---
id: c12fb176-616d-11ee-8c99-0242ac120002
---

# Cassandra Version Mismatch Remediation in Cluster.
---

Cassandra Version Mismatch Remediation in Cluster is an incident type that occurs when there is a discrepancy in the version of Cassandra installed across a cluster. This can lead to various issues, such as data inconsistencies, node failures, and performance degradation. The incident requires a remediation process to resolve the issue, which may involve upgrading or downgrading Cassandra versions, ensuring consistency across all nodes, and verifying successful synchronization of data. It is essential to address this incident type promptly to prevent further complications and ensure the continuous availability of the cluster.

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

export TABLE_NAME="PLACEHOLDER"

export NODE1_NODE2_NODE3="PLACEHOLDER"

export LATEST_VERSION="PLACEHOLDER"

export LINK_TO_LATEST_CASSANDRA_VERSION="PLACEHOLDER"

export CASSANDRA_TARBALL_NAME="PLACEHOLDER"

export CASSANDRA_VERSION="PLACEHOLDER"
```

## Debug

### Check Cassandra version on all nodes
```shell
nodetool version
```

### Check status of all nodes in the cluster
```shell
nodetool status
```

### Check the schema version of the cluster
```shell
nodetool describecluster
```

### Check the difference in schema version across nodes
```shell
nodetool describekeyspace ${KEYSPACE_NAME}
```

### Check the difference in schema version across datacenters
```shell
nodetool describecluster
```

### Check the logs for errors related to Cassandra version mismatch
```shell
grep -r "version mismatch" /var/log/cassandra/system.log
```

### Check the logs for other errors or warnings related to Cassandra
```shell
grep -r "ERROR\|WARN" /var/log/cassandra/system.log
```

### Check the consistency level of the data on all nodes
```shell
nodetool consistency ${KEYSPACE_NAME}.${TABLE_NAME}
```

### Check the repair status of the nodes
```shell
nodetool repair -pr
```

### Check the status of the node's anti-entropy service
```shell
nodetool getsstables ${KEYSPACE_NAME} ${TABLE_NAME} | xargs nodetool scrub
```

### Check the status of the node's incremental repair service
```shell
nodetool verify -pr
```

### A new version of Cassandra was installed on a few nodes, but not all of them, resulting in a version mismatch.
```shell


#!/bin/bash



# Define variables


nodes=${NODE1_NODE2_NODE3}  # Replace with the nodes you want to check



# Loop through nodes and check Cassandra version

for node in ${NODE1_NODE2_NODE3}

do

  version=$(ssh $node "cassandra -v | awk '{ print \$NF }'")  # Get Cassandra version on node

  if [[ $version == $cassandra_version ]]

  then

    echo "Node $node is running the correct version of Cassandra."

  else

    echo "Node $node is running a different version of Cassandra."

  fi

done


```

## Repair

### Upgrade all nodes to the latest version of Cassandra, ensuring that the upgrade process is completed successfully.
```shell


#!/bin/bash



# set the Cassandra version to upgrade to

CASSANDRA_VERSION=${LATEST_VERSION}



# loop through all nodes in the cluster

for node in ${NODE1_NODE2_NODE3}

do

    # check if the node is already running the latest version

    if nodetool -h $node version | grep -q $CASSANDRA_VERSION

    then

        echo "Node $node is already running the latest version of Cassandra"

    else

        # stop Cassandra service on the node

        ssh $node sudo service cassandra stop

        # download and install the latest version of Cassandra on the node

        ssh $node wget ${LINK_TO_LATEST_CASSANDRA_VERSION}

        ssh $node tar zxf ${CASSANDRA_TARBALL_NAME}.tar.gz

        ssh $node sudo mkdir -p /opt/cassandra

        ssh $node sudo mv ${CASSANDRA_TARBALL_NAME} /opt/cassandra

        # update the symbolic link to point to the new version of Cassandra

        ssh $node sudo ln -sfn /opt/cassandra/${CASSANDRA_VERSION} /opt/cassandra/current

        # start Cassandra service on the node

        ssh $node sudo service cassandra start

        echo "Upgraded Cassandra version on node $node to $CASSANDRA_VERSION"

    fi

done


```


Cassandra Version Mismatch Remediation in Cluster is an incident type that occurs when there is a discrepancy in the version of Cassandra installed across a cluster. This can lead to various issues, such as data inconsistencies, node failures, and performance degradation. The incident requires a remediation process to resolve the issue, which may involve upgrading or downgrading Cassandra versions, ensuring consistency across all nodes, and verifying successful synchronization of data. It is essential to address this incident type promptly to prevent further complications and ensure the continuous availability of the cluster.


This incident type refers to a problem in a Cassandra cluster where the token range imbalances cause uneven distribution of data across the cluster. This can result in slower read and write performance that can impact the overall functionality of the system. Token range imbalances occur when the distribution of the tokens that define the ranges of data each node is responsible for is not evenly spread across the cluster. As a result, certain nodes may be responsible for a disproportionate amount of data, leading to performance issues and potential failure of the system.


Token Range Imbalances Causing Uneven Data Distribution and Performance Issues in Cassandra Cluster

This incident type refers to a situation where there is a significant delay in the execution of queries on a Cassandra cluster. This delay can cause the system to become unresponsive and result in slower performance. It may be caused by a variety of factors such as an increase in traffic, inefficient queries, or hardware issues. The issue can impact the functionality of the system and requires immediate attention to prevent further disruption.


Slow Query Performance on Cassandra Cluster.

This incident type refers to a performance degradation issue in a Cassandra database caused by the new generation garbage collection (GC) process. Garbage collection is a process by which the unused memory occupied by objects in a program is cleared. In some cases, the new generation GC process may take longer than usual, causing performance issues in the Cassandra database. This could lead to slowness in queries or even crashing of the database.


Performance Degradation Due to New Generation Garbage Collection on Cassandra

This incident type refers to the issue of missing JMX metrics for Cassandra on a dashboard. JMX metrics are important for monitoring the performance of Cassandra, and their absence on a dashboard can lead to difficulties in identifying and resolving issues that may arise. This incident requires investigation to determine the cause of the issue and to restore the missing metrics to the dashboard.


Missing Cassandra JMX Metrics on Dashboard

This incident type refers to a situation where a high number of mutations are being dropped on a Cassandra database. Mutations are changes made to the database, such as inserting new data or updating existing data. When mutations are dropped, it means that they were not successfully recorded in the database. This can be caused by a variety of factors, such as hardware or network issues, configuration problems, or bugs in the software. When this occurs, it can result in data inconsistencies or loss, and can impact the performance and reliability of the application that relies on the database.


High Number of Dropped Mutations on Cassandra Database

