# OpenEBS — Leading Open Source Container-Attached Storage

> OpenEBS is a CNCF storage project that provides dynamic persistent volumes for Kubernetes using multiple storage engines — Local PV, Replicated Mayastor, cStor, and Jiva — chosen per workload.

## Install

Save in your project root:

# OpenEBS — Leading Open Source Container-Attached Storage

## Quick Use
```bash
# Install the OpenEBS operator (includes Local PV and Mayastor controllers)
helm repo add openebs https://openebs.github.io/openebs
helm upgrade --install openebs openebs/openebs 
  -n openebs --create-namespace

# Verify default StorageClasses
kubectl get sc

# Use Local PV Hostpath for a stateful workload
kubectl apply -f - <<YAML
apiVersion: v1
kind: PersistentVolumeClaim
metadata: {name: data}
spec:
  accessModes: [ReadWriteOnce]
  storageClassName: openebs-hostpath
  resources: {requests: {storage: 10Gi}}
YAML
```

## Introduction
OpenEBS pioneered the Container-Attached Storage (CAS) pattern: each volume is a small, user-space storage controller that runs next to the workload, instead of a monolithic cluster-wide storage daemon. That keeps the blast radius tight, makes upgrades painless, and matches Kubernetes'' Pod-per-concern ethos.

## What OpenEBS Does
- Provisions PersistentVolumes via Kubernetes CSI drivers across multiple engines.
- Local PV (Hostpath, Device, LVM, ZFS) for high-performance node-local storage.
- Mayastor for NVMe-over-Fabric replicated block storage with µs-level latency.
- cStor / Jiva for replicated iSCSI-backed volumes with snapshots and clones.
- Exposes metrics, snapshots, clones, and volume expansion through standard Kubernetes APIs.

## Architecture Overview
OpenEBS is deployed as a set of operators and per-engine controllers. For Local PV it is effectively a thin CSI shim around Hostpath, LVM, or ZFS on each node. For Mayastor, a user-space data plane (MIO + SPDK) runs as DaemonSets connecting NVMe devices to replicated “nexus” volumes. Control lives in Kubernetes CRDs (`StoragePoolClaim`, `CStorVolume`, `MayastorPool`) so GitOps works end-to-end.

## Self-Hosting & Configuration
- Minimum: a few nodes with spare block devices or a directory for Hostpath volumes.
- Enable only the engines you need by setting Helm values (`localpv-provisioner.enabled`, `mayastor.enabled`, …).
- Label nodes with `openebs.io/storage-pool=<pool>` to control where volumes land.
- Use `openebs-zfspv` or `openebs-lvmlocalpv` for snapshot- and clone-capable local storage.
- Integrate with Prometheus: a `ServiceMonitor` for each engine exposes IO, latency, and rebuild metrics.

## Key Features
- Engine choice per workload — ultra-fast local NVMe for Kafka, replicated block for Postgres, Hostpath for logs.
- CSI-native: snapshots, clones, volume resize, topology-aware scheduling.
- Non-disruptive upgrades of the storage control plane.
- Mayastor delivers NVMe-oF performance with optional 3-way replication.
- Strong CNCF credentials (Sandbox → Incubating) and an active commercial ecosystem (MayaData, DataCore).

## Comparison with Similar Tools
- **Rook-Ceph** — full POSIX + object + block; heavier cluster dependency. OpenEBS is simpler and per-volume.
- **Longhorn** — single-engine replicated block storage with great UI; OpenEBS offers more engine options.
- **Portworx** — commercial and polished; OpenEBS is free and avoids licensing negotiations.
- **TopoLVM** — pure Local PV LVM; OpenEBS Local PV LVM gives you the same plus a broader ecosystem.
- **Piraeus (LINSTOR / DRBD)** — great replicated block; OpenEBS adds local engines for workloads that don''t need replication.

## FAQ
**Q: Which engine should I pick?**
A: Local PV Hostpath for lab work, LVM/ZFS Local PV for production single-node performance, Mayastor for replicated NVMe.

**Q: Does OpenEBS work on ARM / Raspberry Pi clusters?**
A: Yes — Local PV engines run everywhere; Mayastor requires modern x86_64 with HugePages enabled.

**Q: Can I use it alongside cloud block storage (EBS, PD)?**
A: Absolutely — many teams use EBS for databases and OpenEBS Local PV for caches and ephemeral state.

**Q: How mature is Mayastor?**
A: Production-ready since 2.0; widely used for Kafka, Cassandra, and Postgres at scale.

## Sources
- https://github.com/openebs/openebs
- https://openebs.io/docs


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Source: https://tokrepo.com/en/workflows/3ba4ce73-38cf-11f1-9bc6-00163e2b0d79
Author: AI Open Source