PLEASE NOTE: This document applies to an unreleased version of Rook. It is strongly recommended that you only use official releases of Rook, as unreleased versions are subject to changes and incompatibilities that will not be supported in the official releases.

    Cassandra Quickstart

    The Rook Cassandra operator is deprecated

    Welcome to Rook! We hope you have a great experience installing the Rook cloud-native storage orchestrator platform to enable highly available, durable storage in your Kubernetes cluster.

    Cassandra is a highly available, fault tolerant, peer-to-peer NoSQL database featuring lightning fast performance and tunable consistency. It provides massive scalability with no single point of failure.

    Scylla is a close-to-the-hardware rewrite of Cassandra in C++. It features a shared nothing architecture that enables true linear scaling and major hardware optimizations that achieve ultra-low latencies and extreme throughput. It is a drop-in replacement for Cassandra and uses the same interfaces, so it is also supported by Rook.

    If you have any questions along the way, please don’t hesitate to ask us in our Slack channel. You can sign up for our Slack here.

    Deploy Cassandra Operator

    First deploy the Rook Cassandra Operator using the following commands:

    $ git clone --single-branch --branch release-latest
    cd rook/cluster/examples/kubernetes/cassandra
    kubectl apply -f crds.yaml
    kubectl apply -f operator.yaml

    This will install the operator in namespace rook-cassandra-system. You can check if the operator is up and running with:

    kubectl -n rook-cassandra-system get pod

    Create and Initialize a Cassandra/Scylla Cluster

    Now that the operator is running, we can create an instance of a Cassandra/Scylla cluster by creating an instance of the resource. Some of that resource’s values are configurable, so feel free to browse cluster.yaml and tweak the settings to your liking. Full details for all the configuration options can be found in the Cassandra Cluster CRD documentation.

    When you are ready to create a Cassandra cluster, simply run:

    kubectl create -f cluster.yaml

    We can verify that a Kubernetes object has been created that represents our new Cassandra cluster with the command below. This is important because it shows that Rook has successfully extended Kubernetes to make Cassandra clusters a first class citizen in the Kubernetes cloud-native environment.

    kubectl -n rook-cassandra get

    To check if all the desired members are running, you should see the same number of entries from the following command as the number of members that was specified in cluster.yaml:

    kubectl -n rook-cassandra get pod -l app=rook-cassandra

    You can also track the state of a Cassandra cluster from its status. To check the current status of a Cluster, run:

    kubectl -n rook-cassandra describe rook-cassandra

    Accessing the Database

    • From kubectl:

    To get a cqlsh shell in your new Cluster:

    kubectl exec -n rook-cassandra -it rook-cassandra-east-1-east-1a-0 -- cqlsh
    • From inside a Pod:

    When you create a new Cluster, Rook automatically creates a Service for the clients to use in order to access the Cluster. The service’s name follows the convention <cluster-name>-client. You can see this Service in you cluster by running:

    kubectl -n rook-cassandra describe service rook-cassandra-client

    Pods running inside the Kubernetes cluster can use this Service to connect to Cassandra. Here’s an example using the Python Driver:

    from cassandra.cluster import Cluster
    cluster = Cluster(['rook-cassandra-client.rook-cassandra.svc.cluster.local'])
    session = cluster.connect()

    Scale Up

    The operator supports scale up of a rack as well as addition of new racks. To make the changes, you can use:

    kubectl edit rook-cassandra
    • To scale up a rack, change the Spec.Members field of the rack to the desired value.
    • To add a new rack, append the racks list with a new rack. Remember to choose a different rack name for the new rack.
    • After editing and saving the yaml, check your cluster’s Status and Events for information on what’s happening:
    kubectl -n rook-cassandra describe rook-cassandra

    Scale Down

    The operator supports scale down of a rack. To make the changes, you can use:

    kubectl edit rook-cassandra
    • To scale down a rack, change the Spec.Members field of the rack to the desired value.
    • After editing and saving the yaml, check your cluster’s Status and Events for information on what’s happening:
    kubectl -n rook-cassandra describe rook-cassandra

    Clean Up

    To clean up all resources associated with this walk-through, you can run the commands below.

    NOTE: that this will destroy your database and delete all of its associated data.

    kubectl delete -f cluster.yaml
    kubectl delete -f operator.yaml
    kubectl delete -f crds.yaml


    If the cluster does not come up, the first step would be to examine the operator’s logs:

    kubectl -n rook-cassandra-system logs -l app=rook-cassandra-operator

    If everything looks OK in the operator logs, you can also look in the logs for one of the Cassandra instances:

    kubectl -n rook-cassandra logs rook-cassandra-0

    Cassandra Monitoring

    To enable jmx_exporter for cassandra rack, you should specify jmxExporterConfigMapName option for rack in CassandraCluster CRD.

    For example:

    kind: Cluster
      name: my-cassandra
      namespace: rook-cassandra
        name: my-datacenter
        - name: my-rack
          members: 3
          jmxExporterConfigMapName: jmx-exporter-settings
            - metadata:
                name: rook-cassandra-data
                storageClassName: my-storage-class
                    storage: 200Gi

    Simple config map example to get all metrics:

    apiVersion: v1
    kind: ConfigMap
      name: jmx-exporter-settings
      namespace: rook-cassandra
      jmx_exporter_config.yaml: |
        lowercaseOutputLabelNames: true
        lowercaseOutputName: true
        whitelistObjectNames: ["org.apache.cassandra.metrics:*"]

    ConfigMap’s data field must contain jmx_exporter_config.yaml key with jmx exporter settings.

    There is no automatic reloading mechanism for pods when the config map updated. After the configmap changed, you should restart all rack pods manually:

    RACKS=$(kubectl get sts -n ${NAMESPACE} -l "${CLUSTER}")
    echo ${RACKS} | xargs -n1 kubectl rollout restart -n ${NAMESPACE}