Enable LVM ephemeral storage

TechPreview

Note

Consider this section as part of Deploy an OpenStack cluster.

This section instructs you on how to configure LVM as back end for the VM disks and ephemeral storage.

You can use flexible size units throughout bare metal host profiles. For example, you can now use either sizeGiB: 0.1 or size: 100Mi when specifying a device size.

Mirantis recommends using only one parameter name type and units throughout the configuration files. If both sizeGiB and size are used, sizeGiB is ignored during deployment and the suffix is adjusted accordingly. For example, 1.5Gi will be serialized as 1536Mi. The size without units is counted in bytes. For example, size: 120 means 120 bytes.

Warning

All data will be wiped during cluster deployment on devices defined directly or indirectly in the fileSystems list of BareMetalHostProfile. For example:

  • A raw device partition with a file system on it

  • A device partition in a volume group with a logical volume that has a file system on it

  • An mdadm RAID device with a file system on it

  • An LVM RAID device with a file system on it

The wipe field is always considered true for these devices. The false value is ignored.

Therefore, to prevent data loss, move the necessary data from these file systems to another server beforehand, if required.

Warning

Usage of more than one nonvolatile memory express (NVMe) drive per node may cause update issues and is therefore not supported.

To enable LVM ephemeral storage:

  1. In BareMetalHostProfile in the spec:volumeGroups section, add the following configuration for the OpenStack compute nodes:

    spec:
  devices:
    - device:
        byName: /dev/nvme0n1
        minSize: 30Gi
        wipe: true
      partitions:
        - name: lvm_nova_vol
          size: 0
          wipe: true
  volumeGroups:
    - devices:
      - partition: lvm_nova_vol
      name: nova-vol
  logicalVolumes:
    - name: nova-fake
      vg: nova-vol
      size: 100Mi
  fileSystems:
    - fileSystem: ext4
      logicalVolume: nova-fake
      mountPoint: /nova-fake

    Note

    Due to a limitation, it is not possible to create volume groups without logical volumes and formatted partitions. Therefore, set the logicalVolumes:name, fileSystems:logicalVolume, and fileSystems:mountPoint parameters to nova-fake.

    For details about BareMetalHostProfile, see Mirantis Container Cloud Operations Guide: Create a custom bare metal host profile.

  2. Configure the OpenStackDeployment CR to deploy OpenStack with LVM ephemeral storage. For example:

    spec:
  features:
    nova:
      images:
        backend: lvm
        lvm:
          volume_group: "nova-vol"

  3. Optional. Enable encryption for the LVM ephemeral storage by adding the following metadata in the OpenStackDeployment CR:

    spec:
  features:
    nova:
      images:
        encryption:
          enabled: true
          cipher: "aes-xts-plain64"
          key_size: 256

    Caution

    Both live and cold migrations are not supported for such instances.