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Getting Started with Hama on YARN

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Preparations

Current Hama and Hadoop requires JRE 1.6 7 or higher and ssh to be set up between nodes in the cluster:

• Hadoop-2.x
• Sun Java JDK 1.6.x 7 or higher version
  

For additional information consult our CompatibilityTable.

This tutorial requires Hadoop 2.x already correctly installed. If you haven't done this yet, please follow the official documentation https://hadoop.apache.org/docs/stable/

Configuration

Only two properties which are resource manager address and default filesystem uri is essentially needed for Hama on YARN. The sample configuration is as follows:

<!-- Path to your hama-site.xml -->
<configuration>
    <property>
        <name>yarn.resourcemanager.address</name>
        <value>'your resource manager address or hostname':'resource manager port'</value>
    </property>
    <property>
        <name>fs.default.name</name>
        <value>hdfs://'your default file system address or hostname':'default file system port'/</value>
    </property>
</configuration>

See also configuration page for advanced configurations of Hama.

Advanced Properties

Launching Hama on YARN

Launch Hama application which is serialize printing example:

$HAMA_HOME/bin/hama jar hama-yarn-0.7.0.jar org.apache.hama.bsp.YarnSerializePrinting

You should see "Hello BSP" Messages which each container spawned in HDFS where you defined output path in your ternimal. If your application is success, you'll be able to got the following message.

INFO bsp.YARNBSPJobClient: Application has completed successfully. Breaking monitoring loop
Hello BSP from 1 of 4: cluster-0:16004
Hello BSP from 2 of 4: cluster-1:16006
Hello BSP from 3 of 4: cluster-0:16008
Hello BSP from 4 of 4: cluster-1:16010
Job Finished in 14.838 seconds

How to write a Hama-YARN job

BSP job

The BSPModel hasn't changed, but the way to submit a job has.

Basically you just need the following code to submit a Hama-YARN job.

    HamaConfiguration conf = new HamaConfiguration();
    YARNBSPJob job = new YARNBSPJob(conf);

    job.setBspClass(HelloBSP.class);
    job.setJarByClass(HelloBSP.class);
    job.setJobName("Serialize Printing");
    job.setMemoryUsedPerTaskInMb(50);
    job.setNumBspTask(2);
    job.waitForCompletion(false);

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job.setMemoryUsedPerTaskInMb(50);

How to configure a job

There are some configuration values that the job needs to have in order to submit sucessfully to YARN infrastructure.

The importantest configurations are the yarn.resourcemanager.address and fs.default.name. This should point to the address (hostname+port) where your ResourceManager and HDFS Namonode runs, for example localhost:8040, hdfs://localhost:9000.

Another important configuration value is the amount of memory used by the BSPApplicationMaster. You can configure a base amount of memory for the application master with this configuration key

hama.appmaster.memory.mb

By default, this is set to 100mb.

The total amount of memory used by the ApplicationMaster is calculated as follows

int memoryInMb = 3 * this.getNumBspTask() + conf.getInt("hama.appmaster.memory.mb", 100)

Graph job

Hama Graph jobs also isn't changed but you should change a little code from GraphJob to YARNGraphJob to run Hama graph job. Let's show the following link, PageRank on YARN.

PageRank on YARN example

Compared to PageRank in existing graph example, this code only is changed from GraphJob to YARNGraphJob. How to launch graph job on YARN is same as existing graph jobThis is because the application master spawns 1-3 threads per launched task that each should take 1mb, plus a minimum of base memory usage of 100. If you face memory issues, you can set this to a higher value.

How to submit a job

General

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to submit a Hama job. You can just change the BSPJob to YARNBSPJob.

Hama-YARN example

TODO this must be revised once the example has moved the jar.

bin/hama jar hama-yarn-0.7.0-SNAPSHOT.jar org.apache.hama.bsp.YarnSerializePrinting

Once running, you should see in the spawned application master log that it is launching containers. When the containers launched, you can see in the logs that there is a little "Hello World" from the other tasksIf you want to submit graph job of Hama, only change BSPJob object to YARNGraphJob.