MirrorMaker 2 concept in Kafka - Step-by-Step Execution

Process Flow - MirrorMaker 2 concept

Start MirrorMaker 2

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Connect to Source Cluster

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Read Topics from Source

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Apply Filters and Transformations

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Produce to Target Cluster

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Monitor Replication Status

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Handle Failures and Retries

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End

MirrorMaker 2 connects two Kafka clusters, reads topics from the source, optionally transforms data, and writes it to the target cluster while monitoring and handling errors.

Execution Sample

Kafka

connect source_cluster
read topic 'orders'
filter messages with key 'user'
produce to target_cluster
monitor replication
handle errors

This sequence shows MirrorMaker 2 connecting to a source cluster, reading a topic, filtering messages, sending them to a target cluster, and monitoring the process.

Process Table

Step	Action	Details	Result
1	Connect to source cluster	Connect to kafka-source.example.com	Connection established
2	Read topic	Read messages from 'orders' topic	Messages fetched
3	Filter messages	Keep messages with key 'user'	Filtered messages ready
4	Produce to target cluster	Send filtered messages to kafka-target.example.com	Messages produced
5	Monitor replication	Check offsets and lag	Replication healthy
6	Handle errors	Retry on failure	Errors handled or logged
7	End	Replication complete or stopped	Process ends

💡 Replication ends when stopped manually or on unrecoverable error

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	After Step 5	Final
connection_status	disconnected	connected	connected	connected	connected	disconnected
messages_fetched	0	1000	1000	1000	1000	0
messages_filtered	0	0	600	600	600	0
messages_produced	0	0	0	600	600	600
replication_health	unknown	unknown	unknown	unknown	healthy	stopped

Key Moments - 3 Insights

Why do we filter messages after reading them from the source?

Filtering happens after reading to select only relevant messages for replication, as shown in step 3 of the execution_table where messages are filtered by key.

What happens if the connection to the target cluster fails during production?

MirrorMaker 2 retries sending messages and handles errors as shown in step 6, ensuring replication continues or logs failures.

When does the replication process stop?

Replication stops manually or on unrecoverable errors as noted in the exit_note and step 7 of the execution_table.

Visual Quiz - 3 Questions

Look at the execution_table, what is the number of messages filtered after step 3?

A 600

B 1000

C 0

D 400

💡 Hint

Check the 'messages_filtered' variable in variable_tracker after step 3

At which step does MirrorMaker 2 check the replication health?

A Step 4

B Step 2

C Step 5

D Step 6

💡 Hint

Look at the 'Monitor replication' action in the execution_table

If the connection to the source cluster fails at step 1, what happens next?

A Replication proceeds without source connection

B Process cannot continue and stops

C Messages are filtered anyway

D Messages are produced to target cluster

💡 Hint

Refer to step 1 in execution_table where connection is established; failure means no further steps

Concept Snapshot

MirrorMaker 2 replicates Kafka topics between clusters.
It connects to source, reads topics, filters or transforms messages.
Then it produces messages to the target cluster.
It monitors replication health and handles errors.
Replication stops manually or on unrecoverable errors.

Full Transcript

MirrorMaker 2 is a tool that copies data from one Kafka cluster to another. It starts by connecting to the source cluster, then reads messages from specified topics. After reading, it can filter or transform messages before sending them to the target cluster. During this process, it monitors the replication status to ensure data is copied correctly. If errors happen, it retries or logs them. The process continues until stopped manually or if a serious error occurs.