========================== Kernel Module Operations

.. index:: Ceph Block Device; kernel module

.. important:: To use kernel module operations, you must have a running Ceph cluster.

Get a List of Images

To mount a block device image, first return a list of the images. ::

rbd list

Map a Block Device

Use rbd to map an image name to a kernel module. You must specify the image name, the pool name, and the user name. rbd will load RBD kernel module on your behalf if it's not already loaded. ::

sudo rbd device map {pool-name}/{image-name} --id {user-name}

For example::

sudo rbd device map rbd/myimage --id admin

If you use cephx_ authentication, you must also specify a secret. It may come from a keyring or a file containing the secret. ::

sudo rbd device map rbd/myimage --id admin --keyring /path/to/keyring sudo rbd device map rbd/myimage --id admin --keyfile /path/to/file

Show Mapped Block Devices

To show block device images mapped to kernel modules with the rbd, specify device list arguments. ::

rbd device list

Unmapping a Block Device

To unmap a block device image with the rbd command, specify the device unmap arguments and the device name (i.e., by convention the same as the block device image name). ::

sudo rbd device unmap /dev/rbd/{poolname}/{imagename}

For example::

sudo rbd device unmap /dev/rbd/rbd/foo

.. _cephx: ../../rados/operations/user-management/