I have an easy task: I want to read HBase data in a Kerberos secured cluster.
So far I tried 2 approaches:
sc.newAPIHadoopRDD(): here I don't know how to handle the kerberos authentication
create a HBase connection from the HBase API: Here I don't really know how to convert the result into RDDs
Furthermore there seem to be some HBase-Spark connectors. But somehow I didn't really manage to find them as Maven artifact and/or they require a fixed structure of the result (but I just need to have the HBase Result object since the columns in my data are not fixed).
Do you have any example or tutorials or ....?
I appreciate any help and hints.
Thanks in advance!
I assume that you are using spark + scala +Hbase
import org.apache.spark._
import org.apache.spark.rdd.NewHadoopRDD
import org.apache.hadoop.hbase.{HBaseConfiguration, HTableDescriptor}
import org.apache.hadoop.hbase.client.HBaseAdmin
import org.apache.hadoop.hbase.mapreduce.TableInputFormat
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HColumnDescriptor
import org.apache.hadoop.hbase.util.Bytes
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.HTable;
object SparkWithMyTable {
def main(args: Array[String]) {
//Initiate spark context with spark master URL. You can modify the URL per your environment.
val sc = new SparkContext("spark://ip:port", "MyTableTest")
val tableName = "myTable"
val conf = HBaseConfiguration.create()
conf.set("hbase.zookeeper.quorum", "list of cluster ip's")
conf.set("hbase.zookeeper"+ ".property.clientPort","2181");
conf.set("hbase.master", "masterIP:60000");
conf.set("hadoop.security.authentication", "kerberos");
conf.set("hbase.security.authentication", "kerberos");
UserGroupInformation.setConfiguration(conf);
UserGroupInformation.loginUserFromKeytab("user#---", keyTabPath);
// Add local HBase conf
// conf.addResource(new Path("file://hbase/hbase-0.94.17/conf/hbase-site.xml"))
conf.set(TableInputFormat.INPUT_TABLE, tableName)
// create my table with column family
val admin = new HBaseAdmin(conf)
if(!admin.isTableAvailable(tableName)) {
print("Creating MyTable")
val tableDesc = new HTableDescriptor(tableName)
tableDesc.addFamily(new HColumnDescriptor("cf1".getBytes()));
admin.createTable(tableDesc)
}else{
print("Table already exists!!")
val columnDesc = new HColumnDescriptor("cf1");
admin.disableTable(Bytes.toBytes(tableName));
admin.addColumn(tableName, columnDesc);
admin.enableTable(Bytes.toBytes(tableName));
}
//first put data into table
val myTable = new HTable(conf, tableName);
for (i <- 0 to 5) {
var p = new Put();
p = new Put(new String("row" + i).getBytes());
p.add("cf1".getBytes(), "column-1".getBytes(), new String(
"value " + i).getBytes());
myTable.put(p);
}
myTable.flushCommits();
//how to create rdd
val hBaseRDD = sc.newAPIHadoopRDD(conf, classOf[TableInputFormat],
classOf[org.apache.hadoop.hbase.io.ImmutableBytesWritable],
classOf[org.apache.hadoop.hbase.client.Result])
//get the row count
val count = hBaseRDD.count()
print("HBase RDD count:"+count)
System.exit(0)
}
}
Maven Artifact
<dependency>
<groupId>it.nerdammer.bigdata</groupId>
<artifactId>spark-hbase-connector_2.10</artifactId>
<version>1.0.3</version> // Version can be changed as per your Spark version, I am using Spark 1.6.x
</dependency>
Can also have a look at
Spark play with HBase's Result object: handling HBase KeyValue and ByteArray in Scala with Spark -- Real World Examples
scan-that-works-on-kerberos
HBaseScanRDDExample.scala
Related
I am trying to integrate Spark and Neo4j. I am new to Neo4j. I have the following short Spark app
import com.typesafe.config._
import org.apache.spark.sql.SparkSession
import org.neo4j.spark._
object Neo4jStorer {
var conf :Config = null
def main(args: Array[String]): Unit = {
val spark = getSparkSession()
val sc = spark.sparkContext
val g = Neo4jGraph.loadGraph(sc, label1="a", relTypes=Seq("rel"), label2 = "b")
val vCount = g.toString
println("Count= " + vCount)
}
def getSparkSession(): SparkSession = {
SparkSession
.builder
.appName("SparkNeo4j")
.config("spark.neo4j.bolt.url", "neo4j://127.0.0.1:7687")
.config("spark.neo4j.bolt.user", "neo4j")
.config("spark.neo4j.bolt.password", "FakePassword")
.getOrCreate()
}
}
I used https://neo4j.com/blog/neo4j-3-0-apache-spark-connector/ as an example for this code as I am using Spark 3.0. When I run this I get the following
20/10/17 14:36:36 ERROR LoadBalancer: Failed to update routing table for database 'FakePassword'. Current routing table: Ttl 1602963396190, currentTime 1602963396527, routers AddressSet=[], writers AddressSet=[], readers AddressSet=[], database 'FakePassword'.
