OpenEBS storage class configuration reference for Lokomotive

Introduction

OpenEBS has many components, which can be grouped into the following categories.

Control plane components - Provisioner, API Server, volume exports, and volume sidecars.
Data plane components - Jiva and cStor.
Node disk manager - Discover, monitor, and manage the media attached to the Kubernetes node.
Integrations with cloud-native tools - Integrations are done with Prometheus, Grafana, Fluentd, and Jaeger.

According to OpenEBS, cStor is the recommended storage engine in OpenEBS.

This component configures the storage class and storage pool claim for OpenEBS the with cStor storage engine.

Prerequisites

Openebs operator installed and in running state.

Configuration

For a default component configuration, one need not specify a configuration file.

This component supports configuring multiple storage classes and providing disks to use for storage.

OpenEBS storage class component configuration example:

# openebs-storage-class.lokocfg
component "openebs-storage-class" {
  # Optional arguments
  storage-class "openebs-replica1" {
    replica_count  = 1
    reclaim_policy = "Delete"
  }

  storage-class "openebs-replica3" {
    replica_count  = 3
    default        = true
    reclaim_policy = "Retain"
    disks          = [
      "blockdevice-0565dd2d566cab012b7bc35e54874d9f",
      "blockdevice-17901367ccd9e1ead797a7e233de8cc8",
      "blockdevice-1f4315cb4acbb4b0dbf5202adcdb70d8"
    ]
  }
}

Attribute reference

Table of all the arguments accepted by the component.

Argument	Description	Default	Type	Required
`replica_count`	Defines the number of cStor volume replicas.	3	number	false
`default`	Indicates whether the storage class is default or not.	false	bool	false
`disks`	List of selected unclaimed BlockDevice CRs which are unmounted and do not contain a filesystem in each participating node.	-	list(string)	false
`reclaim_policy`	Persistent volumes created with this storage class will have this reclaim policy. This field decides what happens to the volume after a user deletes a PVC. Valid values: `Retain`, `Recycle` and `Delete`. Read more in the Kubernetes docs .	`Retain`	string	false

Applying

To apply the OpenEBS storage class component:

lokoctl component apply openebs-storage-class

Deleting

To destroy the component:

lokoctl component delete openebs-storage-class