---
id: 9830911c-333f-4be1-916c-3317cc4d1b9b
---

# Kafka Data Inconsistencies from Kafka Broker Replication Issues.
---

This incident type refers to situations where data inconsistencies arise due to issues with Kafka broker replication. Kafka brokers are responsible for replicating data across multiple nodes, ensuring that data is available even if one node fails. If there are issues with this replication process, it can result in data inconsistencies, where different nodes have different versions of the same data. This can cause a range of issues, including errors, data corruption, and other problems that can impact the functionality and reliability of the software system.

### Parameters
```shell
export TOPIC_NAME="PLACEHOLDER"

export BROKER_LIST="PLACEHOLDER"

export GROUP_NAME="PLACEHOLDER"

export KAFKA_CONFIG_FILE="PLACEHOLDER"

export DESIRED_REPLICATION_FACTOR="PLACEHOLDER"

export BROKER_ID="PLACEHOLDER"

export PATH_TO_KAFKA_HOME_DIRECTORY="PLACEHOLDER"
```

## Debug

### Check if Kafka broker is up and running
```shell
systemctl status kafka
```

### Check the replication status of Kafka brokers
```shell
kafka-topics --describe --bootstrap-server ${BROKER_LIST} --topic ${TOPIC_NAME}
```

### Check the status of the Kafka consumers
```shell
kafka-consumer-groups --bootstrap-server ${BROKER_LIST} --group ${GROUP_NAME} --describe
```

### Check for any errors in the Kafka logs
```shell
tail -f /var/log/kafka/kafka.log
```

### Check the status of the Kafka producers
```shell
kafka-console-producer --broker-list ${BROKER_LIST} --topic ${TOPIC_NAME}
```

### The Kafka cluster is not configured with enough replication factor, resulting in data inconsistencies when a broker goes down.
```shell


#!/bin/bash



# Set variables

KAFKA_HOME=${PATH_TO_KAFKA_HOME_DIRECTORY}

REPLICATION_FACTOR=${DESIRED_REPLICATION_FACTOR}

BROKER=${BROKER_ID}



# Check current replication factor

CURRENT_REPLICATION_FACTOR=$($KAFKA_HOME/bin/kafka-topics.sh --describe --zookeeper localhost:2181 --topic ${TOPIC_NAME} | awk -F': ' '/^Replication Factor:/ {print $2}')

if [ "$CURRENT_REPLICATION_FACTOR" -lt "$REPLICATION_FACTOR" ]; then

  echo "Replication factor is currently set to $CURRENT_REPLICATION_FACTOR, which is less than desired replication factor of $REPLICATION_FACTOR."

  echo "Please increase the replication factor to at least $REPLICATION_FACTOR to avoid data inconsistencies when a broker goes down."

  exit 1

fi



# Check if broker is down

BROKER_STATUS=$($KAFKA_HOME/bin/kafka-topics.sh --describe --zookeeper localhost:2181 --topic ${TOPIC_NAME} | grep -w isr | grep -w $BROKER | awk '{print $2}')

if [ "$BROKER_STATUS" == "false" ]; then

  echo "Broker $BROKER is currently down. Please bring it back up to avoid data inconsistencies."

  exit 1

fi



echo "System is healthy. No issues detected."

exit 0


```

## Repair

### Check the replication settings and configurations. Ensure that the replication factor is set to a value that can handle the expected load and that the Kafka brokers are properly configured to handle replication.
```shell
bash

#!/bin/bash



# Set the desired replication factor and the location of the Kafka configuration file

REPLICATION_FACTOR=${DESIRED_REPLICATION_FACTOR}

KAFKA_CONFIG=${KAFKA_CONFIG_FILE}



# Update the replication factor in the Kafka configuration file

sed -i "s/replication.factor=.*/replication.factor=$REPLICATION_FACTOR/g" $KAFKA_CONFIG



# Restart the Kafka brokers to apply the updated configuration

sudo systemctl restart kafka


```

This incident type refers to situations where data inconsistencies arise due to issues with Kafka broker replication. Kafka brokers are responsible for replicating data across multiple nodes, ensuring that data is available even if one node fails. If there are issues with this replication process, it can result in data inconsistencies, where different nodes have different versions of the same data. This can cause a range of issues, including errors, data corruption, and other problems that can impact the functionality and reliability of the software system.


This incident type refers to a situation where there is an issue with the communication between Kafka brokers due to network partitioning. A network partition is a situation where a network is split into two or more parts, and communication between them is disrupted. This issue can lead to data inconsistency, loss of messages, delayed message delivery, and other related problems. As a result, it is important to quickly detect and resolve these incidents to prevent any downstream impact on the system.


