Monitoring with Spark History Server in Apache Spark - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the Spark History Server used for?

The Spark History Server lets you see details about completed Spark jobs. It helps you check job progress, errors, and performance after the job finishes.

beginner

Where does Spark History Server get the data to show job details?

It reads event logs saved by Spark jobs in a configured storage location, like HDFS or a local directory.

intermediate

How do you enable event logging for Spark jobs to be visible in the History Server?

Set the configuration spark.eventLog.enabled to true and specify spark.eventLog.dir to a storage path before running your Spark job.

intermediate

What information can you find in the Spark History Server UI?

You can see job timelines, stages, tasks, executors, and detailed metrics like duration, shuffle read/write, and errors.

beginner

How do you start the Spark History Server?

Run the command: ./sbin/start-history-server.sh from your Spark installation directory. It will start a web UI to monitor past jobs.

What must be enabled for Spark History Server to show job details?

A spark.eventLog.enabled

B spark.history.enabled

C spark.ui.enabled

D spark.job.monitoring

spark.eventLog.enabled must be true to save event logs for the History Server.

Where does Spark History Server read event logs from?

A From the Spark driver memory

B From the configured event log directory

C From the Spark executor logs

D From the Spark UI cache

It reads event logs from the directory set in spark.eventLog.dir.

Which command starts the Spark History Server?

A ./bin/start-spark-history.sh

B start-spark-history-server

C spark-history-server start

D ./sbin/start-history-server.sh

The correct command is ./sbin/start-history-server.sh.

What kind of information can you NOT find in the Spark History Server UI?

A Real-time job progress

B Job timelines and stages

C Executor metrics and task details

D Error messages from completed jobs

The History Server shows completed job info, not real-time progress.

If you want to change where Spark saves event logs, which config do you update?

A spark.log.dir

B spark.history.dir

C spark.eventLog.dir

D spark.history.log.path

spark.eventLog.dir sets the directory for event logs.

Explain how to set up Spark to use the History Server for monitoring completed jobs.

Think about configuration, starting the server, and viewing results.

Describe what kind of job information you can find in the Spark History Server UI and why it is useful.

Focus on the types of data and their purpose.

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