org.neo4j.driver.exceptions.FatalDiscoveryException: Unable to get a routing table for database 'FakePassword' because this database does not exist
If I change the password I get an authentication error and I see that again the incorrect password is shown as being a database. I created a database with the name FakePassword and I still got the same error. Why is this happening and how can I fix it?
Also when I tried to get g.vertices.count as is shown in the example I am following I get a compilation error.
With this code I am able to get data from a DataFrame into Neo4j, which is what I really wanted to do. This does not seem to be the ideal solution as it uses foreach. I am open to improvements.
import com.typesafe.config._
import org.apache.spark.sql.SparkSession
import org.neo4j.driver.{AuthTokens, GraphDatabase, Session}
import org.neo4j.spark._
object StackoverflowAnswer {
def main(args: Array[String]): Unit = {
val spark = getSparkSession()
val sc = spark.sparkContext
import spark.implicits._
val df = sc.parallelize(List(1, 2, 3)).toDF
df.foreach(
row => {
val query = "CREATE (n:NumLable {num: " + row.get(0).toString +"})"
Neo4jSess.session.run(query)
()
}
)
}
def getSparkSession(): SparkSession = {
SparkSession
.builder
.appName("SparkNeo4j")
.getOrCreate()
}
}
object Neo4jSess {
/**
* Store a Neo4j session in a object so that it can be used by Spark
*/
var conf :Config = null
this.conf = ConfigFactory.load().getConfig("DeltaStorer")
val neo4jUrl: String = "bolt://127.0.0.1:7687"
val neo4jUser: String = "neo4j"
val neo4jPassword: String = "FakePassword"
val driver = GraphDatabase.driver(neo4jUrl, AuthTokens.basic(neo4jUser, neo4jPassword))
val session: Session = driver.session()
}
Please try to update spark-defaults.conf:
spark.jars.packages neo4j-contrib:neo4j-spark-connector:2.4.5-M2
spark.neo4j.url bolt://XX.XXX.X.XXX:7687
spark.neo4j.user neo4j
spark.neo4j.password test
I want to migrate my old cassandra cluster data to a new cluster and thinking to write some spark jobs to do that. Is there any way to interact with multiple cassandra cluster from the same SparkContext. So that i can read the data from one cluster and write to another cluster using saveToCassandra function inside the same sparkJob.
val products = sc.cassandraTable("first_cluster","products").cache()
products.saveToCassandra("diff_cluster","products2")
Can we save the data into a different cluster ?
Example from spark-cassandra-connector
import com.datastax.spark.connector._
import com.datastax.spark.connector.cql._
import org.apache.spark.SparkContext
def twoClusterExample ( sc: SparkContext) = {
val connectorToClusterOne = CassandraConnector(sc.getConf.set("spark.cassandra.connection.host", "127.0.0.1"))
val connectorToClusterTwo = CassandraConnector(sc.getConf.set("spark.cassandra.connection.host", "127.0.0.2"))
val rddFromClusterOne = {
// Sets connectorToClusterOne as default connection for everything in this code block
implicit val c = connectorToClusterOne
sc.cassandraTable("ks","tab")
}
{
//Sets connectorToClusterTwo as the default connection for everything in this code block
implicit val c = connectorToClusterTwo
rddFromClusterOne.saveToCassandra("ks","tab")
}
}
I am trying to use preparestatement with JDBC. It results ResultSet object. I want to convert it into spark dataframe.
