Hadoop distributions (Cloudera, Hortonworks) - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Key difference between Cloudera and Hortonworks distributions

Which of the following best describes a main difference between Cloudera and Hortonworks Hadoop distributions?

A Hortonworks supports only MapReduce, Cloudera supports only Spark.

B Cloudera includes proprietary management tools, while Hortonworks is fully open source.

C Cloudera is based on Apache Hadoop 1.x, Hortonworks on Hadoop 3.x.

D Hortonworks requires a paid license, Cloudera is free.

💡 Hint

Think about the licensing and management tools each distribution offers.

Cloudera offers proprietary management and monitoring tools, while Hortonworks focuses on fully open source components.

❓ data_output

intermediate

Output of Hadoop version command in Cloudera vs Hortonworks

What output would you expect when running hadoop version on a Cloudera distribution compared to Hortonworks?

Hadoop

hadoop version

A Both show identical Apache Hadoop version numbers without any tags.

B Neither distribution supports the 'hadoop version' command.

C Cloudera shows a version with 'CDH' tag; Hortonworks shows 'HDP' tag.

D Cloudera shows 'HDP' tag; Hortonworks shows 'CDH' tag.

💡 Hint

Look for distribution-specific version identifiers.

Cloudera versions include 'CDH' (Cloudera Distribution Hadoop) in the version output, Hortonworks uses 'HDP' (Hortonworks Data Platform).

🔧 Debug

advanced

Identify the cause of a service failure in Hortonworks

You see the following error in Hortonworks Data Platform logs: Service failed to start due to missing dependency: Ambari Metrics. What is the most likely cause?

A Cloudera Manager is conflicting with Ambari Metrics.

B HDFS service is down, causing Ambari Metrics to fail.

C YARN resource manager is overloaded.

D Ambari Metrics service is not installed or not running.

💡 Hint

Think about what the error message says about dependencies.

Ambari Metrics is a required service in Hortonworks for monitoring. If it is missing or stopped, dependent services fail to start.

🚀 Application

advanced

Choosing a Hadoop distribution for a company with strict open source policy

A company requires a Hadoop distribution that is 100% open source with no proprietary components. Which distribution should they choose?

A Hortonworks, because it is fully open source without proprietary additions.

B Neither, both have proprietary components.

C Cloudera, because it offers proprietary tools for better management.

D Use Apache Hadoop directly, not a distribution.

💡 Hint

Consider the licensing and source code openness of each distribution.

Hortonworks is known for being fully open source, while Cloudera includes proprietary management tools.

🧠 Conceptual

expert

Impact of Cloudera and Hortonworks merger on Hadoop ecosystem

After the merger of Cloudera and Hortonworks, what is the expected impact on the Hadoop ecosystem?

A Unified platform combining proprietary and open source tools, simplifying management.

B Removal of all open source components in favor of proprietary software.

C Splitting into two separate competing distributions.

D Complete abandonment of Hadoop in favor of cloud-only solutions.

💡 Hint

Think about the goal of merging two major distributions.

The merger aimed to combine strengths of both distributions, offering a unified platform with both proprietary and open source tools.

Practice

1. What is the main purpose of Hadoop distributions like Cloudera and Hortonworks?

easy

A. To provide only storage without any processing capabilities

B. To replace Hadoop with a completely different big data system

C. To bundle Hadoop with extra tools and support for easier big data management

D. To limit Hadoop usage to small datasets only

Solution

1. Step 1: Understand what Hadoop distributions include

   Hadoop distributions package Hadoop core with additional tools and management features.

2. Step 2: Identify the purpose of these added tools

   These tools help users manage big data projects more easily and reliably.

3. Final Answer:

   To bundle Hadoop with extra tools and support for easier big data management -> Option C

4. Quick Check:

   Distributions = Hadoop + tools + support [OK]

Hint: Distributions add tools and support to Hadoop [OK]

Common Mistakes:

• Thinking distributions replace Hadoop
• Believing distributions only provide storage
• Assuming distributions limit data size

2. Which of the following is the correct way to describe Cloudera in the context of Hadoop?

easy

A. A Hadoop distribution that includes management and security tools

B. A programming language used to write Hadoop jobs

C. A cloud service unrelated to Hadoop

D. A database system that replaces Hadoop

Solution

1. Step 1: Identify Cloudera's role

   Cloudera is known as a Hadoop distribution with extra management and security features.

2. Step 2: Eliminate incorrect options

   It is not a programming language, cloud service unrelated to Hadoop, or a database replacing Hadoop.

3. Final Answer:

   A Hadoop distribution that includes management and security tools -> Option A

4. Quick Check:

   Cloudera = Hadoop distribution + tools [OK]

Hint: Cloudera bundles Hadoop with management tools [OK]

Common Mistakes:

• Confusing Cloudera with a programming language
• Thinking Cloudera is unrelated to Hadoop
• Assuming Cloudera replaces Hadoop

3. Given the following code snippet in a Hadoop environment using Hortonworks distribution, what will be the output?

from hdfs import InsecureClient
client = InsecureClient('http://localhost:50070')
files = client.list('/user/hadoop')
print(len(files))

medium

A. A syntax error due to missing import

B. The number of files in the /user/hadoop directory

C. An empty list printed

D. A runtime error because the client URL is incorrect

Solution

1. Step 1: Understand the code functionality

   The code connects to HDFS via Hortonworks client and lists files in /user/hadoop directory.

2. Step 2: Analyze the output of print(len(files))

   It prints the count of files found in that directory, which is the length of the list returned.

3. Final Answer:

   The number of files in the /user/hadoop directory -> Option B

4. Quick Check:

   len(files) = file count [OK]

Hint: list() returns files; len() counts them [OK]

Common Mistakes:

• Confusing list() output with file contents
• Expecting syntax error without cause
• Assuming client URL is always wrong

4. Identify the error in this Hortonworks Hadoop configuration snippet:

hdfs-site.xml content:
<configuration>
  <property>
    <name>dfs.replication</name>
    <value>one</value>
  </property>
</configuration>

medium

A. The replication value should be a number, not the word 'one'

B. The property name dfs.replication is incorrect

C. The XML tags are not closed properly

D. The configuration file should be named core-site.xml

Solution

1. Step 1: Check the dfs.replication value type

   The dfs.replication property expects a numeric value indicating replication factor.

2. Step 2: Identify the error in the value

   The value 'one' is a string and invalid; it should be a number like 1.

3. Final Answer:

   The replication value should be a number, not the word 'one' -> Option A

4. Quick Check:

   dfs.replication = numeric value [OK]

Hint: Replication factor must be numeric [OK]

Common Mistakes:

• Using words instead of numbers for replication
• Confusing property names
• Misnaming configuration files

5. You want to migrate a big data project from Hortonworks to Cloudera. Which of the following steps is MOST important to ensure a smooth transition?

hard

A. Rewrite all Hadoop MapReduce jobs in a new programming language

B. Ignore configuration differences since both are Hadoop

C. Delete all data before migration to avoid conflicts

D. Verify compatibility of data formats and replication settings between distributions

Solution

1. Step 1: Understand migration challenges

   Different Hadoop distributions may have subtle differences in data formats and replication configurations.

2. Step 2: Identify key step for smooth migration

   Verifying compatibility of these settings prevents data loss or errors during migration.

3. Final Answer:

   Verify compatibility of data formats and replication settings between distributions -> Option D

4. Quick Check:

   Check compatibility before migration [OK]

Hint: Check data and config compatibility before migrating [OK]

Common Mistakes:

• Thinking rewriting code is always needed
• Deleting data unnecessarily
• Ignoring config differences