MirrorMaker 2 concept in Kafka - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary role of MirrorMaker 2 in Kafka?

MirrorMaker 2 is a tool used in Kafka ecosystems. What is its main purpose?

A To manage Kafka topic configurations automatically

B To compress Kafka messages to save storage space

C To monitor Kafka cluster health and performance metrics

D To replicate data between Kafka clusters for disaster recovery and geo-replication

💡 Hint

Think about data movement between clusters.

MirrorMaker 2 is designed to replicate topics between Kafka clusters, enabling disaster recovery and geo-replication.

❓ Predict Output

intermediate

What output does this MirrorMaker 2 configuration produce?

Given this MirrorMaker 2 configuration snippet, what will be the effect?

Kafka

clusters = {
  'primary': {
    'bootstrap.servers': 'primary.kafka:9092'
  },
  'secondary': {
    'bootstrap.servers': 'secondary.kafka:9092'
  }
}

tasks.max = 2

replication.policy.class = org.apache.kafka.connect.mirror.DefaultReplicationPolicy

# Replicate all topics from primary to secondary
source.cluster = primary
target.cluster = secondary

A No topics will be replicated because tasks.max is too low

B Only topics starting with 'primary' will be replicated

C All topics from the primary cluster will be replicated to the secondary cluster

D Topics will be replicated from secondary to primary cluster

💡 Hint

Look at source and target cluster settings.

The configuration sets the source as primary and target as secondary, replicating all topics by default.

🔧 Debug

advanced

Why does this MirrorMaker 2 setup fail to replicate topics?

This MirrorMaker 2 config does not replicate any topics. Identify the cause.

Kafka

clusters = {
  'clusterA': {
    'bootstrap.servers': 'clusterA.kafka:9092'
  },
  'clusterB': {
    'bootstrap.servers': 'clusterB.kafka:9092'
  }
}

tasks.max = 1

replication.policy.class = org.apache.kafka.connect.mirror.DefaultReplicationPolicy

source.cluster = clusterA
target.cluster = clusterB

# Missing topics whitelist filter

A Because no topics are specified in the whitelist, no topics are replicated

B Because tasks.max is set to 1, replication is disabled

C Because replication.policy.class is incorrect, replication fails

D Because source and target clusters are reversed, replication fails

💡 Hint

Check if topics are selected for replication.

MirrorMaker 2 requires a topics whitelist or pattern to know which topics to replicate; without it, no topics are replicated.

📝 Syntax

advanced

Which MirrorMaker 2 configuration snippet is syntactically correct?

Select the configuration snippet that is valid for MirrorMaker 2.

A

clusters = { 'src' => { 'bootstrap.servers' => 'src.kafka:9092' }, 'dest' => { 'bootstrap.servers' => 'dest.kafka:9092' } }
tasks.max=3
source.cluster=src
target.cluster=dest

B

clusters = { 'src': { 'bootstrap.servers': 'src.kafka:9092' }, 'dest': { 'bootstrap.servers': 'dest.kafka:9092' } }
tasks.max=3
source.cluster=src
target.cluster=dest

C

clusters = [ 'src': { 'bootstrap.servers': 'src.kafka:9092' }, 'dest': { 'bootstrap.servers': 'dest.kafka:9092' } ]
tasks.max=3
source.cluster=src
target.cluster=dest

D

clusters = { 'src': { 'bootstrap.servers': 'src.kafka:9092' }, 'dest': { 'bootstrap.servers': 'dest.kafka:9092' } }
tasks.max=three
source.cluster=src
target.cluster=dest

💡 Hint

Look for correct data structure and value types.

Option B uses correct dictionary syntax and numeric value for tasks.max; others have syntax errors or invalid values.

🚀 Application

expert

How does MirrorMaker 2 handle topic offsets during replication?

When MirrorMaker 2 replicates topics between clusters, how does it manage consumer offsets to ensure consumers can continue seamlessly?

A It replicates consumer offsets to the target cluster's __consumer_offsets topic to maintain consumer group state

B It resets all consumer offsets to zero on the target cluster after replication

C It does not replicate offsets; consumers must manually reset offsets on the target cluster

D It stores offsets externally in a separate database outside Kafka

💡 Hint

Think about how consumer groups keep track of their position.

MirrorMaker 2 replicates the __consumer_offsets topic so that consumer groups can continue consuming from the correct position on the target cluster.