Storage pool type: `rbd`

Ceph is a distributed object store and file system designed to provide excellent performance, reliability and scalability. RADOS block devices implement a feature rich block level storage, and you get the following advantages:

- thin provisioning

- resizable volumes

- distributed and redundant (striped over multiple OSDs)

- full snapshot and clone capabilities

- self healing

- no single point of failure

- scalable to the exabyte level

- kernel and user space implementation available

| For smaller deployments, it is also possible to run Ceph services directly on your Proxmox VE nodes. Recent hardware has plenty of CPU power and RAM, so running storage services and VMs on same node is possible.

## Configuration

This backend supports the common storage properties `nodes`, `disable`, `content`, and the following `rbd` specific properties:

monhost

  List of monitor daemon IPs. Optional, only needed if Ceph is not running on the Proxmox VE cluster.

pool

  Ceph pool name.

username

  RBD user ID. Optional, only needed if Ceph is not running on the Proxmox VE cluster. Note that only the user ID should be used. The "client." type prefix must be left out.

krbd

  Enforce access to rados block devices through the krbd kernel module. Optional.

| Containers will use `krbd` independent of the option value.

Configuration Example for a external Ceph cluster (`/etc/pve/storage.cfg`)

    rbd: ceph-external
            monhost 10.1.1.20 10.1.1.21 10.1.1.22
            pool ceph-external
            content images
            username admin

| You can use the `rbd` utility to do low-level management tasks.

## Authentication

| If Ceph is installed locally on the Proxmox VE cluster, the following is done automatically when adding the storage.

If you use `cephx` authentication, which is enabled by default, you need to provide the keyring from the external Ceph cluster.

To configure the storage via the CLI, you first need to make the file containing the keyring available. One way is to copy the file from the external Ceph cluster directly to one of the Proxmox VE nodes. The following example will copy it to the `/root` directory of the node on which we run it:

    # scp <external cephserver>:/etc/ceph/ceph.client.admin.keyring /root/rbd.keyring

Then use the `pvesm` CLI tool to configure the external RBD storage, use the `--keyring` parameter, which needs to be a path to the keyring file that you copied. For example:

    # pvesm add rbd <name> --monhost "10.1.1.20 10.1.1.21 10.1.1.22" --content images --keyring /root/rbd.keyring

When configuring an external RBD storage via the GUI, you can copy and paste the keyring into the appropriate field.

The keyring will be stored at

    # /etc/pve/priv/ceph/<STORAGE_ID>.keyring

| Creating a keyring with only the needed capabilities is recommend when connecting to an external cluster. For further information on Ceph user management, see the Ceph docs. [Ceph User Management]

## Ceph client configuration (optional)

Connecting to an external Ceph storage doesn’t always allow setting client-specific options in the config DB on the external cluster. You can add a `ceph.conf` beside the Ceph keyring to change the Ceph client configuration for the storage.

The ceph.conf needs to have the same name as the storage.

    # /etc/pve/priv/ceph/<STORAGE_ID>.conf

See the RBD configuration reference
[RBD configuration reference https://docs.ceph.com/en/quincy/rbd/rbd-config-ref/]
for possible settings.

| Do not change these settings lightly. Proxmox VE is merging the <STORAGE_ID>.conf with the storage configuration.

## Storage Features

The `rbd` backend is a block level storage, and implements full snapshot and clone functionality.

Table 1. Storage features for backend `rbd`
Content types | Image formats | Shared | Snapshots | Clones
--- | --- | --- | --- | ---
`images rootdir` | `raw` | yes | yes | yes

## See Also

- Storage