run_spark_job_inside_cluster.md

How to Run Spark Job inside the Cluster

Spark program that runs inside a SnappyData cluster is implemented as a SnappyData job.

Implementing a Job: A SnappyData job is a class or object that implements SnappySQLJob or SnappyStreamingJob (for streaming applications) trait. In the runSnappyJob method of the job, you implement the logic for your Spark program using SnappySession object instance passed to it. You can perform all operations such as create a table, load data, execute queries using the SnappySession.
Any of the Spark APIs can be invoked by a SnappyJob.

class CreatePartitionedRowTable extends SnappySQLJob {
  /** SnappyData uses this as an entry point to execute Snappy jobs. **/
  def runSnappyJob(sc: SnappySession, jobConfig: Config): Any

  /**
  SnappyData calls this function to validate the job input and reject invalid job requests.
  You can implement custom validations here, for example, validating the configuration parameters
  **/
  def isValidJob(sc: SnappySession, config: Config): SnappyJobValidation
}

Dependencies: To compile your job, use the Maven/Gradle/SBT dependencies for the latest released version of SnappyData.

=== "Maven"

```xml
 <!-- https://mvnrepository.com/artifact/io.snappydata/snappydata-cluster_2.11 -->
  <repositories>
    <repository>
      <id>cloudera-repo</id>
      <name>cloudera repo</name>
      <url>https://repository.cloudera.com/artifactory/cloudera-repos</url>
    </repository>
    ...
  </repositories>

  <dependencies>
    <dependency>
      <groupId>io.snappydata</groupId>
      <artifactId>snappydata-cluster_2.11</artifactId>
      <version>1.3.1</version>
    </dependency>
    ...
  </dependencies>
```

=== "Gradle"

```groovy
// https://mvnrepository.com/artifact/io.snappydata/snappydata-cluster_2.11
repositories {
  mavenCentral()
  maven { url 'https://repository.cloudera.com/artifactory/cloudera-repos' }
  ...
}

dependencies {
  implementation 'io.snappydata:snappydata-cluster_2.11:1.3.1'
  ...
}
```

=== "SBT"

```scala
// https://mvnrepository.com/artifact/io.snappydata/snappydata-cluster_2.11
resolvers += "Cloudera Repo" at "https://repository.cloudera.com/artifactory/cloudera-repos"

libraryDependencies += "io.snappydata" % "snappydata-cluster_2.11" % "1.3.1"
```

!!! Note

If your project fails while resolving the above dependency (ie. it fails to download javax.ws.rs#javax.ws.rs-api;2.1), it may be due an issue with its pom file. </br> As a workaround, add the below code to the `build.sbt`:

```scala
val workaround = {
  sys.props += "packaging.type" -> "jar"
  ()
}
```

For more details, refer [https://github.com/sbt/sbt/issues/3618](https://github.com/sbt/sbt/issues/3618).

Running the Job: Once you create a jar file for SnappyData job, use the ./bin/snappy-job.sh to submit the job in the SnappyData cluster, and then run the job. This is similar to spark-submit for any Spark application.

For example, to run the job implemented in CreatePartitionedRowTable.scala you can use the following command. The command submits the job and runs it as:

 # first change the directory to the SnappyData product directory
 $ cd $SNAPPY_HOME
 $ ./bin/snappy-job.sh submit
    --app-name CreatePartitionedRowTable
    --class org.apache.spark.examples.snappydata.CreatePartitionedRowTable
    --app-jar examples/jars/quickstart.jar
    --lead localhost:8090

In the above command, quickstart.jar contains the program and is bundled in the product distribution and the --lead option specifies the host name of the lead node along with the port on which it accepts jobs (default 8090).

Output: It returns output similar to:

{
  "status": "STARTED",
  "result": {
    "jobId": "321e5136-4a18-4c4f-b8ab-f3c8f04f0b48",
    "context": "snappyContext1452598154529305363"
  }
}

Check Status: You can check the status of the job using the Job ID listed above:

./bin/snappy-job.sh status --lead localhost:8090 --job-id 321e5136-4a18-4c4f-b8ab-f3c8f04f0b48

Refer to the Building SnappyData applications using Spark API section of the documentation for more details.