Hadoop distributions (Cloudera, Hortonworks) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Hadoop distribution?

A Hadoop distribution is a packaged version of the Hadoop software that includes additional tools, management features, and support to make it easier to install, use, and maintain Hadoop clusters.

beginner

Name two popular Hadoop distributions.

Two popular Hadoop distributions are Cloudera and Hortonworks.

intermediate

What was a key difference between Cloudera and Hortonworks before their merger?

Cloudera focused on enterprise features and proprietary tools, while Hortonworks was known for its commitment to open-source and community-driven development.

intermediate

What is the significance of the Cloudera-Hortonworks merger?

The merger combined the strengths of both companies to create a unified Hadoop platform with better support, tools, and innovation for big data management.

beginner

List one common tool included in both Cloudera and Hortonworks distributions.

Apache Hive is a common tool included in both distributions, used for querying and managing large datasets stored in Hadoop.

What does a Hadoop distribution typically include?

A Operating system updates

B Only the core Hadoop code

C Additional tools and management features

D A web browser

Hadoop distributions package Hadoop with extra tools and management features to simplify use.

Which company was known for focusing on open-source Hadoop development before merging?

A Hortonworks

B Cloudera

C Microsoft

D Google

Hortonworks was known for its open-source and community-driven approach.

What is Apache Hive used for in Hadoop distributions?

A Network security

B Data querying and management

C Operating system installation

D Web development

Apache Hive allows users to query and manage large datasets in Hadoop.

What was a main benefit of the Cloudera-Hortonworks merger?

A Unified Hadoop platform with better tools

B Stopped Hadoop development

C Created a new programming language

D Focused only on cloud services

The merger combined strengths to improve Hadoop tools and support.

Which of these is NOT typically part of a Hadoop distribution?

A Security features

B Data processing frameworks

C Management tools

D Video editing software

Video editing software is unrelated to Hadoop distributions.

Explain what a Hadoop distribution is and why companies like Cloudera and Hortonworks created their own versions.

Think about how software packages help users manage complex systems.

Describe the impact of the Cloudera and Hortonworks merger on the Hadoop ecosystem.

Consider how merging companies can improve technology offerings.

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