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Local Disk Manager

LDM architecture

At present, the LDM project is still in the alpha stage.

Concepts

LocalDisk (LD): LDM abstracts disk resources into objects in kubernetes. An LD resource object represents the disk resources on the host.

LocalDiskClaim (LDC): This is a way to use disks. A user can add the disk description to select a disk for use.

Note

At present, LDC supports the following options to describe disk:

  • NodeName
  • Capacity
  • DiskType (such as HDD/SSD/NVMe)

Usage

  1. Get the LocalDisk information.

    kubectl get localdisk
NAME               NODEMATCH        PHASE
10-6-118-11-sda    10-6-118-11      Available
10-6-118-11-sdb    10-6-118-11      Available

    Get locally discovered disk resource information with three columns displayed.

    • NAME: represents how this disk is displayed in the cluster resources.
    • NODEMATCH: indicates which host this disk is on.
    • PHASE: represents the current state of the disk.

    Use kubectl get localdisk <name> -o yaml to view more information about disks.

  2. Claim available disks.

    1. Apply a LocalDiskClaim.

      cat << EOF | kubectl apply -f -
apiVersion: hwameistor.io/v1alpha1
kind: LocalDiskClaim
metadata:
  name: <localDiskClaimName>
spec:
  description:
    # e.g. HDD,SSD,NVMe
    diskType: <diskType>
  # the node where disks attached
  nodeName: <nodeName>
  # the owner of the allocated disks e.g. local-storage,local-disk-manager
  owner: <ownerName>
EOF

      Allocate available disks by issuing a disk usage request. In the request description, you can add more requirements about the disk, such as disk type and capacity.

    2. Get the LocalDiskClaim information.

      kubectl get localdiskclaim <name>

    3. Once the LDC is processed successfully, it will be cleanup by the system automatically. The result will be recorded in the LocalStorageNode if the owner is local-storage.

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