Can kafka support block volume mount?

[tanberBro]

my kafka cluster is:

apiVersion: kafka.strimzi.io/v1beta2
kind: Kafka
metadata:
  name: my-cluster
spec:
  kafka:
    version: 3.5.1
    replicas: 3
    listeners:
      - name: plain
        port: 9092
        type: internal
        tls: false
      - name: tls
        port: 9093
        type: internal
        tls: true
    config:
      offsets.topic.replication.factor: 3
      transaction.state.log.replication.factor: 3
      transaction.state.log.min.isr: 2
      default.replication.factor: 3
      min.insync.replicas: 2
      inter.broker.protocol.version: "3.5"
    storage:
      type: jbod
      volumes:
      - id: 0
        type: persistent-claim
        size: 100Gi
        deleteClaim: false
  zookeeper:
    replicas: 3
    storage:
      type: persistent-claim
      size: 100Gi
      deleteClaim: false
  entityOperator:
    topicOperator: {}
    userOperator: {}

and when cluster is running,i see pvc is:

kubectl -n kafka-operator get pvc data-0-kafka-cluster-kafka-0 -oyaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  annotations:
    pv.kubernetes.io/bind-completed: "yes"
    pv.kubernetes.io/bound-by-controller: "yes"
    strimzi.io/delete-claim: "false"
    volume.beta.kubernetes.io/storage-provisioner: cluster.local/local-path-storage-local-path-provisioner
    volume.kubernetes.io/selected-node: nma07-304-d19-sev-r740-2u05
    volume.kubernetes.io/storage-provisioner: cluster.local/local-path-storage-local-path-provisioner
  creationTimestamp: "2023-12-04T05:59:26Z"
  finalizers:
  - kubernetes.io/pvc-protection
  labels:
    app.kubernetes.io/instance: kafka-cluster
    app.kubernetes.io/managed-by: strimzi-cluster-operator
    app.kubernetes.io/name: kafka
    app.kubernetes.io/part-of: strimzi-kafka-cluster
    strimzi.io/cluster: kafka-cluster
    strimzi.io/component-type: kafka
    strimzi.io/kind: Kafka
    strimzi.io/name: kafka-cluster-kafka
    strimzi.io/pool-name: kafka
  name: data-0-kafka-cluster-kafka-0
  namespace: kafka-operator
  resourceVersion: "55386919"
  uid: 12f4ca0d-1fa6-4824-9e62-04694bb083c8
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi
  storageClassName: local-path
  volumeMode: Filesystem
  volumeName: pvc-12f4ca0d-1fa6-4824-9e62-04694bb083c8
status:
  accessModes:
  - ReadWriteOnce
  capacity:
    storage: 5Gi
  phase: Bound

pvc.spec.volumeMode=Filesystem,
but I want kafka volume multiple disk,so what should I do?

[scholzj]

Apache Kafka requires a filesystem on its volumes. It cannot use raw block storage.

If you want to use multiple volumes in each Kafka broker, you can add them to the storage array in the Kafka custom resource. While that is useful in many situations to improve the overall capacity and in some cases performance, you probably do not want to use multiple 5Gi volumes but for example multiple 5Ti volumes as you are responsible for the balancing of the data between the disks.