Updating Cassandra

Checking the Cassandra version

It is recommended to periodically update your Cassandra database. This will ensure that all known vulnerabilities are fixed.

To check the Cassandra version, go to C:\Program Files\Cassandra\bin and execute the following nodetool command:

.\nodetool version

With recent DataMiner versions, Cassandra 3.11 is installed by default. This is also the minimum supported version. Cassandra 4.0 is also supported.

Note

Cassandra 4.0 no longer supports Windows. This means that extra Linux servers will be required to host the Cassandra database.

Tip

To limit the impact of a breach through Cassandra, it is recommended to run the Cassandra service as a non-SYSTEM user. For more details, see Running Cassandra as non-SYSTEM user.

Updating the Cassandra version

As with all software, it is good practice to ensure you are running the latest version to minimize the number of known vulnerabilities.

Tip

A PowerShell script is available to update Cassandra easily. For more details see Cassandra Hardening.

To update the Cassandra version:

  1. Ensure you have a full backup of the Cassandra database.

  2. Download the latest Cassandra 3.11.X binaries from the official website and extract the archive.

  3. Stop the DataMiner Agent.

  4. Go to the C:\Program Files\Cassandra\bin folder and run the following command to push all data from memory to disk and stop processing new requests:

    .\nodetool drain

  5. Stop the Cassandra service.

  6. Rename the C:\Program Files\Cassandra folder to Cassandra_bak.

  7. Create a new folder named Cassandra in C:\Program Files.

  8. Copy the downloaded Cassandra binaries to this new Cassandra folder.

  9. Copy the old Java folder from C:\Program Files\Cassandra_bak\Java to C:\Program Files\Cassandra.

  10. Copy the old cassandra.yaml from C:\Program Files\Cassandra_bak\conf\cassandra.yaml to C:\Program Files\Cassandra\conf.

  11. Copy the old daemon folder from C:\Program Files\Cassandra_bak\bin\daemon to C:\Program Files\Cassandra\bin.

  12. Copy the old DevCenter folder from C:\Program Files\Cassandra_bak\DevCenter to C:\Program Files\Cassandra.

  13. Create a new folder named logs in C:\Program Files\Cassandra.

  14. To enable the use of nodetool, set the system-wide environment variables JAVA_HOME and CASSANDRA_HOME to the correct locations by executing the following PowerShell commands:

    [System.Environment]::SetEnvironmentVariable('CASSANDRA_HOME','C:\progra~1\Cassandra\',[System.EnvironmentVariableTarget]::Machine)

    [System.Environment]::SetEnvironmentVariable('JAVA_HOME','C:\progra~1\Cassandra\Java\',[System.EnvironmentVariableTarget]::Machine)

  15. Open a PowerShell prompt (as Administrator) and execute the following command to register the Cassandra service:

    cd 'C:\Program Files\Cassandra\bin\'; .\cassandra.ps1 -install

  16. To make sure the location of the Jvm is correctly set in the registry, execute the following PowerShell command:

    Set-ItemProperty -Path "HKLM:\SOFTWARE\WOW6432Node\Apache Software Foundation\Procrun 2.0\cassandra\Parameters\Java" -Name "Jvm" -Value "C:\Program Files\Cassandra\Java\bin\server\jvm.dll"

  17. To prevent startup issues, DataMiner enables the commitlog.ignorereplayerrors option in Cassandra. Make sure this is set by executing the following PowerShell commands:

    $options = Get-ItemProperty -Path "HKLM:\SOFTWARE\WOW6432Node\Apache Software Foundation\Procrun 2.0\cassandra\Parameters\Java" -Name "Options"

    $options.Options += "-Dcassandra.commitlog.ignorereplayerrors=true"

    Set-ItemProperty -Path "HKLM:\SOFTWARE\WOW6432Node\Apache Software Foundation\Procrun 2.0\cassandra\Parameters\Java" -Name "Options" -Value $options.Options

  18. Verify that the Cassandra service has been created and that it can be started from the Task Manager (or the Services Manager).

  19. After a Cassandra upgrade, it is (sometimes) necessary to execute nodetool upgradesstables on your nodes to convert sstables to the new Cassandra version. Go to the C:\Program Files\Cassandra\bin folder and run the following command:

    .\nodetool upgradesstables

    Warning

    Depending on the size of your database, converting the sstables can take a while.

  20. Start the DataMiner Agent and make sure that no error alarms are visible in the Alarm Console.

Tip

After starting the Cassandra service, verify that the expected Cassandra version is logged in C:\Program Files\Cassandra\Logs\system.log. For example: Cassandra version: 3.11.12 If the service does not start and no logs are created, make sure that the Jvm registry key refers to the correct location. Execute nodetool status to check whether the system is running stable.