xnbd-register(1) Restore xNBD sessions upon boot


xnbd-register [--start] [--stop] [--restart] [--status] [--quiet]


With the xmbd-register command one can restore xnbd-server and xnbd-client sessions based on a configuration file. This is useful to start both, client or server upon boot.

To achieve this, xmbd-register reads a semi-structured configuration file located in /etc/xnbd.conf. See below for format hints.


The following options are supported:

Start devices configured in the configuration files. If the configuration files describes volumes, xnbd-register will try to establish a client connection to the configured server instance.
Alternatively, xnbd-register will start sharing configured volumes by starting an xnbd-wrapper super server.
Retrieve server status from a running xnbd-wrapper command, if applicable.
Analogous to the start option, the stop argument will stop all xnbd connection, being client or server instances.
Restart all xnbd instances, being client or server


xnbd-register will read its defaults from /etc/xnbd.conf. This is a semi-structured configuration file, describing client and server connections that are supposed to be restored upon start of the system.

The syntax of the file is a JSON data structure, allowing comments starting with a hash key ("#"). Two types of objects are recognized: xnbd volumes and a server instance. xnbd volumes are indexed by the supposed devices name. This is, to restore /dev/nbd0 an object named "nbd0 must be configured. Valid arguments are host, name and port. So, for example, this is to configure /dev/nbd0 connecting to localhost on port 8520. If present, identify the shared device by the configured logical name:

"nbd0": { 
"host": "", 
"port": 8520, 
"name": "name" 

Similarly, a server instance configures an xnbd-wrapper. Valid options are:

Specifies the listening address
Specifies the listening port
Specifies the listening socket for the control channels
Specifies the log path where logging output is being redirected to
A list of volumes which are exported

"server": { 
"address": "", 
"port": 8520, 
"socket": "/var/run/xnbd.ctl", 
"logpath": "/tmp/xnbd.log", 
"volumes": [ "/dev/volume", "/dev/sdb1", "/var/lib/image.file" ] 


xnbd-register was written by Arno Toell ([email protected]) for the Debian GNU/Linux system. Report bugs to the Debian bug tracking system on http://bugs.debian.org

This manual page was written by Arno Toell ([email protected]) for the Debian GNU/Linux system (but may be used by others). Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License, version 2, as published by the Free Software Foundation.