license agreements.  See the NOTICE file
  4.  * distributed with this work for additional information
  5.  * regarding copyright ownership.  The ASF licenses this file
  6.  * to you under the Apache License, Version 2.0 (the
  7.  * "License"); you may not use this file except in compliance
  8.  * with the License.  You may obtain a copy of the License at
  9.  * 
  10.  *      http://www.apache.org/licenses/LICENSE-2.0
  11.  * 
  12.  * Unless required by applicable law or agreed to in writing, software
  13.  * distributed under the License is distributed on an "AS IS" BASIS,
  14.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15.  * See the License for the specific language governing permissions and
  16.  * limitations under the License.
  17.  */
  18. package org.apache.oozie.example;
  20. import org.apache.hadoop.io.LongWritable;
  21. import org.apache.hadoop.io.Text;
  22. import org.apache.hadoop.mapred.JobConf;
  23. import org.apache.hadoop.mapred.Mapper;
  24. import org.apache.hadoop.mapred.OutputCollector;
  25. import org.apache.hadoop.mapred.Reporter;
  27. import java.io.IOException;
  29. public class SampleMapper implements Mapper<LongWritable, Text, LongWritable, Text> {
  31.     public void configure(JobConf jobConf) {
  32.     }
  34.     public void map(LongWritable key, Text value, 
  35.                     OutputCollector<LongWritable, Text> collector, Reporter reporter)
  36.             throws IOException {
  37.         // 字节偏移量，行文本
  38.         collector.collect(key, value);
  39.     }
  41.     public void close() throws IOException {
  42.     }
  44. }

SampleReducer.java

  1. /**
  2.  * Licensed to the Apache Software Foundation (ASF) under one
  3.  * or more contributor license agreements.  See the NOTICE file
  4.  * distributed with this work for additional information
  5.  * regarding copyright ownership.  The ASF licenses this file
  6.  * to you under the Apache License, Version 2.0 (the
  7.  * "License"); you may not use this file except in compliance
  8.  * with the License.  You may obtain a copy of the License at
  9.  * 
  10.  *      http://www.apache.org/licenses/LICENSE-2.0
  11.  * 
  12.  * Unless required by applicable law or agreed to in writing, software
  13.  * distributed under the License is distributed on an "AS IS" BASIS,
  14.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15.  * See the License for the specific language governing permissions and
  16.  * limitations under the License.
  17.  */
  18. package org.apache.oozie.example;
  20. import org.apache.hadoop.io.LongWritable;
  21. import org.apache.hadoop.io.Text;
  22. import org.apache.hadoop.mapred.JobConf;
  23. import org.apache.hadoop.mapred.OutputCollector;
  24. import org.apache.hadoop.mapred.Reducer;
  25. import org.apache.hadoop.mapred.Reporter;
  27. import java.io.IOException;
  28. import java.util.Iterator;
  30. public class SampleReducer implements Reducer<LongWritable, Text, LongWritable, Text> {
  32.     public void configure(JobConf jobConf) {
  33.     }
  35.     public void reduce(LongWritable key, Iterator<Text> values, OutputCollector<LongWritable, Text> collector, Reporter reporter)
  36.             throws IOException {
  37.         // 循环输出，不作处理
  38.         while (values.hasNext()) {
  39.             collector.collect(key, values.next());
  40.         }
  41.     }
  43.     public void close() throws IOException {
  44.     }
  46. }

