Monitoring with Ambari or Cloudera Manager in Hadoop - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the Ambari server service.

Hadoop

sudo systemctl [1] ambari-server

Drag options to blanks, or click blank then click option'

Astop

Bstatus

Cstart

Drestart

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'stop' instead of 'start'.

Using 'status' which only shows service state.

To start the Ambari server, use systemctl start ambari-server.

2fill in blank

medium

Complete the command to check the status of Cloudera Manager agent.

Hadoop

sudo service cloudera-scm-agent [1]

Drag options to blanks, or click blank then click option'

Astart

Bstatus

Crestart

Dstop

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'start' or 'restart' instead of 'status'.

The status option shows if the Cloudera Manager agent is running.

3fill in blank

hard

Fix the error in the command to restart Ambari agent.

Hadoop

sudo systemctl [1] ambari-agent

Drag options to blanks, or click blank then click option'

Arestart

Bstart

Cstop

Denable

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'start' alone does not restart if already running.

Using 'enable' only sets service to start on boot.

The restart command stops and then starts the service, applying changes immediately.

4fill in blank

hard

Fill both blanks to create a command that checks the Ambari server logs for errors.

Hadoop

sudo tail -n [1] /var/log/ambari-server/ambari-server.[2]

Drag options to blanks, or click blank then click option'

A100

Berror.log

Ccurrent

D50

Attempts:

3 left

💡 Hint

Common Mistakes

Using too few lines like 50 may miss errors.

Using 'error.log' is not the standard log file name.

The command shows the last 100 lines of the current Ambari server log file.

5fill in blank

hard

Fill all three blanks to create a command that lists all running Cloudera Manager services and filters for 'Active'.

Hadoop

sudo systemctl list-units --type=[1] | grep [2] | grep [3]

Drag options to blanks, or click blank then click option'

Aservice

Bcloudera

CActive

Drunning

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'running' instead of 'Active' for filtering status.

Using wrong unit type like 'socket'.

This command lists all services, filters those related to Cloudera, then shows only those that are active.

Practice

1. What is the primary purpose of Ambari or Cloudera Manager in a Hadoop cluster?

easy

A. To replace the Hadoop NameNode

B. To monitor the health and performance of the Hadoop cluster

C. To store data in HDFS

D. To write MapReduce jobs

Solution

1. Step 1: Understand the role of Ambari and Cloudera Manager

   Both tools provide dashboards and monitoring features for Hadoop clusters.

2. Step 2: Identify their main function

   They help track cluster health, performance, and alert on issues.

3. Final Answer:

   To monitor the health and performance of the Hadoop cluster -> Option B

4. Quick Check:

   Monitoring = D [OK]

Hint: They are monitoring tools, not data storage or processing [OK]

Common Mistakes:

• Confusing monitoring with data storage
• Thinking they run MapReduce jobs
• Assuming they replace core Hadoop components

2. Which of the following URLs is typically used to access the Ambari web UI?

easy

A. http://:8080

B. http://:50070

C. http://:7180

D. http://:9000

Solution

1. Step 1: Recall default Ambari server port

   Ambari server's web UI runs on port 8080 by default.

2. Step 2: Differentiate from other ports

   Port 50070 is for HDFS NameNode UI, 7180 is Cloudera Manager, 9000 is HDFS service port.

3. Final Answer:

   http://<ambari-server-host>:8080 -> Option A

4. Quick Check:

   Ambari UI = port 8080 [OK]

Hint: Ambari UI always uses port 8080 by default [OK]

Common Mistakes:

• Confusing Ambari port with Cloudera Manager port
• Using HDFS ports for Ambari UI
• Mixing service ports with UI ports

3. Given the following Ambari REST API call:
curl -u admin:admin http://ambari-server:8080/api/v1/clusters/mycluster/services/HDFS/components/NAMENODE
What information does this command retrieve?

medium

A. List of all services in the cluster

B. Logs of the NameNode component

C. Configuration files of the HDFS service

D. Status and details of the HDFS NameNode component

Solution

1. Step 1: Analyze the API endpoint path

   The URL targets the HDFS service and specifically the NAMENODE component in the cluster.

2. Step 2: Understand REST API purpose

   This call fetches the current status and metadata of the NameNode component.

3. Final Answer:

   Status and details of the HDFS NameNode component -> Option D

4. Quick Check:

   API call to component = status/details [OK]

Hint: API URL ending with component name shows that component's status [OK]

Common Mistakes:

• Assuming it lists all services
• Thinking it returns config files
• Expecting logs from this endpoint

4. You try to access Cloudera Manager UI at http://cloudera-manager:7180 but get a connection refused error. What is the most likely cause?

medium

A. Cloudera Manager server is not running

B. You used the wrong port number

C. The Hadoop cluster is down

D. Your browser does not support HTTPS

Solution

1. Step 1: Understand connection refused error

   This error means no service is listening on the target port.

2. Step 2: Check common causes

   If Cloudera Manager is down, port 7180 won't respond. The port is correct and browser HTTPS support is unrelated.

3. Final Answer:

   Cloudera Manager server is not running -> Option A

4. Quick Check:

   Connection refused = service down [OK]

Hint: Connection refused usually means service is stopped [OK]

Common Mistakes:

• Assuming wrong port without checking
• Blaming Hadoop cluster status
• Thinking browser HTTPS support causes refusal

5. You want to automate alerting when HDFS disk usage exceeds 80% using Ambari. Which approach is best?

hard

A. Write a MapReduce job to scan disk usage

B. Manually check disk usage daily via Ambari UI

C. Configure Ambari Alerts to monitor HDFS disk usage and send notifications

D. Restart NameNode when disk usage is high

Solution

1. Step 1: Identify automation capabilities in Ambari

   Ambari supports alert definitions that monitor metrics and trigger notifications automatically.

2. Step 2: Evaluate options for disk usage alerting

   Configuring alerts is the best automated method; manual checks or MapReduce jobs are inefficient or unrelated.

3. Final Answer:

   Configure Ambari Alerts to monitor HDFS disk usage and send notifications -> Option C

4. Quick Check:

   Use Ambari Alerts for automation [OK]

Hint: Use built-in Ambari Alerts for automatic monitoring [OK]

Common Mistakes:

• Relying on manual checks
• Using MapReduce for monitoring
• Restarting services without cause