xnbd-wrapper (8)

xnbd-wrapper [ --imgfile IMAGE [--imgfile IMAGE ...] ] [--laddr ADDRESS] [--lport PORT] [--socket PATH] [--xnbd-server PATH] [--daemonize] [--logpath PATH] [--max-buf-size NUMBER] [--max-queue-size NUMBER]

xnbd-wrapper is a super-server for xnbd-server. Its purpose is to manage multiple exported images at once. A client may connect to this super-server and it will be indirected to the actual xnbd-server providing the requested resource.

xnbd-wrapper comes handy if you want to export multiple files (or block devices) on a single host. Instead of starting multiple xnbd-server instances and remember the exported port for each, you can use xnbd-wrapper to looks up the requested image file name and map it automatically to the corresponding xnbd-server.

The following options are supported:

--daemonize

Go into background as soon as the xnbd-server is started up

--imgfile IMAGE

Export the image file IMAGE through xnbd-wrapper, with IMAGE being a block device or a file name of an image file.

xnbd-wrapper will export the file name accessible through this name to clients, which may connect to the server by providing this name

This option can be specified multiple times. In this case, xnbd-wrapper will export all IMAGE files at once. Alternatively, this argument can be omitted and images may be (un-)exported ar runtime with xnbd-wrapper-ctl.

--laddr ADDRESS

The address, where this wrapper shall listen for incoming connections. You can specify any resolvable hostname or IP address, being in IPv4 or IPv6 notation.

--logpath FILE

Log informational messages to file FILE rather than stderr/syslog.

--syslog

Log informational messages to syslog.

--lport PORT

Accept incoming connections on the given PORT. A valid port is any number between 1 and 65536. You may not use the same listeing port more than once per system. If this argument is not given, xNBD will listen on port 8520 by default.

(--port PORT)

Deprecated, please use --lport instead. This option might be removed in future releases.

--socket PATH

The xNBD wrapper can be controlled through a control socket. When given, use PATH as file name, default is /var/run/xnbd-wrapper.ctl.

--xnbd-bgctl COMMAND

Specifies the path to the xnbd-bgctl executable. COMMAND can be a file name or a command to resolve to a file name using $PATH. By default, "xnbd-bgctl" resolved from $PATH is used.

--xnbd-server COMMAND

Specifies the path to the xnbd-server executable. The wrapper will spawn server instances on demand. COMMAND can be a file name or a command to resolve to a file name using $PATH. By default, "xnbd-server" resolved from $PATH is used.

(--xnbd-binary PATH)

Deprecated, please use --xnbd-server PATH instead. This option might be removed in future releases.

--cow

Invoke xnbd-server(8) instances using parameter --cow-target.

--readonly

Invoke xnbd-server(8) instances using parameter --readonly.

--max-queue-size NUMBER

Parameter forwarded to proxy mode xnbd-server on invocation. See xnbd-server(8) for details, please.

--max-buf-size NUMBER

Parameter forwarded to proxy mode xnbd-server on invocation. See xnbd-server(8) for details, please.

xnbd-client(1), xnbd-server(8), xnbd-wrapper-ctl(8)

The NBD kernel module and the NBD tools have been written by Pavel Macheck ([email protected]) and is now maintained by Paul Clements ([email protected]).

The xNBD userland programs have been written by Takahiro Hirofuchi ([email protected]).

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.