Version: 3.1

Install

Prerequisites

You must have a Kubernetes cluster with a minimum of three worker nodes.
Portworx is installed on your Kubernetes cluster. For details about how you can install Portworx on Kubernetes, see the Portworx on Kubernetes page.
You must have Stork installed on your Kubernetes cluster. For details about how you can install Stork, see the Stork page.

Install Cassandra

Enter the following kubectl apply command to create a headless service:

kubectl apply -f - <<EOF
apiVersion: v1
kind: Service
metadata:
  labels:
    app: cassandra
  name: cassandra
spec:
  clusterIP: None
  ports:
    - port: 9042
  selector:
    app: cassandra
EOF

service/cassandra created

Note the following about this service:

The spec.clusterIP field is set to None.
The spec.selector.app field is set to cassandra. The Kubernetes endpoints controller will configure the DNS to return addresses that point directly to your Cassandra Pods.

Use the following kubectl apply command to create a storage class:

kubectl apply -f - <<EOF
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: portworx-sc
provisioner: pxd.portworx.com
parameters:
  repl: "1"
  priority_io: "high"
  group: "cassandra_vg"
  fg: "true"
EOF

storageclass.storage.k8s.io/px-storageclass created

Note the following about this storage class:

The provisioner field is set to pxd.portworx.com. For details about the Portworx-specific parameters, refer to the Portworx Volume section of the Kubernetes documentation
The name of the StorageClass object is portworx-sc
Portworx will create one replica of each volume
Portworx will use a high priority storage pool

The following command creates a stateful set with three replicas and uses the STORK scheduler to place your Pods closer to where their data is located:

kubectl apply -f - <<EOF
apiVersion: "apps/v1"
kind: StatefulSet
metadata:
  name: cassandra
spec:
  selector:
    matchLabels:
      app: cassandra
  serviceName: cassandra
  replicas: 3
  template:
    metadata:
      labels:
        app: cassandra
    spec:
      schedulerName: stork
      containers:
      - name: cassandra
        image: gcr.io/google-samples/cassandra:v12
        imagePullPolicy: Always
        ports:
        - containerPort: 7000
          name: intra-node
        - containerPort: 7001
          name: tls-intra-node
        - containerPort: 7199
          name: jmx
        - containerPort: 9042
          name: cql
        resources:
          limits:
            cpu: "500m"
            memory: 1Gi
          requests:
            cpu: "500m"
            memory: 1Gi
        securityContext:
          capabilities:
            add:
              - IPC_LOCK
        lifecycle:
          preStop:
            exec:
              command: ["/bin/sh", "-c", "PID=$(pidof java) && kill $PID && while ps -p $PID > /dev/null; do sleep 1; done"]
        env:
          - name: MAX_HEAP_SIZE
            value: 512M
          - name: HEAP_NEWSIZE
            value: 100M
          - name: CASSANDRA_SEEDS
            value: "cassandra-0.cassandra.default.svc.cluster.local"
          - name: CASSANDRA_CLUSTER_NAME
            value: "K8Demo"
          - name: CASSANDRA_DC
            value: "DC1-K8Demo"
          - name: CASSANDRA_RACK
            value: "Rack1-K8Demo"
          - name: CASSANDRA_AUTO_BOOTSTRAP
            value: "false"
          - name: POD_IP
            valueFrom:
              fieldRef:
                fieldPath: status.podIP
          - name: POD_NAMESPACE
            valueFrom:
              fieldRef:
                fieldPath: metadata.namespace
        readinessProbe:
          exec:
            command:
            - /bin/bash
            - -c
            - /ready-probe.sh
          initialDelaySeconds: 40
          timeoutSeconds: 40
        # These volume mounts are persistent. They are like inline claims,
        # but not exactly because the names need to match exactly one of
        # the stateful pod volumes.
        volumeMounts:
        - name: cassandra-data
          mountPath: /var/lib/cassandra
  # These are converted to volume claims by the controller
  # and mounted at the paths mentioned above.
  volumeClaimTemplates:
  - metadata:
      name: cassandra-data
      annotations:
        volume.beta.kubernetes.io/storage-class: portworx-sc
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 1Gi
EOF

statefulset.apps/cassandra configured

Validate the cluster functionality

Use the kubectl get pvc command to verify that the PVCs are bound to your persistent volumes:

kubectl get pvc

NAME                         STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   VOLUMEATTRIBUTESCLASS   AGE
cassandra-data-cassandra-0   Bound    pvc-a9fbca67-713c-4442-xxxx-cafaaf5e20ad   1Gi        RWO            portworx-sc    <unset>                 4m41s
cassandra-data-cassandra-1   Bound    pvc-e6d39f88-0ea0-47a9-xxxx-c8f5a073d0de   1Gi        RWO            portworx-sc    <unset>                 3m22s
cassandra-data-cassandra-2   Bound    pvc-2cf36362-12e8-4527-xxxx-1b6a2391c073   1Gi        RWO            portworx-sc    <unset>                 2m21s

Verify that Kubernetes created the portworx-sc storage class:

kubectl get storageclass

NAME                 TYPE
portworx-sc          pxd.portworx.com

List your pod:

kubectl get pods

NAME          READY   STATUS    RESTARTS   AGE
cassandra-0   1/1     Running   0          8m47s
cassandra-1   1/1     Running   0          7m29s
cassandra-2   1/1     Running   0          6m28s

