Cloudera CCA175 - CCA Spark and Hadoop Developer Exam

Solution :

Step 1 : Import Single table

sqoop import --connect jdbc:mysql://quickstart:3306/retail_db --username=retail dba -password=cloudera -table=orders --target-dir=p91_orders

Note : Please check you dont have space between before or after '=' sign. Sqoop uses the MapReduce framework to copy data from RDBMS to hdfs

Step 2 : Read the data from one of the partition, created using above command, hadoop fs -cat p91_orders/part-m-00000

Step 3: countByKey #Number of orders by status allOrders = sc.textFile("p91_orders")

#Generate key and value pairs (key is order status and vale as an empty string keyValue = aIIOrders.map(lambda line: (line.split(",")[3], ""))

#Using countByKey, aggregate data based on status as a key output=keyValue.countByKey()Jtems()

for line in output: print(line)

Step 4 : groupByKey

#Generate key and value pairs (key is order status and vale as an one

keyValue = allOrders.map(lambda line: (line.split)",")[3], 1))

#Using countByKey, aggregate data based on status as a key output= keyValue.groupByKey().map(lambda kv: (kv[0], sum(kv[1]}}}

tor line in output.collect(): print(line}

Step 5 : reduceByKey

#Generate key and value pairs (key is order status and vale as an one

keyValue = allOrders.map(lambda line: (line.split(","}[3], 1))

#Using countByKey, aggregate data based on status as a key output= keyValue.reduceByKey(lambda a, b: a + b)

tor line in output.collect(): print(line}

Step 6: aggregateByKey

#Generate key and value pairs (key is order status and vale as an one keyValue = allOrders.map(lambda line: (line.split(",")[3], line}}

output=keyValue.aggregateByKey(0, lambda a, b: a+1, lambda a, b: a+b}

for line in output.collect(): print(line}

Step 7 : combineByKey

#Generate key and value pairs (key is order status and vale as an one

keyValue = allOrders.map(lambda line: (line.split(",")[3], line))

output=keyValue.combineByKey(lambda value: 1, lambda ace, value: acc+1, lambda ace, value: acc+value)

tor line in output.collect(): print(line)

#Watch Spark Professional Training provided by www.ABCTECH.com to understand more on each above functions. (These are very important functions for real exam)

Solution :

b.foidByKey("")(_ + J.collect

foldByKey [Pair]

Very similar to fold, but performs the folding separately for each key of the RDD. This function is only available if the RDD consists of two-component tuples

Listing Variants

def foldByKey(zeroValue: V)(func: (V, V) => V): RDD[(K, V}]

def foldByKey(zeroValue: V, numPartitions: lnt)(func: (V, V) => V): RDD[(K, V)]

def foldByKey(zeroValue: V, partitioner: Partitioner)(func: (V, V) => V): RDD[(K, V}]

Solution :

Step 1 : Create directory

hdfs dfs -mkdir hdfs_commands

Step 2 : Create a file in hdfs named data.txt in hdfs_commands. hdfs dfs -touchz hdfs_commands/data.txt

Step 3 : Now copy this data.txt file on local filesystem, however while copying file please make sure file properties are not changed e.g. file permissions.

hdfs dfs -copyToLocal -p hdfs_commands/data.txt/home/cloudera/Desktop/HadoopExam

Step 4 : Now create a file in local directory named data_local.txt and move this file to hdfs in hdfs_commands directory.

touch data_local.txt

hdfs dfs -moveFromLocal /home/cloudera/Desktop/HadoopExam/dataJocal.txt hdfs_commands/

Step 5 : Create a file data_hdfs.txt in hdfs_commands directory and copy it to local file system.

hdfs dfs -touchz hdfscommands/data hdfs.txt

hdfs dfs -getfrdfs_commands/data_hdfs.txt /home/cloudera/Desktop/HadoopExam/

Step 6 : Create a file in local filesystem named filel .txt and put it to hdfs

touch filel.txt

hdfs dfs -put/home/cloudera/Desktop/HadoopExam/file1.txt hdfs_commands/

Solution :

A case (key, groupValues)

B (key._1, key._2, value._1, value._2)

Solution

XXX: -master local[8]

Notes : The master URL passed to Spark can be in one of the following formats:

Master URL Meaning

local Run Spark locally with one worker thread (i.e. no parallelism at all}.

local[K] Run Spark locally with K worker threads (ideally, set this to the number of cores on your machine).

local[*] Run Spark locally with as many worker threads as logical cores on your machine.

spark://HOST:PORT Connect to the given Spark standalone cluster master. The port must be whichever one your master is configured to use, which is 7077 by default.

mesos://HOST:PORT Connect to the given Mesos cluster. The port must be whichever one your is configured to use, which is 5050 by default. Or, for a Mesos cluster using ZooKeeper, use mesos://zk://.... To submit with --deploy-mode cluster, the HOST:PORT should be configured to connect to the MesosClusterDispatcher.

yarn Connect to a YARN cluster in client or cluster mode depending on the value of -deploy-mode. The cluster location will be found based on the HADOOP CONF DIR or YARN CONF DIR variable.

Solution :

Step 1 : Create 2 files first using Hue in hdfs.

Step 2 : Load all file as an RDD

val technology = sc.textFile(Msparkl2/technology.txt").map(e => e.splitf',"))

val salary = sc.textFile("spark12/salary.txt").map(e => e.split("."))

Step 3 : Now create Key.value pair of data and join them.

val joined = technology.map(e=>((e(0),e(1)),e(2))).join(salary.map(e=>((e(0),e(1)),e(2))))

Step 4 : Save the results in a text file as below.

joined.repartition(1).saveAsTextFile("spark12/multiColumn Joined.txt")

Solution

XXX: Mspark.executoi\extraJavaOptions=-XX:+PrintGCDetails -XX:+PrintGCTimeStamps"

Notes: ./bin/spark-submit \

--class

--master \

--deploy-mode \

-conf = \

# other options

\

[application-arguments]

Here, conf is used to pass the Spark related contigs which are required for the application to run like any specific property(executor memory) or if you want to override the default property which is set in Spark-default.conf.

Solution :

Step 1 : Login to musql db

mysql --user=retail_dba -password=cloudera

show databases; use retail_db; show tables;

step 2 : Create a table as given in problem statement.

CREATE table departments_export (departmentjd int(11), department_name varchar(45), created_date T1MESTAMP DEFAULT NOW());

show tables;

Step 3 : Export data from /user/cloudera/departmentsnew to new table departments_export

sqoop export -connect jdbc:mysql://quickstart:3306/retail_db \

-username retaildba \

--password cloudera \

--table departments_export \

-export-dir /user/cloudera/departments_new \

-batch

Step 4 : Now check the export is correctly done or not. mysql -user*retail_dba -password=cloudera

show databases;

use retail _db;

show tables;

select' from departments_export;

Solution :

A. NullWritable

B. BytesWritable

Solution

XXX: -master yarn

YYY : -executor-memory 20G

ZZZ: -num-executors 50