Storage configuration

Atmosphere uses a unified storage configuration variable atmosphere_storage that serves as the single source of truth for all storage backends across OpenStack services. This eliminates the need to configure storage settings in multiple places.

Overview

The atmosphere_storage variable organizes storage by purpose:

images

Image storage for Glance. Supports multiple backends.

volumes

Block storage for Cinder. Supports multiple backends.

backup

Backup storage for Cinder backup.

ephemeral

Ephemeral disk storage for Nova and libvirt.

The system automatically derives per-service Helm values from this single variable for Cinder, Glance, Nova, libvirt, and Ceph Provisioners.

Default configuration

By default, Atmosphere configures image and volume storage to use the integrated Ceph cluster, with local (qcow2) ephemeral disks for Nova. The atmosphere_storage variable defaults to an empty dictionary ({}), and the built-in defaults provide sensible starting values.

You can override any part of the configuration by setting atmosphere_storage in your inventory. Your overrides merge on top of the built-in defaults using a recursive merge, so you only need to specify the parts you want to change.

The built-in defaults are equivalent to:

images:
  default: rbd1
  backends:
    rbd1:
      type: rbd
      pool: glance.images
      replication: 3
      crush_rule: replicated_rule
      chunk_size: 8
      user: glance
volumes:
  default: rbd1
  backends:
    rbd1:
      type: rbd
      pool: cinder.volumes
      replication: 3
      crush_rule: replicated_rule
      user: cinder
      secret_uuid: 457eb676-33da-42ec-9a8c-9293d545c337
backup:
  type: rbd
  pool: cinder.backups
  replication: 3
  crush_rule: replicated_rule
  user: cinderbackup
ephemeral:
  type: local

The integrated Ceph cluster works without additional configuration.

Enabling RBD ephemeral storage

To use Ceph RBD for Nova ephemeral disks instead of local storage, set the ephemeral section in your atmosphere_storage override:

atmosphere_storage:
  ephemeral:
    type: rbd
    pool: vms
    replication: 3
    crush_rule: replicated_rule
    user: cinder
    secret_uuid: 457eb676-33da-42ec-9a8c-9293d545c337

Supported backend types

Ceph RBD (rbd)

Standard replicated Ceph RBD backend. Used for images, volumes, backups, and ephemeral storage.

type: rbd
pool: <pool_name>
replication: 3
crush_rule: replicated_rule
user: <username>
secret_uuid: <uuid>       # required for volumes and ephemeral

Ceph RBD erasure-coded (rbd-ec)

Erasure-coded Ceph RBD backend for improved storage efficiency. Only supported for volume backends. EC pools provide better storage utilization compared to replicated pools, at the cost of slightly higher CPU overhead.

EC pools require two components:

1. A metadata pool (replicated) that stores metadata

2. A data pool (EC) that stores the actual volume data

type: rbd-ec
pool: cinder.volumes.ec
erasure_coded:
  k: 4                     # data chunks
  m: 2                     # coding (parity) chunks
  failure_domain: host
  device_class: hdd        # optional
metadata_replication: 3
user: cinder-ec       # must be unique per EC backend
secret_uuid: <unique-uuid>

The EC pool configuration parameters are:

k

Number of data chunks. Higher values provide better storage efficiency.

m

Number of coding (parity) chunks. Higher values provide better fault tolerance.

device_class

Target specific device types, for example hdd, ssd, or nvme.

failure_domain

Failure domain for data placement, for example host, rack, or room.

Warning

Each erasure-coded backend requires a dedicated user and a unique secret_uuid. Generate new UUID’s with uuidgen.

Dell PowerStore (powerstore)

Warning

Make sure that you set up the hosts inside of your storage array. They must not be inside a host group, or individual attachments won’t work.

type: powerstore
address: <management_ip_or_hostname>
username: <username>
password: <password>
protocol: iscsi    # or fc

Pure storage (pure)

Pure Storage FlashArray integration. When using the NVMe protocol, you can optionally set transport to roce or tcp.

For additional options, see the Cinder Pure Storage documentation.

type: pure
protocol: iscsi    # or fc, nvme
address: <management_ip_or_hostname>
api_token: <token>
transport: roce    # optional, only for nvme protocol

StorPool (storpool)

StorPool distributed storage backend. The system configures network settings and file system mounts automatically.

type: storpool
template: hybrid-2ssd

Cinder (cinder)

Cinder-backed Glance store. Only used for image backends.

type: cinder

Examples

Adding an erasure-coded volume backend

To add an EC pool alongside the default replicated backend, add a new entry under atmosphere_storage.volumes.backends:

atmosphere_storage:
  volumes:
    backends:
      rbd_ec:
        type: rbd-ec
        pool: cinder.volumes.ec
        erasure_coded:
          k: 4
          m: 2
          failure_domain: host
        metadata_replication: 3
        user: cinder-ec
        secret_uuid: 808c5658-7c46-4818-8f26-82a217e3a57a

The system automatically configures all required services: Cinder backend configuration, Ceph pool creation, libvirt secret registration, and Ceph client data pool routing.

Using Dell PowerStore

atmosphere_storage:
  volumes:
    default: powerstore
    backends:
      powerstore:
        type: powerstore
        address: 10.0.0.1
        username: admin
        password: secret
        protocol: iscsi
  backup:
    type: none
  ephemeral:
    type: local

Glance with multiple backends

atmosphere_storage:
  images:
    default: rbd1
    backends:
      rbd1:
        type: rbd
        pool: glance.images
        replication: 3
        user: glance
      cinder_store:
        type: cinder

Advanced overrides

The atmosphere_storage variable generates base Helm values. You can still use per-service *_helm_values variables (such as cinder_helm_values or glance_helm_values) to override specific settings. The per-service overrides always take precedence.

Migrating from atmosphere_ceph_enabled

The atmosphere_ceph_enabled variable is no longer supported. Storage configuration now uses the unified atmosphere_storage variable. If your inventory sets atmosphere_ceph_enabled, remove it and configure atmosphere_storage instead.

If you previously set atmosphere_ceph_enabled: true

No action beyond removing the variable is necessary. The built-in defaults already configure Ceph RBD for images and volumes, which matches the previous behavior.

# Remove this from your inventory:
# atmosphere_ceph_enabled: true

If you previously set atmosphere_ceph_enabled: false

Remove the variable and configure atmosphere_storage to match your environment. For example, if you use Dell PowerStore for volumes and local ephemeral storage:

# Remove this from your inventory:
# atmosphere_ceph_enabled: false

# Add this instead:
atmosphere_storage:
  images:
    default: cinder_store
    backends:
      cinder_store:
        type: cinder
  volumes:
    default: powerstore
    backends:
      powerstore:
        type: powerstore
        address: 10.0.0.1
        username: admin
        password: secret
        protocol: iscsi
  backup:
    type: none
  ephemeral:
    type: local