Use the pxctl volume list command to display the list of volumes in your cluster by running the following command on one of the pods that has Portworx installed:

pxctl volume list

ID			NAME						SIZE	HA	SHARED	ENCRYPTED	PROXY-VOLUME	IO_PRIORITY	STATUS				SNAP-ENABLED	
120416509069581339	pvc-2cf36362-12e8-4527-xxxx-1b6a2391c073	1 GiB	1	no	no		no		HIGH		up - attached on 10.13.xxx.x6	no
583995935441831735	pvc-a9fbca67-713c-4442-xxxx-cafaaf5e20ad	1 GiB	1	no	no		no		HIGH		up - attached on 10.13.xxx.xx8	no
1014207801779375780	pvc-e6d39f88-0ea0-47a9-xxxx-c8f5a073d0de	1 GiB	1	no	no		no		HIGH		up - attached on 10.13.xxx.xx0	no

Make a note of the ID of your volume. You'll need it in the next step.

To verify that your Portworx volumes has one replica, enter the pxctl volume inspect command, specifying the ID from the previous step. The following example command uses 120416509069581339:

pxctl volume inspect 120416509069581339

Volume          	 :  120416509069581339
Name            	 :  pvc-2cf36362-12e8-4527-xxxx-1b6a2391c073
Group            	 :  cassandra_vg
Size            	 :  1.0 GiB
Format          	 :  ext4
HA              	 :  1
IO Priority     	 :  HIGH
Creation time   	 :  Sep 23 07:29:14 UTC 2024
Shared          	 :  no
Status          	 :  up
State           	 :  Attached: xxxxxxxx-xxxx-xxxx-xxxx-7ee8b9b8c659 (10.13.xxx.x6)
Last Attached   	 :  Sep 23 07:29:16 UTC 2024
Device Path     	 :  /dev/pxd/pxd120416509069581xx9
Labels          	 :  app=cassandra,fg=true,group=cassandra_vg,namespace=default,priority_io=high,pvc=cassandra-data-cassandra-2,repl=1
Mount Options          	 :  discard
Reads           	 :  51
Reads MS        	 :  8
Bytes Read      	 :  413696
Writes          	 :  31
Writes MS       	 :  88
Bytes Written   	 :  16867328
IOs in progress 	 :  0
Bytes used      	 :  624 KiB
Replica sets on nodes:
 Set 0
   Node 		 : 10.13.xxx.x6
    Pool UUID	 : 99c52975-711a-47ed-xxxx-8a2eeb68615a
Replication Status	 :  Up
Volume consumers	 : 
 - Name           : cassandra-2 (f6a48a84-3da1-48d7-xxxx-18493effc8bf) (Pod)
   Namespace      : default
   Running on     : ip-10-13-xxx-x6.pwx.purestorage.com
   Controlled by  : cassandra (StatefulSet)

Note that this volume is up and the volume consumer is the cassandra-2 pod. If you want to have more replicas of volume, increase the replica count while creating the StorageClass portworx-sc. Please ensure you accordingly increase the worker nodes also and Portworx is installed on all the node to avoid preemption issues.

Show the list of your Pods and the hosts on which Kubernetes scheduled them:

kubectl get pods -l app=cassandra -o json | jq '.items[] | {"name": .metadata.name,"hostname": .spec.nodeName, "hostIP": .status.hostIP, "PodIP": .status.podIP}'

{
  "name": "cassandra-0",
  "hostname": "ip-10-13-xxx-xx8.pwx.purestorage.com",
  "hostIP": "10.xx.xxx.xx8",
  "PodIP": "10.xxx.xx.xx8"
}
{
  "name": "cassandra-1",
  "hostname": "ip-10-13-xxx-xx0.pwx.purestorage.com",
  "hostIP": "10.xx.xxx.xx0",
  "PodIP": "10.xxx.xx.xx0"
}
{
  "name": "cassandra-2",
  "hostname": "ip-10-13-xxx-x6.pwx.purestorage.com",
  "hostIP": "10.xx.xxx.xx6",
  "PodIP": "10.xx.xxx.x"
}

To open a shell session into one of your Pods, enter the following kubectl exec command, specifying your Pod name. This example opens the cassandra-0 Pod:
```
kubectl exec -it cassandra-0 -- bash
```

Use the nodetool status command to retrieve information about your Cassandra set up:

nodetool status

Datacenter: DC1-K8Demo
======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
--  Address        Load       Tokens       Owns (effective)  Host ID                               Rack
UN  10.2xx.xx.xx0  65.66 KiB  32           64.7%             315bd721-aadd-40a0-xxxx-10ac4e5ff668  Rack1-K8Demo
UN  10.2xx.xx.xx8  101.01 KiB  32           61.9%             2e686b0f-fd34-4456-xxxx-f664dbd36da6  Rack1-K8Demo
UN  10.2xx.xx.x    65.66 KiB  32           73.4%             6eccbd09-8641-43b3-xxxx-bac12293b1f9  Rack1-K8Demo

Terminate the shell session:
```
exit
```

Prerequisites​

Install Cassandra​

Validate the cluster functionality​

Related topics​

Prerequisites

Install Cassandra

Validate the cluster functionality

Related topics