OpenEBS¶

OpenEBS provides a local PV (Persistent Volume) provisioner for the cluster. It creates hostpath-backed persistent volumes that store data directly on the node's local filesystem -- no replication, no network overhead.

Architecture¶

flowchart LR
    PVC[PersistentVolumeClaim\nstorageClassName: openebs-hostpath] --> SC[StorageClass\nopenebs-hostpath]
    SC --> PROV[OpenEBS\nLocal PV Provisioner]
    PROV --> HP[Host Path\n/var/mnt/extra/openebs/local]

When to Use OpenEBS¶

OpenEBS local PVs are best suited for workloads that:

Manage their own replication -- databases like PostgreSQL (via CloudNativePG) or Redis that handle data replication at the application level
Need low-latency local I/O -- workloads where network storage overhead is unacceptable
Are tolerant of node affinity -- pods using local PVs are bound to the node where the volume was created

No replication

Data stored on OpenEBS local PVs exists only on a single node. If that node fails, the data is unavailable until the node recovers. Always ensure application-level replication or backups for critical data.

Configuration¶

Namespace¶

The OpenEBS namespace requires privileged Pod Security Standards since the provisioner needs host filesystem access:

namespace.yaml

apiVersion: v1
kind: Namespace
metadata:
  name: openebs
  labels:
    pod-security.kubernetes.io/enforce: privileged
    pod-security.kubernetes.io/audit: privileged
    pod-security.kubernetes.io/warn: privileged

Helm Chart¶

OpenEBS is deployed via the official Helm chart (v4.4.0) with only the local PV provisioner enabled:

values.yaml

localpv-provisioner:
  rbac:
    create: true
  localpv:
    image:
      registry: quay.io/
      repository: openebs/provisioner-localpv
    basePath: &hostPath /var/mnt/extra/openebs/local
  hostpathClass:
    enabled: true
    name: openebs-hostpath
    isDefaultClass: false
    basePath: *hostPath

# All other engines are disabled
openebs-crds:
  csi:
    volumeSnapshots:
      enabled: false
      keep: false
zfs-localpv:
  enabled: false
lvm-localpv:
  enabled: false
mayastor:
  enabled: false
engines:
  local:
    lvm:
      enabled: false
    zfs:
      enabled: false
  replicated:
    mayastor:
      enabled: false

Key settings:

Setting	Value	Purpose
`basePath`	`/var/mnt/extra/openebs/local`	Host directory where PVs are stored
`hostpathClass.name`	`openebs-hostpath`	StorageClass name for PVC requests
`hostpathClass.isDefaultClass`	`false`	Not the cluster default (Ceph is preferred)
`mayastor.enabled`	`false`	Replicated engine not needed (Rook Ceph fills this role)
`zfs-localpv.enabled`	`false`	No ZFS volumes on these nodes
`lvm-localpv.enabled`	`false`	No LVM volumes on these nodes

Minimal footprint

Only the localpv-provisioner component is active. All other OpenEBS engines (Mayastor, ZFS, LVM) are disabled to minimize resource usage and complexity.

Usage¶

To request a local PV, set the storageClassName to openebs-hostpath:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-database-data
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: openebs-hostpath
  resources:
    requests:
      storage: 20Gi

Node affinity

Once a pod is scheduled and a local PV is provisioned, the volume is tied to that specific node. The pod will always be scheduled on the same node as its volume. If the node is unavailable, the pod cannot start elsewhere unless the PV is manually recreated.

Comparison with Rook Ceph¶

Feature	OpenEBS (Local PV)	Rook Ceph
Replication	None	3-way across nodes
Latency	Lowest (local disk)	Higher (network + replication)
Node failure tolerance	No (data on single node)	Yes (data survives 1 node loss)
Pod scheduling	Pinned to volume node	Can reschedule freely
Best for	Databases with app-level replication	General workloads
StorageClass	`openebs-hostpath`	`ceph-block`