Broker configuration basics in Kafka - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this broker configuration snippet?

Given the following Kafka broker configuration snippet, what will be the value of log.retention.hours after applying it?

Kafka

log.retention.hours=168
log.retention.minutes=10080

A Default value 168 is used, minutes setting ignored

B 10080

C Both 168 and 10080 are applied, minutes override hours

D 168

💡 Hint

Kafka uses the most specific time unit setting for retention. If both hours and minutes are set, the hours setting takes precedence.

Kafka broker configuration prioritizes the most specific time unit. Here, log.retention.hours is set to 168 hours (7 days). The log.retention.minutes setting is ignored because log.retention.hours is present.

❓ Predict Output

intermediate

What happens if num.network.threads is set to 0?

Consider this Kafka broker configuration line:

num.network.threads=0

What will happen when the broker starts?

Kafka

num.network.threads=0

A Broker fails to start with a configuration error

B Broker starts but network threads default to 1

C Broker starts but logs a warning and uses 2 network threads

D Broker starts normally with zero network threads

💡 Hint

Some thread count settings must be positive integers.

Kafka requires num.network.threads to be a positive integer. Setting it to 0 causes a configuration validation failure and the broker will not start.

🔧 Debug

advanced

Why does the broker ignore the log.segment.bytes setting?

A user sets the following in server.properties:

log.segment.bytes=1073741824
log.segment.ms=604800000

But the broker still creates log segments smaller than 1GB. What is the most likely reason?

Kafka

log.segment.bytes=1073741824
log.segment.ms=604800000

A The <code>log.segment.ms</code> setting causes segments to roll over by time before size is reached

B The <code>log.segment.bytes</code> value is too large and ignored by Kafka

C The broker requires a restart to apply <code>log.segment.bytes</code>

D The <code>log.segment.bytes</code> setting must be in MB, not bytes

💡 Hint

Kafka rolls log segments based on whichever limit is reached first: size or time.

Kafka rolls over log segments when either the size limit (log.segment.bytes) or the time limit (log.segment.ms) is reached. Here, the time limit causes segments to roll over before reaching 1GB size.

📝 Syntax

advanced

Which configuration line is syntactically correct for setting broker ID?

Choose the correct syntax to set the broker ID to 5 in server.properties:

A broker id=5

B broker.id:5

C broker.id=5

D broker.id = 5

💡 Hint

Kafka configuration uses key=value pairs without spaces around the equals sign.

Kafka broker configuration requires no spaces around the equals sign. The correct syntax is broker.id=5.

🚀 Application

expert

How many log directories will Kafka use with this configuration?

Given this Kafka broker configuration:

log.dirs=/kafka-logs-1,/kafka-logs-2,/kafka-logs-3

How many separate log directories will the broker use to store data?

Kafka

log.dirs=/kafka-logs-1,/kafka-logs-2,/kafka-logs-3

A 1

B 3

C 2

D Depends on the number of partitions

💡 Hint

Kafka splits partitions across all directories listed in log.dirs.

Kafka uses all directories listed in log.dirs to store partitions. Here, three directories are specified, so the broker will use three separate log directories.