执行 job.properties

  1. $ ~/Documents/hadoop/bin/hadoop fs -put oozie-apps/input-data oozie-apps/input-data
  2. $ ~/Documents/hadoop/bin/hadoop fs -put oozie-apps/map-reduce/* oozie-apps/map-reduce
  3. $ ~/Documents/hadoop/bin/hadoop fs -ls oozie-apps/map-reduce
  4. Found 5 items
  5. -rw-r--r--   1 jack supergroup       1028 2020-04-21 05:59 oozie-apps/map-reduce/job-with-config-class.properties
  6. -rw-r--r--   1 jack supergroup       1019 2020-04-21 05:59 oozie-apps/map-reduce/job.properties
  7. drwxr-xr-x   - jack supergroup          0 2020-04-21 05:59 oozie-apps/map-reduce/lib
  8. -rw-r--r--   1 jack supergroup       2274 2020-04-21 05:59 oozie-apps/map-reduce/workflow-with-config-class.xml
  9. -rw-r--r--   1 jack supergroup       2559 2020-04-21 05:59 oozie-apps/map-reduce/workflow.xml
  11. $ # 执行任务
  12. $ export OOZIE_URL="http://192.168.32.130:11000/oozie"
  13. $ bin/oozie job -config oozie-apps/map-reduce/job.properties -run
  14. job: 0000007-200420185350972-oozie-jack-W
  15. $ bin/oozie job -info 0000007-200420185350972-oozie-jack-W
  16. Job ID : 0000007-200420185350972-oozie-jack-W
  17. ------------------------------------------------------------------------------------------------------------------------------------
  18. Workflow Name : map-reduce-wf
  19. App Path      : hdfs://192.168.32.130:8020/user/jack/oozie-apps/map-reduce/workflow.xml
  20. Status        : SUCCEEDED
  21. Run           : 0
  22. User          : jack
  23. Group         : -
  24. Created       : 2020-04-21 13:00 GMT
  25. Started       : 2020-04-21 13:00 GMT
  26. Last Modified : 2020-04-21 13:01 GMT
  27. Ended         : 2020-04-21 13:01 GMT
  28. CoordAction ID: -
  30. Actions
  31. ------------------------------------------------------------------------------------------------------------------------------------
  32. ID                                                                            Status    Ext ID                 Ext Status Err Code  
  33. ------------------------------------------------------------------------------------------------------------------------------------
  34. 0000007-200420185350972-oozie-jack-W@:start:                                  OK        -                      OK         -         
  35. ------------------------------------------------------------------------------------------------------------------------------------
  36. 0000007-200420185350972-oozie-jack-W@mr-node                                  OK        job_1586921478592_0029 SUCCEEDED  -         
  37. ------------------------------------------------------------------------------------------------------------------------------------
  38. 0000007-200420185350972-oozie-jack-W@end                                      OK        -                      OK         -         
  39. ------------------------------------------------------------------------------------------------------------------------------------
  40. $ ~/Documents/hadoop/bin/hadoop fs -ls oozie-apps/output-data/map-reduce
  41. Found 2 items
  42. -rw-r--r--   1 jack supergroup          0 2020-04-21 06:01 oozie-apps/output-data/map-reduce/_SUCCESS
  43. -rw-r--r--   1 jack supergroup       1547 2020-04-21 06:01 oozie-apps/output-data/map-reduce/part-00000
  45. $ # 默认Map处理，Reduce不作处理
  46. $ ~/Documents/hadoop/bin/hadoop fs -cat oozie-apps/output-data/map-reduce/*
  47. 0       To be or not to be, that is the question;
  48. 42      Whether 'tis nobler in the mind to suffer
  49. 84      The slings and arrows of outrageous fortune,
  50. 129     Or to take arms against a sea of troubles,
  51. 172     And by opposing, end them. To die, to sleep;
  52. 217     No more; and by a sleep to say we end
  53. 255     The heart-ache and the thousand natural shocks
  54. 302     That flesh is heir to ? 'tis a consummation
  55. 346     Devoutly to be wish'd. To die, to sleep;
  56. 387     To sleep, perchance to dream. Ay, there's the rub,
  57. 438     For in that sleep of death what dreams may come,
  58. 487     When we have shuffled off this mortal coil,
  59. 531     Must give us pause. There's the respect
  60. 571     That makes calamity of so long life,
  61. 608     For who would bear the whips and scorns of time,
  62. 657     Th'oppressor's wrong, the proud man's contumely,
  63. 706     The pangs of despised love, the law's delay,
  64. 751     The insolence of office, and the spurns
  65. 791     That patient merit of th'unworthy takes,
  66. 832     When he himself might his quietus make
  67. 871     With a bare bodkin? who would fardels bear,
  68. 915     To grunt and sweat under a weary life,
  69. 954     But that the dread of something after death,
  70. 999     The undiscovered country from whose bourn
  71. 1041    No traveller returns, puzzles the will,
  72. 1081    And makes us rather bear those ills we have
  73. 1125    Than fly to others that we know not of?
  74. 1165    Thus conscience does make cowards of us all,
  75. 1210    And thus the native hue of resolution
  76. 1248    Is sicklied o'er with the pale cast of thought,
  77. 1296    And enterprises of great pitch and moment
  78. 1338    With this regard their currents turn awry,
  79. 1381    And lose the name of action.

