Spring Spark Cassandra - Whitelabel Error Page - apache-spark

Question

I am trying to use spark and cassandra through Spring in netbeans and I get an error:
type=Internal Server Error, status=500
Failed to open native connection to Cassandra at {127.0.0.1}:9042.
Spark and Cassandra were functioning just fine before I try to integrate Spring. There are already data in my Cassandra database which I take through spark and process them. Basically, I want to print the results(a matrix) in a /welcome page through a RestController.
Here is my really simple File Structure:
image
Here is my pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.mycompany</groupId>
<artifactId>my-app</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<debug>true</debug>
</configuration>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>2.0.0.RELEASE</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<!--Spring dependencies-->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.0</version>
</dependency>
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.2</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>2.0.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>5.0.4.RELEASE</version>
</dependency>
<!--Spark dependencies-->
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-core_2.11</artifactId>
<version>2.2.1</version>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-sql_2.11</artifactId>
<version>2.2.1</version>
</dependency>
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-mllib_2.11</artifactId>
<version>2.2.1</version>
</dependency>
<!--Cassandra dependencies-->
<!--Spark cassandra connector dependencies-->
<dependency>
<groupId>com.datastax.spark</groupId>
<artifactId>spark-cassandra-connector_2.11</artifactId>
<version>2.0.7</version>
</dependency>
</dependencies>
The spark context and session initialization:
#Configuration
public class Sparkstart {
#Bean
public SparkSession sparksession() {
SparkSession sp = SparkSession
.builder()
.master("local[*]")
.appName("preprocessing")
.config("spark.cassandra.connection.host","127.0.0.1")
.getOrCreate();
return sp;
}
#Bean
public JavaSparkContext sc(){
JavaSparkContext sc = new JavaSparkContext(sparksession().sparkContext());
return sc;
}
}
The class where I take the data from Cassandra database:
#Component
public class Aftersparkstart {
#Autowired
private SparkSession sp;
#Autowired
private JavaSparkContext sc;
#Autowired
private Pearsonclass prs;
public Matrix start(){
List<String> desclist = new ArrayList<>();
desclist.add(some data);
desclist.add(some data);
Dataset<Row> peakset = sp.read().format("org.apache.spark.sql.cassandra")
.options(new HashMap<String, String>() {
{
put("keyspace", "mdb");
put("table", "filepeaks");
}
})
.load().select(col("directoryname"), col("description"), col("intensity")).filter(col("description").isin(desclist.toArray()));
Dataset<Row> finalpeaks = peakset.groupBy(peakset.col("description"), peakset.col("directoryname")).avg("intensity").orderBy(asc("directoryname"), asc("description"));
Matrix r=prs.pearsonmethod(finalpeaks,dirlist,desclist);
return r;
}
}
And the class where the processing by spark takes place:
#Component
public class Pearsonclass{
public Matrix pearsonmethod(Dataset<Row> peaks, List<String> dirlist, List<String> desclist) {
"...stuff..."
return r2;
}
}
And finally the RestController:
#RestController
public class Firstcontroller {
#Autowired
private Aftersparkstart str;
#RequestMapping("/welcome")
public Matrix welcome(){
//return wlc.retrievemsg();
return str.start();
}
}
I am pretty sure I am missing something in the dependencies but I don't know what!

Answer 1

Got it! I just upgraded my Cassandra version from 3.11.0 to 3.11.2. The problem was JDK incompatibility with Cassandra. I have 1.8.0_162-8u162 with which the previous Cassandra version didn't get along..!