rbd-nbd – map rbd images to nbd device¶

Synopsis¶

rbd-nbd [-c conf] [–read-only] [–device nbd device] [–nbds_max limit] [–max_part limit] [–exclusive] [–encryption-format format] [–encryption-passphrase-file passphrase-file] [–io-timeout seconds] [–reattach-timeout seconds] map image-spec | snap-spec
rbd-nbd unmap nbd device | image-spec | snap-spec
rbd-nbd list-mapped
rbd-nbd attach –device nbd device image-spec | snap-spec
rbd-nbd detach nbd device | image-spec | snap-spec

Description¶

rbd-nbd is a client for RADOS block device (rbd) images like rbd kernel module. It will map a rbd image to a nbd (Network Block Device) device, allowing access it as regular local block device.

Options¶

-c ceph.conf¶: Use ceph.conf configuration file instead of the default /etc/ceph/ceph.conf to determine monitor addresses during startup.

--read-only¶: Map read-only.

--nbds_max *limit*¶: Override the parameter nbds_max of NBD kernel module when modprobe, used to limit the count of nbd device.

--max_part *limit*¶: Override for module param max_part.

--exclusive¶: Forbid writes by other clients.

--encryption-format¶: Image encryption format. Possible values: luks1, luks2

--encryption-passphrase-file¶: Path of file containing a passphrase for unlocking image encryption.

--io-timeout *seconds*¶: Override device timeout. Linux kernel will default to a 30 second request timeout. Allow the user to optionally specify an alternate timeout.

--reattach-timeout *seconds*¶: Specify timeout for the kernel to wait for a new rbd-nbd process is attached after the old process is detached. The default is 30 second.

Image and snap specs¶

image-spec is [pool-name]/image-name

snap-spec is [pool-name]/image-name@snap-name

The default for pool-name is “rbd”. If an image name contains a slash character (‘/’), pool-name is required.

Availability¶

rbd-nbd is part of Ceph, a massively scalable, open-source, distributed storage system. Please refer to the Ceph documentation at http://ceph.com/docs for more information.