job-with-config-class.properties

  1. nameNode=hdfs://192.168.32.130:8020
  2. jobTracker=192.168.32.130:8032
  3. queueName=default
  4. examplesRoot=oozie-apps
  6. oozie.wf.application.path=${nameNode}/user/${user.name}/${examplesRoot}/map-reduce/workflow-with-config-class.xml
  7. outputDir=map-reduce

workflow-with-config-class.xml

  1. <workflow-app xmlns="uri:oozie:workflow:0.5" name="map-reduce-wf">
  2.     <start to="mr-node"/>
  3.     <action name="mr-node">
  4.         <map-reduce>
  5.             <job-tracker>${jobTracker}</job-tracker>
  6.             <name-node>${nameNode}</name-node>
  7.             <prepare>
  8.                 <delete path="${nameNode}/user/${wf:user()}/${examplesRoot}/output-data/${outputDir}"/>
  9.             </prepare>
  10.             <!-- most of the <configuration> properties are being set by SampleOozieActionConfigurator -->
  11.             <configuration>
  12.                 <property>
  13.                     <name>mapred.job.queue.name</name>
  14.                     <value>${queueName}</value>
  15.                 </property>
  16.                 <!-- These two are not Hadoop properties, but SampleOozieActionConfigurator can use them -->
  17.                 <property>
  18.                     <name>examples.root</name>
  19.                     <value>${examplesRoot}</value>
  20.                 </property>
  21.                 <property>
  22.                     <name>output.dir.name</name>
  23.                     <value>${outputDir}</value>
  24.                 </property>
  25.             </configuration>
  26.             <config-class>org.apache.oozie.example.SampleOozieActionConfigurator</config-class>
  27.         </map-reduce>
  28.         <ok to="end"/>
  29.         <error to="fail"/>
  30.     </action>
  31.     <kill name="fail">
  32.         <message>Map/Reduce failed, error message[${wf:errorMessage(wf:lastErrorNode())}]</message>
  33.     </kill>
  34.     <end name="end"/>
  35. </workflow-app>

与 workflow.xml 的差异，通过 config-class 元素来统一配置，该元素引用的class类，引用配置类 org.apache.oozie.example.SampleOozieActionConfigurator 。

该类的实现源码，在 examples/src 目录下。

SampleOozieActionConfigurator.java

  1. /**
  2.  * Licensed to the Apache Software Foundation (ASF) under one
  3.  * or more contributor license agreements.  See the NOTICE file
  4.  * distributed with this work for additional information
  5.  * regarding copyright ownership.  The ASF licenses this file
  6.  * to you under the Apache License, Version 2.0 (the
  7.  * "License"); you may not use this file except in compliance
  8.  * with the License.  You may obtain a copy of the License at
  9.  *
  10.  *      http://www.apache.org/licenses/LICENSE-2.0
  11.  *
  12.  * Unless required by applicable law or agreed to in writing, software
  13.  * distributed under the License is distributed on an "AS IS" BASIS,
  14.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15.  * See the License for the specific language governing permissions and
  16.  * limitations under the License.
  17.  */
  18. package org.apache.oozie.example;
  20. import org.apache.hadoop.fs.Path;
  21. import org.apache.hadoop.mapred.FileInputFormat;
  22. import org.apache.hadoop.mapred.FileOutputFormat;
  23. import org.apache.hadoop.mapred.JobConf;
  24. import org.apache.oozie.action.hadoop.OozieActionConfigurator;
  25. import org.apache.oozie.action.hadoop.OozieActionConfiguratorException;
  27. public class SampleOozieActionConfigurator implements OozieActionConfigurator {
  29.     @Override
  30.     public void configure(JobConf actionConf) throws OozieActionConfiguratorException {
  31.         if (actionConf.getUser() == null) {
  32.             throw new OozieActionConfiguratorException("No user set");
  33.         }
  34.         if (actionConf.get("examples.root") == null) {
  35.             throw new OozieActionConfiguratorException("examples.root not set");
  36.         }
  37.         if (actionConf.get("output.dir.name") == null) {
  38.             throw new OozieActionConfiguratorException("output.dir.name not set");
  39.         }
  41.         actionConf.setMapperClass(SampleMapper.class);
  42.         actionConf.setReducerClass(SampleReducer.class);
  43.         actionConf.setNumMapTasks(1);
  44.         FileInputFormat.setInputPaths(actionConf,
  45.                 new Path("/user/" + actionConf.getUser() + "/" 
  46.                          + actionConf.get("examples.root") + "/input-data/text"));
  47.         FileOutputFormat.setOutputPath(actionConf,
  48.                 new Path("/user/" + actionConf.getUser() + "/" 
  49.                          + actionConf.get("examples.root") + "/output-data/"
  50.                          + actionConf.get("output.dir.name")));
  51.     }
  52. }

