Oozie has several prebuilt actions. Some are listed below with their description:

$ cd ~
$ git clone git://github.com/edwardcapriolo/hive_test.git
$ cd hive_test
$ mvn wagon:download-single
$ mvn exec:exec
$ mvn install

$ cd ~
$ git clone git://github.com/edwardcapriolo/m6d_oozie.git
$ mvn install

A workflow is created by setting up a specific directory hierarchy with required JAR files, a job.properties file and a workflow.xml file. This hierarchy has to be stored in HDFS, but it is best to assemble the folder locally and then copy it to HDFS:

$ mkdir myapp
$ mkdir myapp/lib
$ cp $HIVE_HOME/lib/*.jar myapp/lib/
$ cp m6d_oozie-1.0.0.jar myapp/lib/
$ cp hive_test-4.0.0.jar myapp/lib/

The job.properties sets the name of the filesystem and the JobTracker. Also, additional properties can be set here to be used as Hadoop Job Configuration properties:

The job.properties file:

nameNode=hdfs://rs01.hadoop.pvt:34310
jobTracker=rjt.hadoop.pvt:34311
queueName=default
oozie.libpath=/user/root/oozie/test/lib
oozie.wf.application.path=${nameNode}/user/root/oozie/test/main

The workflow.xml is the file where actions are defined:

<workflow-app xmlns="uri:oozie:workflow:0.2" name="java-main-wf">
    <start to="create-node"/>
    <!--The create-node actual defines a table if it does not
    already exist-->
    <action name="create-node">
        <java>
            <job-tracker>${jobTracker}</job-tracker>
            <name-node>${nameNode}</name-node>
            <configuration>
                <property>
                    <name>mapred.job.queue.name</name>
                    <value>${queueName}</value>
                </property>
            </configuration>
            <main-class>com.m6d.oozie.HiveServiceBAction</main-class>
            <arg>rhiveservice.hadoop.pvt</arg>
            <arg>10000</arg>
            <arg>CREATE TABLE IF NOT EXISTS zz_zz_abc (a int, b int)</arg>
        </java>
        <!-- on success proceded to query_node action -->
        <ok to="query_node"/>
        <!-- on fail end the job unsuccessfully-->
        <error to="fail"/>
    </action>

    <!-- populate the contents of the table with an
    insert overwrite query -->
    <action name="query_node">
       <java>
            <job-tracker>${jobTracker}</job-tracker>
            <name-node>${nameNode}</name-node>
            <configuration>
                <property>
                    <name>mapred.job.queue.name</name>
                    <value>${queueName}</value>
                </property>
            </configuration>
            <main-class>com.m6d.oozie.HiveServiceBAction</main-class>
            <arg>rhiveservice.hadoop.pvt</arg>
            <arg>10000</arg>
            <arg>INSERT OVERWRITE TABLE zz_zz_abc SELECT dma_code,site_id
        FROM BCO WHERE dt=20120426 AND offer=4159 LIMIT 10</arg>
        </java>
        <ok to="end"/>
        <error to="fail"/>
    </action>

    <kill name="fail">
        <message>Java failed, error message
        [${wf:errorMessage(wf:lastErrorNode())}]</message>
    </kill>
    <end name="end"/>
</workflow-app>

The Oozie web console is helpful for troubleshooting jobs. Oozie launches each action inside a map task and captures all the input and output. Oozie does a good job presenting this information as well as providing links to job status pages found on the Hadoop JobTracker web console.

Here is a screenshot of the Oozie web console.

A workflow based on completely static queries is useful but not overly practical. Most of the use cases for Oozie run a series of processes against files for today or this week. In the previous workflow, you may have noticed the KILL tag and the interpolated variable inside of it:

<kill name="fail">
  <message>Java failed, error message
    [${wf:errorMessage(wf:lastErrorNode())}]</message>
</kill>

Oozie provides an ETL to access variables. Key-value pairs defined in job.properties can be referenced this way.

Oozie also has a tag <captureOutput/> that can be placed inside an action. Output captured can be emailed with an error or sent to another process. Oozie sets a Java property in each action that can be used as a filename to write output to. The code below shows how this property is accessed:

private static final String
OOZIE_ACTION_OUTPUT_PROPERTIES = "oozie.action.output.properties";

public static void main(String args[]) throws Exception {
  String oozieProp = System.getProperty(OOZIE_ACTION_OUTPUT_PROPERTIES);
}

Your application can output data to that location.

We have discussed both capturing output and Oozie variables; using them together provides what you need for daily workflows.

Looking at our previous example, we see that we are selecting data from a hardcoded day FROM BCO WHERE dt=20120426. We would like to run this workflow every day so we need to substitute the hardcoded dt=20120426 with a date:

<action name="create_table">
    <java>
        <job-tracker>${jobTracker}</job-tracker>
        <name-node>${nameNode}</name-node>
        <configuration>
            <property>
                <name>mapred.job.queue.name</name>
                <value>${queueName}</value>
            </property>
        </configuration>
        <main-class>test.RunShellProp</main-class>
        <arg>/bin/date</arg>
        <arg>+x=%Y%m%d</arg>
        <capture-output />
    </java>
    <ok to="run_query"/>
    <error to="fail"/>
</action>

This will produce output like:

$ date +x=%Y%m%d
x=20120522

You can then access this output later in the process:

<arg>You said ${wf:actionData('create_table')['x']}</arg>

There are many more things you can do with Oozie, including integrating Hive jobs with jobs implemented with other tools, such as Pig, Java MapReduce, etc. See the Oozie website for more details.