xnbd-register1

Usage

Overview

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.

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 server instance.

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

--status

Retrieve server 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 server instances.

--restart

Restart all xnbd instances, being client or server

Configuration file

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": "127.0.0.1", 
"port": 8520, 
"name": "name" 
} 

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

"server": { 
"address": "127.0.0.1", 
"port": 8520, 
"socket": "/var/run/xnbd.ctl", 
"logpath": "/tmp/xnbd.log", 
"volumes": [ "/dev/volume", "/dev/sdb1", "/var/lib/image.file" ] 
}