Monitoring with Spark History Server in Apache Spark - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the Spark History Server.

Apache Spark

start-history-server.sh --dir [1]

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

A/tmp/spark-events

B/home/user/data

C/var/log/spark/events

D/etc/spark/conf

Attempts:

3 left

💡 Hint

Common Mistakes

Using a directory that does not contain Spark event logs.

Confusing configuration directory with event log directory.

The Spark History Server reads event logs from the directory specified by the --dir option. By default, event logs are stored in /tmp/spark-events.

2fill in blank

medium

Complete the command to enable event logging in Spark configuration.

Apache Spark

spark.eventLog.enabled [1] true

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

A:

B!=

C=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using colon or double equals which are invalid in Spark config.

Using not equals operator which disables the setting.

In Spark configuration files, key-value pairs are set using the equals sign =. To enable event logging, set spark.eventLog.enabled=true.

3fill in blank

hard

Fix the error in the command to view Spark History Server UI on port 18080.

Apache Spark

start-history-server.sh --port [1]

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

A18080

B8080

C80

D9090

Attempts:

3 left

💡 Hint

Common Mistakes

Using the default Spark UI port 8080 instead of the History Server port.

Using common HTTP port 80 which is not used by Spark History Server.

The default port for Spark History Server UI is 18080. Using this port allows you to access the UI correctly.

4fill in blank

hard

Fill both blanks to configure Spark to save event logs in HDFS.

Apache Spark

spark.eventLog.dir [1] hdfs://[2]/spark-logs

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

A=

B:

Cnamenode

Dlocalhost

Attempts:

3 left

💡 Hint

Common Mistakes

Using colon instead of equals sign for assignment.

Using localhost instead of the actual HDFS namenode hostname.

To configure Spark event log directory, use = to assign the value. The HDFS path starts with hdfs://namenode/ where namenode is the HDFS master node.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension filtering jobs with duration greater than 1000 ms.

Apache Spark

filtered_jobs = [1]: job['duration'] [2] 1000 for job in jobs if job['status'] == [3]

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

A{job['id']}

B>

C'SUCCESS'

D[job['id']]

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets which create a list, not a dictionary.

Using wrong comparison operators or missing quotes around 'SUCCESS'.

This dictionary comprehension creates a dictionary with job IDs as keys for jobs that succeeded and have duration greater than 1000 ms.

Practice

1. What is the main purpose of the Spark History Server in monitoring Spark applications?

easy

A. To monitor real-time streaming data only

B. To view details of completed Spark jobs using saved event logs

C. To configure Spark cluster resources dynamically

D. To submit new Spark jobs to the cluster

Solution

1. Step 1: Understand Spark History Server role

   The Spark History Server reads event logs from completed jobs to provide detailed information about them.

2. Step 2: Differentiate from other Spark components

   Unlike job submission or real-time monitoring, it focuses on past job performance using saved logs.

3. Final Answer:

   To view details of completed Spark jobs using saved event logs -> Option B

4. Quick Check:

   Spark History Server = View completed job details [OK]

Hint: History Server shows past jobs, not live or submission tasks [OK]

Common Mistakes:

• Confusing History Server with job submission tools
• Thinking it monitors only live streaming jobs
• Assuming it manages cluster resources

2. Which Spark configuration property must be set to enable event logging for the History Server?

easy

A. spark.sql.shuffle.partitions

B. spark.history.fs.logDirectory

C. spark.executor.memory

D. spark.eventLog.enabled

Solution

1. Step 1: Identify event logging property

   The property spark.eventLog.enabled controls whether Spark saves event logs for completed jobs.

2. Step 2: Differentiate from other configs

   spark.history.fs.logDirectory sets log location, not enabling logging; others relate to memory or shuffle partitions.

3. Final Answer:

   spark.eventLog.enabled -> Option D

4. Quick Check:

   Enable event logging = spark.eventLog.enabled [OK]

Hint: Enable event logging with spark.eventLog.enabled true [OK]

Common Mistakes:

• Confusing log directory with enabling logging
• Choosing unrelated Spark properties
• Assuming memory or shuffle configs enable logging

3. Given the configuration:

spark.eventLog.enabled=true
spark.history.fs.logDirectory=/tmp/spark-events

What will happen after a Spark job finishes?

medium

A. Event logs will be saved to /tmp/spark-events for History Server access

B. No event logs will be saved because logging is disabled

C. Logs will be saved but History Server cannot read them

D. Spark job will fail due to invalid log directory

Solution

1. Step 1: Check event logging enabled

   Since spark.eventLog.enabled=true, Spark saves event logs after job completion.

2. Step 2: Confirm log directory setting

   The logs are saved to /tmp/spark-events, which the History Server reads to show job details.

3. Final Answer:

   Event logs will be saved to /tmp/spark-events for History Server access -> Option A

4. Quick Check:

   Logging enabled + valid directory = logs saved [OK]

Hint: True eventLog.enabled + valid directory = logs saved [OK]

Common Mistakes:

• Assuming logs are not saved if directory is custom
• Thinking logging is off despite true setting
• Believing job fails due to log directory path

4. You started the Spark History Server but see no jobs listed in the UI. Which is the most likely cause?

medium

A. The Spark History Server UI port is blocked by firewall

B. Spark jobs are still running and not completed

C. spark.eventLog.enabled is set to false or event logs are missing

D. The Spark History Server service is running on the wrong machine

Solution

1. Step 1: Check event logging status

   If spark.eventLog.enabled is false or event logs are missing, History Server has no data to show.

2. Step 2: Understand UI port and job status

   Firewall blocking UI port prevents access but not empty job list; running jobs don't appear until finished.

3. Final Answer:

   spark.eventLog.enabled is set to false or event logs are missing -> Option C

4. Quick Check:

   No jobs in UI = logging off or missing logs [OK]

Hint: No jobs shown? Check if event logging is enabled [OK]

Common Mistakes:

• Assuming firewall blocks job list display
• Expecting running jobs to appear in History Server
• Thinking server machine location affects job visibility

5. You want to monitor completed Spark jobs on a cluster. Which sequence of steps correctly sets up the Spark History Server?

hard

A. Enable event logging, set log directory, start History Server, open UI

B. Start History Server, submit jobs, enable event logging, open UI

C. Set log directory, open UI, enable event logging, start History Server

D. Submit jobs, start History Server, set log directory, enable event logging

Solution

1. Step 1: Enable event logging and set log directory

   First, enable spark.eventLog.enabled=true and set spark.history.fs.logDirectory so logs are saved properly.

2. Step 2: Start History Server and open UI

   Then start the History Server to read logs and open its web UI to monitor completed jobs.

3. Final Answer:

   Enable event logging, set log directory, start History Server, open UI -> Option A

4. Quick Check:

   Enable logging + set dir + start server + open UI = monitor jobs [OK]

Hint: Enable logging first, then start History Server and open UI [OK]

Common Mistakes:

• Starting History Server before enabling logging
• Opening UI before logs exist
• Setting log directory after starting server