Ceph Object - cephobject

Ceph (opens in a new tab) is an open-source storage platform that stores its data in a storage cluster based on RADOS. It is highly scalable and, as a distributed system without a single point of failure, very reliable.

Tip
If you want to quickly set up a basic Ceph cluster, check out MicroCeph (opens in a new tab).

Ceph provides different components for block storage and for file systems.

Ceph Object Gateway (opens in a new tab) is an object storage interface built on top of librados (opens in a new tab) to provide applications with a RESTful gateway to Ceph Storage Clusters (opens in a new tab). It provides object storage functionality with an interface that is compatible with a large subset of the Amazon S3 RESTful API.

Terminology

Ceph uses the term object for the data that it stores. The daemon that is responsible for storing and managing data is the Ceph OSD. Ceph's storage is divided into pools, which are logical partitions for storing objects. They are also referred to as data pools, storage pools or OSD pools.

A Ceph Object Gateway consists of several OSD pools and one or more Ceph Object Gateway daemon (radosgw) processes that provide object gateway functionality.

cephobject driver in LXD

Note
The cephobject driver can only be used for buckets.
For storage volumes, use the Ceph or CephFS drivers.

Unlike other storage drivers, this driver does not set up the storage system but assumes that you already have a Ceph cluster installed.

You must set up a radosgw environment beforehand and ensure that its HTTP/HTTPS endpoint URL is reachable from the LXD server or servers. See Manual Deployment (opens in a new tab) for information on how to set up a Ceph cluster and Ceph Object Gateway (opens in a new tab) on how to set up a radosgw environment.

The radosgw URL can be specified at pool creation time using the cephobject.radosgw.endpoint option.

LXD uses the radosgw-admin command to manage buckets. So this command must be available and operational on the LXD servers.

This driver also behaves differently than other drivers in that it provides remote storage. As a result and depending on the internal network, storage access might be a bit slower than for local storage. On the other hand, using remote storage has big advantages in a cluster setup, because all cluster members have access to the same storage pools with the exact same contents, without the need to synchronize storage pools.

LXD assumes that it has full control over the OSD storage pool. Therefore, you should never maintain any file system entities that are not owned by LXD in a LXD OSD storage pool, because LXD might delete them.

Configuration options

The following configuration options are available for storage pools that use the cephobject driver and for storage buckets in these pools.

Storage pool configuration

cephobject.bucket.name_prefix

Prefix to add to bucket names in Ceph

• Key: cephobject.bucket.name_prefix
• Type: string
• Scope: global

cephobject.cluster_name

The Ceph cluster to use

• Key: cephobject.cluster_name
• Type: string
• Scope: global

cephobject.radosgw.endpoint

URL of the radosgw gateway process

• Key: cephobject.radosgw.endpoint
• Type: string
• Scope: global

cephobject.radosgw.endpoint_cert_file

TLS client certificate to use for endpoint communication

• Key: cephobject.radosgw.endpoint_cert_file
• Type: string
• Scope: global

Specify the path to the file that contains the TLS client certificate.

cephobject.user.name

The Ceph user to use

• Key: cephobject.user.name
• Type: string
• Default: admin
• Scope: global

volatile.pool.pristine

Whether the radosgw lxd-admin user existed at creation time

• Key: volatile.pool.pristine
• Type: string
• Default: true
• Scope: global

Storage bucket configuration

size

Quota of the storage bucket

• Key: size
• Type: string
• Scope: local