该 OozieActionConfigurator 接口的实现类，定义了 Mapper类、Reducer类、Map任务数、输入目录和输出目录。

执行 job-with-config-class.properties

  1. $ # 更新 job-with-config-class.properties
  2. $ ~/Documents/hadoop/bin/hadoop fs -put -f oozie-apps/map-reduce/job-with-config-class.properties oozie-apps/map-reduce/
  3. $ ~/Documents/hadoop/bin/hadoop fs -ls oozie-apps/map-reduce
  4. Found 5 items
  5. -rw-r--r--   1 jack supergroup       1028 2020-04-21 18:14 oozie-apps/map-reduce/job-with-config-class.properties
  6. -rw-r--r--   1 jack supergroup       1019 2020-04-21 05:59 oozie-apps/map-reduce/job.properties
  7. drwxr-xr-x   - jack supergroup          0 2020-04-21 05:59 oozie-apps/map-reduce/lib
  8. -rw-r--r--   1 jack supergroup       2274 2020-04-21 05:59 oozie-apps/map-reduce/workflow-with-config-class.xml
  9. -rw-r--r--   1 jack supergroup       2559 2020-04-21 05:59 oozie-apps/map-reduce/workflow.xml
  11. $ # 执行任务
  12. $ export OOZIE_URL="http://192.168.32.130:11000/oozie"
  13. $ bin/oozie job -config oozie-apps/map-reduce/job.properties -run
  14. job: 0000008-200420185350972-oozie-jack-W
  15. $ bin/oozie job -info 0000008-200420185350972-oozie-jack-W
  16. Job ID : 0000008-200420185350972-oozie-jack-W
  17. ------------------------------------------------------------------------------------------------------------------------------------
  18. Workflow Name : map-reduce-wf
  19. App Path      : hdfs://192.168.32.130:8020/user/jack/oozie-apps/map-reduce/workflow-with-config-class.xml
  20. Status        : RUNNING
  21. Run           : 0
  22. User          : jack
  23. Group         : -
  24. Created       : 2020-04-22 01:18 GMT
  25. Started       : 2020-04-22 01:18 GMT
  26. Last Modified : 2020-04-22 01:18 GMT
  27. Ended         : -
  28. CoordAction ID: -
  30. Actions
  31. ------------------------------------------------------------------------------------------------------------------------------------
  32. ID                                                                            Status    Ext ID                 Ext Status Err Code  
  33. ------------------------------------------------------------------------------------------------------------------------------------
  34. 0000008-200420185350972-oozie-jack-W@:start:                                  OK        -                      OK         -         
  35. ------------------------------------------------------------------------------------------------------------------------------------
  36. 0000008-200420185350972-oozie-jack-W@mr-node                                  RUNNING   job_1586921478592_0031 RUNNING    -         
  37. ------------------------------------------------------------------------------------------------------------------------------------
  38. [jack@master oozie]$ bin/oozie job -info 0000008-200420185350972-oozie-jack-W
  39. Job ID : 0000008-200420185350972-oozie-jack-W
  40. ------------------------------------------------------------------------------------------------------------------------------------
  41. Workflow Name : map-reduce-wf
  42. App Path      : hdfs://192.168.32.130:8020/user/jack/oozie-apps/map-reduce/workflow-with-config-class.xml
  43. Status        : SUCCEEDED
  44. Run           : 0
  45. User          : jack
  46. Group         : -
  47. Created       : 2020-04-22 01:18 GMT
  48. Started       : 2020-04-22 01:18 GMT
  49. Last Modified : 2020-04-22 01:19 GMT
  50. Ended         : 2020-04-22 01:19 GMT
  51. CoordAction ID: -
  53. Actions
  54. ------------------------------------------------------------------------------------------------------------------------------------
  55. ID                                                                            Status    Ext ID                 Ext Status Err Code  
  56. ------------------------------------------------------------------------------------------------------------------------------------
  57. 0000008-200420185350972-oozie-jack-W@:start:                                  OK        -                      OK         -         
  58. ------------------------------------------------------------------------------------------------------------------------------------
  59. 0000008-200420185350972-oozie-jack-W@mr-node                                  OK        job_1586921478592_0031 SUCCEEDED  -         
  60. ------------------------------------------------------------------------------------------------------------------------------------
  61. 0000008-200420185350972-oozie-jack-W@end                                      OK        -                      OK         -         
  62. ------------------------------------------------------------------------------------------------------------------------------------
  64. $ ~/Documents/hadoop/bin/hadoop fs -ls oozie-apps/output-data/map-reduce
  65. Found 2 items
  66. -rw-r--r--   1 jack supergroup          0 2020-04-21 18:18 oozie-apps/output-data/map-reduce/_SUCCESS
  67. -rw-r--r--   1 jack supergroup       1547 2020-04-21 18:18 oozie-apps/output-data/map-reduce/part-00000
  69. $ # 默认Map处理，Reduce不作处理
  70. $ ~/Documents/hadoop/bin/hadoop fs -cat oozie-apps/output-data/map-reduce/*
  71. 0       To be or not to be, that is the question;
  72. 42      Whether 'tis nobler in the mind to suffer
  73. 84      The slings and arrows of outrageous fortune,
  74. 129     Or to take arms against a sea of troubles,
  75. 172     And by opposing, end them. To die, to sleep;
  76. 217     No more; and by a sleep to say we end
  77. 255     The heart-ache and the thousand natural shocks
  78. 302     That flesh is heir to ? 'tis a consummation
  79. 346     Devoutly to be wish'd. To die, to sleep;
  80. 387     To sleep, perchance to dream. Ay, there's the rub,
  81. 438     For in that sleep of death what dreams may come,
  82. 487     When we have shuffled off this mortal coil,
  83. 531     Must give us pause. There's the respect
  84. 571     That makes calamity of so long life,
  85. 608     For who would bear the whips and scorns of time,
  86. 657     Th'oppressor's wrong, the proud man's contumely,
  87. 706     The pangs of despised love, the law's delay,
  88. 751     The insolence of office, and the spurns
  89. 791     That patient merit of th'unworthy takes,
  90. 832     When he himself might his quietus make
  91. 871     With a bare bodkin? who would fardels bear,
  92. 915     To grunt and sweat under a weary life,
  93. 954     But that the dread of something after death,
  94. 999     The undiscovered country from whose bourn
  95. 1041    No traveller returns, puzzles the will,
  96. 1081    And makes us rather bear those ills we have
  97. 1125    Than fly to others that we know not of?
  98. 1165    Thus conscience does make cowards of us all,
  99. 1210    And thus the native hue of resolution
  100. 1248    Is sicklied o'er with the pale cast of thought,
  101. 1296    And enterprises of great pitch and moment
  102. 1338    With this regard their currents turn awry,
  103. 1381    And lose the name of action.

