---
name: "xnbd-register"
section: "8"
platform: "linux"
package: "xnbd-common"
version: "0.3.0-3"
release: "Debian 10 (Buster)"
platforms: ["linux"]
url: "https://new.carta.tech/xnbd-register/8"
---

# xnbd-register(8)

Restore xNBD sessions upon boot

## NAME

xnbd-register - Restore xNBD sessions upon boot

## SYNOPSIS

**xnbd-register** \[*OPTIONS*\] --start

**xnbd-register** \[*OPTIONS*\] --stop

**xnbd-register** \[*OPTIONS*\] --restart

**xnbd-register** \[*OPTIONS*\] --status

## DESCRIPTION

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

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

## OPTIONS

The following options are supported:

- **--start**

  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 wrapper instance.

  Alternatively, xnbd-register will start sharing configured volumes by starting an xnbd-wrapper super server.

- **--status**

  Retrieve wrapper status from a running xnbd-wrapper command, if applicable.

- **--stop**

  Analogous to the start option, the stop argument will stop all xnbd connection, being client or wrapper instances.

- **--restart**

  Restart all xnbd instances, being client or wrapper

- **--config** *FILE*

  Config file to use. Defaults to /etc/xnbd.conf.

- **--quiet**

  Do not produce verbose output

## CONFIGURATION FILE

xnbd-register will read its defaults from /etc/xnbd.conf. This is a semi-structured configuration file, describing client and wrapper 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 wrapper 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": "127.0.0.1",
    "port": 8520,
    "name": "name"
}
```

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

**address**

Specifies the listening address

**port**

Specifies the listening port

**socket**

Specifies the listening socket for the control channels

**logpath**

Specifies the log path where logging output is being redirected to

**volumes**

A mapping of volumes which are exported. Mapping keys are export names, mapping values are disk image paths.

```
"wrapper": {
    "address": "127.0.0.1",
    "port": 8520,
    "socket": "/var/run/xnbd.ctl",
    "logpath": "/var/log/xnbd.log",
    "volumes": {
        "one": "/dev/volume",
        "two": "/dev/sdb1",
        "three": "/var/lib/image.file",
    }
}
```

## SEE ALSO

[xnbd-wrapper(8)](/xnbd-wrapper/8.md), [xnbd-client(1)](/xnbd-client/1.md)

## AUTHOR

xnbd-register was written by Arno Toell (arno@debian.org) for the Debian GNU/Linux system.

This manual page was written by Arno Toell (arno@debian.org) 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.