Parameters

This type of incident occurs when the offset of a Kafka topic decreases unexpectedly. In Kafka, an offset is a unique identifier that represents the position of a message within a partition. When the offset decreases, it means that some messages have been lost or deleted, which can cause data inconsistencies or other issues within the system. This incident type is critical for Kafka-based systems as it affects data integrity and can lead to data loss.


Kafka topic offset decreased incident.

This incident type refers to when a Kafka node runs out of storage space to store data. This can cause issues with data processing and storage, potentially leading to data loss and system downtime.


Kafka node insufficient storage check

This incident type refers to a scenario where the liveness check for Kafka cannot reach/communicate with the host where the broker is running. This issue can arise due to various reasons such as network issues, broker failure, or configuration errors. This can result in the Kafka broker being unavailable or not responding to requests, leading to potential service disruptions or downtime.


Kafka liveness check failure.

```shell
export TOPIC_NAME="PLACEHOLDER"

export BROKER_LIST="PLACEHOLDER"

export GROUP_NAME="PLACEHOLDER"

export KAFKA_CONFIG_FILE="PLACEHOLDER"

export DESIRED_REPLICATION_FACTOR="PLACEHOLDER"

export BROKER_ID="PLACEHOLDER"

export PATH_TO_KAFKA_HOME_DIRECTORY="PLACEHOLDER"
```


### Check if Kafka broker is up and running

```shell
systemctl status kafka
```

### Check the replication status of Kafka brokers

```shell
kafka-topics --describe --bootstrap-server ${BROKER_LIST} --topic ${TOPIC_NAME}
```

### Check the status of the Kafka consumers

```shell
kafka-consumer-groups --bootstrap-server ${BROKER_LIST} --group ${GROUP_NAME} --describe
```

### Check for any errors in the Kafka logs

```shell
tail -f /var/log/kafka/kafka.log
```

### Check the status of the Kafka producers

```shell
kafka-console-producer --broker-list ${BROKER_LIST} --topic ${TOPIC_NAME}
```

### The Kafka cluster is not configured with enough replication factor, resulting in data inconsistencies when a broker goes down.

```shell


#!/bin/bash



# Set variables

KAFKA_HOME=${PATH_TO_KAFKA_HOME_DIRECTORY}

REPLICATION_FACTOR=${DESIRED_REPLICATION_FACTOR}

BROKER=${BROKER_ID}



# Check current replication factor

CURRENT_REPLICATION_FACTOR=$($KAFKA_HOME/bin/kafka-topics.sh --describe --zookeeper localhost:2181 --topic ${TOPIC_NAME} | awk -F': ' '/^Replication Factor:/ {print $2}')

if [ "$CURRENT_REPLICATION_FACTOR" -lt "$REPLICATION_FACTOR" ]; then

  echo "Replication factor is currently set to $CURRENT_REPLICATION_FACTOR, which is less than desired replication factor of $REPLICATION_FACTOR."

  echo "Please increase the replication factor to at least $REPLICATION_FACTOR to avoid data inconsistencies when a broker goes down."

  exit 1

fi



# Check if broker is down

BROKER_STATUS=$($KAFKA_HOME/bin/kafka-topics.sh --describe --zookeeper localhost:2181 --topic ${TOPIC_NAME} | grep -w isr | grep -w $BROKER | awk '{print $2}')

if [ "$BROKER_STATUS" == "false" ]; then

  echo "Broker $BROKER is currently down. Please bring it back up to avoid data inconsistencies."

  exit 1

fi



echo "System is healthy. No issues detected."

exit 0


```


### Check the replication settings and configurations. Ensure that the replication factor is set to a value that can handle the expected load and that the Kafka brokers are properly configured to handle replication.

```shell
bash

#!/bin/bash



# Set the desired replication factor and the location of the Kafka configuration file

REPLICATION_FACTOR=${DESIRED_REPLICATION_FACTOR}

KAFKA_CONFIG=${KAFKA_CONFIG_FILE}



# Update the replication factor in the Kafka configuration file

sed -i "s/replication.factor=.*/replication.factor=$REPLICATION_FACTOR/g" $KAFKA_CONFIG



# Restart the Kafka brokers to apply the updated configuration

sudo systemctl restart kafka


```


Kafka Data Inconsistencies from Kafka Broker Replication Issues.

Overview

Parameters

Debug

Check if Kafka broker is up and running

Check the replication status of Kafka brokers

Check the status of the Kafka consumers

Check for any errors in the Kafka logs

Check the status of the Kafka producers

The Kafka cluster is not configured with enough replication factor, resulting in data inconsistencies when a broker goes down.

Repair

Check the replication settings and configurations. Ensure that the replication factor is set to a value that can handle the expected load and that the Kafka brokers are properly configured to handle replication.

Learn more

Related Runbooks

Network Partitioning Between Kafka Brokers.

Parameters

Kafka topic offset decreased incident.

Kafka node insufficient storage check

Support