```shell
export KEYSPACE_NAME="PLACEHOLDER"

export TABLE_NAME="PLACEHOLDER"

export NODE1_NODE2_NODE3="PLACEHOLDER"

export LATEST_VERSION="PLACEHOLDER"

export LINK_TO_LATEST_CASSANDRA_VERSION="PLACEHOLDER"

export CASSANDRA_TARBALL_NAME="PLACEHOLDER"

export CASSANDRA_VERSION="PLACEHOLDER"
```


### Check Cassandra version on all nodes

```shell
nodetool version
```

### Check status of all nodes in the cluster

```shell
nodetool status
```

### Check the schema version of the cluster

```shell
nodetool describecluster
```

### Check the difference in schema version across nodes

```shell
nodetool describekeyspace ${KEYSPACE_NAME}
```

### Check the difference in schema version across datacenters

```shell
nodetool describecluster
```

### Check the logs for errors related to Cassandra version mismatch

```shell
grep -r "version mismatch" /var/log/cassandra/system.log
```

### Check the logs for other errors or warnings related to Cassandra

```shell
grep -r "ERROR\|WARN" /var/log/cassandra/system.log
```

### Check the consistency level of the data on all nodes

```shell
nodetool consistency ${KEYSPACE_NAME}.${TABLE_NAME}
```

### Check the repair status of the nodes

```shell
nodetool repair -pr
```

### Check the status of the node's anti-entropy service

```shell
nodetool getsstables ${KEYSPACE_NAME} ${TABLE_NAME} | xargs nodetool scrub
```

### Check the status of the node's incremental repair service

```shell
nodetool verify -pr
```

### A new version of Cassandra was installed on a few nodes, but not all of them, resulting in a version mismatch.

```shell


#!/bin/bash



# Define variables


nodes=${NODE1_NODE2_NODE3}  # Replace with the nodes you want to check



# Loop through nodes and check Cassandra version

for node in ${NODE1_NODE2_NODE3}

do

  version=$(ssh $node "cassandra -v | awk '{ print \$NF }'")  # Get Cassandra version on node

  if [[ $version == $cassandra_version ]]

  then

    echo "Node $node is running the correct version of Cassandra."

  else

    echo "Node $node is running a different version of Cassandra."

  fi

done


```


### Upgrade all nodes to the latest version of Cassandra, ensuring that the upgrade process is completed successfully.

```shell


#!/bin/bash



# set the Cassandra version to upgrade to

CASSANDRA_VERSION=${LATEST_VERSION}



# loop through all nodes in the cluster

for node in ${NODE1_NODE2_NODE3}

do

    # check if the node is already running the latest version

    if nodetool -h $node version | grep -q $CASSANDRA_VERSION

    then

        echo "Node $node is already running the latest version of Cassandra"

    else

        # stop Cassandra service on the node

        ssh $node sudo service cassandra stop

        # download and install the latest version of Cassandra on the node

        ssh $node wget ${LINK_TO_LATEST_CASSANDRA_VERSION}

        ssh $node tar zxf ${CASSANDRA_TARBALL_NAME}.tar.gz

        ssh $node sudo mkdir -p /opt/cassandra

        ssh $node sudo mv ${CASSANDRA_TARBALL_NAME} /opt/cassandra

        # update the symbolic link to point to the new version of Cassandra

        ssh $node sudo ln -sfn /opt/cassandra/${CASSANDRA_VERSION} /opt/cassandra/current

        # start Cassandra service on the node

        ssh $node sudo service cassandra start

        echo "Upgraded Cassandra version on node $node to $CASSANDRA_VERSION"

    fi

done


```


Cassandra Version Mismatch Remediation in Cluster.

Overview

Parameters

Debug

Check Cassandra version on all nodes

Check status of all nodes in the cluster

Check the schema version of the cluster

Check the difference in schema version across nodes

Check the difference in schema version across datacenters

Check the consistency level of the data on all nodes

Check the repair status of the nodes

Check the status of the node's anti-entropy service

Check the status of the node's incremental repair service

A new version of Cassandra was installed on a few nodes, but not all of them, resulting in a version mismatch.

Repair

Upgrade all nodes to the latest version of Cassandra, ensuring that the upgrade process is completed successfully.

Learn more

Related Runbooks

Token Range Imbalances Causing Uneven Data Distribution and Performance Issues in Cassandra Cluster

Slow Query Performance on Cassandra Cluster.

Performance Degradation Due to New Generation Garbage Collection on Cassandra

Missing Cassandra JMX Metrics on Dashboard

Support