WordCount示例

示例位置 hadoop/share/hadoop/mapreduce2/hadoop-mapreduce-examples-2.5.0-cdh5.3.6.jar ，放入lib目录下，修改 job.properties 和 workflow.xml 文件，并执行。

workflow.xml

  1. <workflow-app xmlns="uri:oozie:workflow:0.2" name="map-reduce-wf">
  2.     <start to="mr-node"/>
  3.     <action name="mr-node">
  4.         <map-reduce>
  5.             <job-tracker>${jobTracker}</job-tracker>
  6.             <name-node>${nameNode}</name-node>
  7.             <prepare>
  8.                 <delete path="${nameNode}/user/${wf:user()}/${examplesRoot}/output-data/${outputDir}"/>
  9.             </prepare>
  10.             <configuration>
  11.                 <property>
  12.                     <name>mapred.job.queue.name</name>
  13.                     <value>${queueName}</value>
  14.                 </property>
  15.                 <property>
  16.                     <name>mapred.mapper.class</name>
  17.                     <value>org.apache.hadoop.examples.WordCount$TokenizerMapper</value>
  18.                 </property>
  19.                 <property>
  20.                     <name>mapred.reducer.class</name>
  21.                     <value>org.apache.hadoop.examples.WordCount$IntSumReducer</value>
  22.                 </property>
  23.                 <property>
  24.                     <name>mapred.map.tasks</name>
  25.                     <value>1</value>
  26.                 </property>
  27.                 <property>
  28.                     <name>mapred.input.dir</name>
  29.                     <value>/user/${wf:user()}/${examplesRoot}/input-data/text</value>
  30.                 </property>
  31.                 <property>
  32.                     <name>mapred.output.dir</name>
  33.                     <value>/user/${wf:user()}/${examplesRoot}/output-data/${outputDir}</value>
  34.                 </property>
  35.             </configuration>
  36.         </map-reduce>
  37.         <ok to="end"/>
  38.         <error to="fail"/>
  39.     </action>
  40.     <kill name="fail">
  41.         <message>Map/Reduce failed, error message[${wf:errorMessage(wf:lastErrorNode())}]</message>
  42.     </kill>
  43.     <end name="end"/>
  44. </workflow-app>

WordCount 的内部类，编译成jar包，org.apache.hadoop.examples.WordCount$IntSumReducer.class 和 org.apache.hadoop.examples.WordCount$TokenizerMapper.class 是编译之后的class导入名称，符号 $ 后的类是前面的类的内部类。