Creating manual BlockDevice

BlockDevices are the consumable units of storage in the OpenEBS storage solution. Currently, NDM supports the discovery and management of only a complete disk.

However, users can create BlockDevices manually to support custom partitions/lvms, etc., which are not detected by NDM. To create a manual BlockDevice, follow the steps below:

1. Download the sample block device custom resource YAML file.
   

   ```
   wget
   https://raw.githubusercontent.com/openebs/node-disk-manager/master/deploy/crds/openebs_v1alpha1_blockdevice_cr.yaml
   ```

2. Edit the file and fill in the details of the blockdevice. Fields marked with optional are not mandatory and can be removed. All other fields are required and information provided will be used while claiming.
   

   ```
   apiVersion: openebs.io/v1alpha1
   kind: BlockDevice
   metadata:
     name: example-blockdevice
     labels:
       kubernetes.io/hostname: <host name of the node in which disk/blockdevice is attached> # like gke-openebs-user-default-pool-044afcb8-bmc0
       ndm.io/managed: "false" # for manual disk creation put false
       ndm.io/blockdevice-type: blockdevice
   status:
     claimState: Unclaimed
     state: Active
   spec:
     capacity:
          storage: <total capacity in bytes> #like 53687091200
     details:
       firmwareRevision: <firmware revision> #optional
       model: <model name of blockdevice> # like PersistentDisk, optional
       serial: <serial no of disk> # like google-disk-2, optional
       compliance: <compliance of disk> #like "SPC-4", optional
       vendor: <vendor of disk> #like Google, optional
     devlinks:
     - kind: by-id
       links:
       - <link1> # like /dev/disk/by-id/scsi-0Google_PersistentDisk_disk-2
       - <link2> # like /dev/disk/by-id/google-disk-2
     - kind: by-path
       links:
       - <link1> # like /dev/disk/by-path/virtio-pci-0000:00:03.0-scsi-0:0:2:0
     nodeAttributes:
       nodeName: <node name> # output of `kubectl get nodes` can be used
     path: <devpath> # like /dev/sdb
   ```

3. Apply the YAML file.

```
kubectl apply -f openebs_v1alpha1_blockdevice_cr.yaml 
```

The BlockDevice CR will be created and is then used by NDM Operator for claiming, but it won’t be managed by NDM Daemon for any changes that happen on the device. However, all the Claim/Unclaim operations and cleanup operations will be performed on this BlockDevice.

Please provide your valuable feedback & comments below and let me know what I can cover in my next blog.

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