object JDBCRead {
val tableName:String = "TABLENAME"
val url :String = "jdbc:teradata://TERADATA_URL/user=USERNAME,password=PWD,charset=UTF8,TYPE=FASTEXPORT,SESSIONS=10"
val selectTable:String = "SELECT * FROM " + tableName +" sample 10";
val con : Connection = DriverManager.getConnection(url);
val pstmt2: PreparedStatement = con.prepareStatement(selectTable)
import java.sql.ResultSet
val rs: ResultSet = pstmt2.executeQuery
val rsmd: ResultSetMetaData = rs.getMetaData
while(rs.next()!=null)
{
val k: Boolean = rs.next()
for(i<-1 to rsmd.getColumnCount) {
print(" " + rs.getObject(i))
}
println()
}
}
I want to call above code from Spark Dataframe so that I can load the data into dataframe and get the results faster distributedly.
I must use PreparedStatement. I can not use spark.jdbc.load since FASTEXPORT of Teradata does not work with jdbc load. It has to be used with PreparedStatement
How to achieve this? How can I user preparestatement along with SELECT statement to load into Spark Dataframe.
-
AFAIK there are 2 options available for this kind of requirements
1. DataFrame 2. JdbcRDD
I'd offer JdbcRDD (since you are so specific to preparedstatement)
Which used prepareStatement internally in compute method. Therefore, you don't need to create connection and maintain it explicitly(error prone).
Later you can convert result in to dataframe
For speed you can configure other parameters.
Example code usage of JdbcRDD is below..
import org.apache.log4j.{Level, Logger}
import org.apache.spark.SparkContext
import org.apache.spark.SparkContext.__
import org.apache.spark.SparkConf
import org.apache.spark.rdd.JdbcRDD
import java.sql.{connection, DriverManager,ResultSet}
object jdbcRddExample {
def main(args: Array[String]) {
// Connection String
VAL URL = "jdbc:teradata://SERVER/demo"
val username = "demo"
val password = "Spark"
Class.forName("com.teradata.jdbc.Driver").newInstance
// Creating & Configuring Spark Context
val conf = new SparkConf().setAppName("App1").setMaster("local[2]").set("spark.executor.memory",1)
val sc = new SparkContext(conf)
println("Start...")
// Fetching data from Database
val myRDD = new JdbcRDD(sc,() => DriverManager.getConnection(url,username,password),
"select first_name, last_name, gender from person limit ?,?",
3,5,1,r => r.getString("last_name") + "," +r.getString("first_name"))
// Displaying the content
myRDD.foreach(println)
// Saving the content inside Text File
myRDD.saveAsTextFile("c://jdbcrdd")
println("End...")
}
}
When following the zeppelin tutorial for streaming tweets and querying them using SparkSQL, am running into error where the 'tweets' temp table is not found. The exact code being used and links referred as as follows
Ref: https://zeppelin.apache.org/docs/0.6.2/quickstart/tutorial.html
import scala.collection.mutable.HashMap
import org.apache.spark.streaming._
import org.apache.spark.streaming.twitter._
import org.apache.spark.storage.StorageLevel
import scala.io.Source
import scala.collection.mutable.HashMap
import java.io.File
import org.apache.log4j.Logger
import org.apache.log4j.Level
import sys.process.stringSeqToProcess
/** Configures the Oauth Credentials for accessing Twitter */
def configureTwitterCredentials(apiKey: String, apiSecret: String, accessToken: String, accessTokenSecret: String) {
val configs = new HashMap[String, String] ++= Seq(
"apiKey" -> apiKey, "apiSecret" -> apiSecret, "accessToken" -> accessToken, "accessTokenSecret" -> accessTokenSecret)
println("Configuring Twitter OAuth")
configs.foreach{ case(key, value) =>
if (value.trim.isEmpty) {
throw new Exception("Error setting authentication - value for " + key + " not set")
}
val fullKey = "twitter4j.oauth." + key.replace("api", "consumer")
System.setProperty(fullKey, value.trim)
println("\tProperty " + fullKey + " set as [" + value.trim + "]")
}
println()
}
// Configure Twitter credentials
val apiKey = "xxx"
val apiSecret = "xxx"
val accessToken = "xx-xxx"
val accessTokenSecret = "xxx"
configureTwitterCredentials(apiKey, apiSecret, accessToken, accessTokenSecret)
import org.apache.spark.streaming._
import org.apache.spark.streaming.twitter._
#transient val ssc = new StreamingContext(sc, Seconds(2))
#transient val tweets = TwitterUtils.createStream(ssc, None)
#transient val twt = tweets.window(Seconds(60), Seconds(2))
val sqlContext= new org.apache.spark.sql.SQLContext(sc)
import sqlContext.implicits._
case class Tweet(createdAt:Long, text:String)
twt.map(status=>
Tweet(status.getCreatedAt().getTime()/1000, status.getText())).foreachRDD(rdd=>
// Below line works only in spark 1.3.0.
// For spark 1.1.x and spark 1.2.x,
// use rdd.registerTempTable("tweets") instead.
rdd.toDF().registerTempTable("tweets")
)
ssc.start()
In the next paragraph, i have the SQL select statement
%sql select createdAt, count(1) from tweets group by createdAt order by createdAt
Which throws the following exception
org.apache.spark.sql.AnalysisException: Table not found: tweets;
at org.apache.spark.sql.catalyst.analysis.package$AnalysisErrorAt.failAnalysis(package.scala:42)
at org.apache.spark.sql.catalyst.analysis.Analyzer$ResolveRelations$.getTable(Analyzer.scala:305)
Was able to get the above example running by making following edits. Am not sure, if this change was needed due to version upgrade of Spark (v1.6.3) or some other underlying architecture nuances i might be missing, but eitherways
REF: SparkSQL error Table Not Found
In the second para' instead of directly invoking as SQL syntax, try using the sqlContext as follows
val my_df = sqlContext.sql("SELECT * from sweets LIMIT 5")
my_df.collect().foreach(println)
I am running the program below on Spark 1.3.1. Spark Streaming is watching a directory in HDFS for new files and should process them as they come in. I have read that the best way to do this is to move the files from an existing HDFS location so that the operation is atomic.
I start my streaming job, I add a bunch of small files to a random HDFS directory, then I move these files from the original HDFS directory to the watched HDFS directory (all with simple shell commands). But my streaming job is not recognizing these as new files and therefore not processing them.
Currently I am using textFileStream but am open to using fileStream. However I am getting errors with this val lines = ssc.fileStream[LongWritable, Text, TextInputFormat]("hdfs:///name/spark-streaming/data/", (p: Path)=>true, false)
package com.com.spark.prototype
import java.io.FileInputStream
import org.apache.hadoop.fs.Path
import org.apache.hadoop.io.LongWritable
import org.apache.hadoop.mapred.TextInputFormat
import org.apache.spark._
import org.apache.spark.streaming._
import com.twitter.algebird.HyperLogLogMonoid
import org.apache.hadoop.io._
object HLLStreamingHDFSTest {
def functionToCreateContext(): StreamingContext = {
val conf = new SparkConf().set("spark.executor.extraClassPath", "/home/hadoop/spark/conf:/home/hadoop/conf:/home/hadoop/spark/classpath/emr/*:/home/hadoop/spark/classpath/emrfs/*:/home/hadoop/share/hadoop/common/lib/*:/home/hadoop/share/hadoop/common/lib/hadoop-lzo.jar")
val ssc = new StreamingContext(conf, Seconds(5))
ssc.checkpoint("/name/spark-streaming/checkpointing")
val lines = ssc.textFileStream("hdfs:///name/spark-streaming/data/")
val hll = new HyperLogLogMonoid(15)
var globalHll = hll.zero
val users = lines.map(_.toString().toCharArray.map(_.toByte))
val approxUsers = users.mapPartitions(ids => {
ids.map(id => hll(id))
}).reduce(_ + _)
approxUsers.foreachRDD(rdd => {
if (rdd.count() != 0) {
val partial = rdd.first()
globalHll += partial
println()
println()
println("Estimated distinct users this batch: %d".format(partial.estimatedSize.toInt))
println("Estimated distinct users this batch: %d".format(globalHll.estimatedSize.toInt))
println()
println("Approx distinct users this batch: %s".format(partial.approximateSize.toString))
println("Approx distinct users overall: %s".format(globalHll.approximateSize.toString))
}
})
ssc
}
def main(args: Array[String]): Unit = {
val context = StreamingContext.getOrCreate("hdfs:///name/spark-streaming/checkpointing", functionToCreateContext _)
context.start()
context.awaitTermination()
}
}