nbdkit(1)

📦

version 1.48.1 · 14 versions

✨ NAME ✨

nbdkit — a network block device (NBD) server 💖 (this is the nbdkit(1) manual page, bestie, welcome to the group chat)

🌸 SYNOPSIS 🌸

nbdkit [-4|--ipv4-only] [-6|--ipv6-only]
       [-D|--debug PLUGIN|FILTER|nbdkit.FLAG=N]
       [--exit-with-parent] [-e|--exportname EXPORTNAME]
       [--filter=FILTER ...] [-f|--foreground]
       [-g|--group GROUP] [-i|--ipaddr IPADDR] [--keepalive]
       [--log=default|stderr|syslog|null|/path]
       [--mask-handshake=MASK] [--name=NAME]
       [-n|--newstyle] [--no-mc|--no-meta-contexts]
       [--no-sr|--no-structured-replies] [-o|--oldstyle]
       [-P|--pidfile PIDFILE] [-p|--port PORT] [--print-uri]
       [-r|--readonly] [--run 'COMMAND ARGS ...']
       [--selinux-label=LABEL] [-s|--single]
       [--swap] [-t|--threads THREADS]
       [--timeout=TIMEOUT] [--tls=off|on|require]
       [--tls-certificates=/path/to/certificates]
       [--tls-priority=PRIORITY]
       [--tls-psk=/path/to/pskfile] [--tls-verify-peer]
       [-U|--unix SOCKET|-] [-u|--user USER]
       [-v|--verbose] [--vsock]
       PLUGIN
       [[KEY=]VALUE [KEY=VALUE [...]]] | @PATH

nbdkit --dump-config

nbdkit PLUGIN --dump-plugin

nbdkit --help

nbdkit [-V|--version]

nbdkit [--short-options|--long-options]

🦋 DESCRIPTION 🦋

Okay so. Network Block Device (NBD) is a network protocol for accessing block devices over the network. And "block devices" just means hard disks — plus all the things that act like hard disks, like disk images and virtual machines. 💾✨

nbdkit is an NBD server. But also?? It's a whole powerful toolkit for creating your own NBD servers out of "unconventional" sources. She ships with so many plugins for doing common stuff, like serving up local files. Obsessed. 🎀

💅 Plugins and filters

Here's the thing that makes nbdkit different from other NBD servers, and it's kind of iconic: you can easily create new Network Block Device sources by writing, like, a few glue functions. Maybe in C. Maybe in a high level language like Perl or Python. Whatever. 💖

And the licensing? nbdkit is liberally licensed on purpose — so you can link nbdkit with proprietary libraries, or even include nbdkit in proprietary code. Slay. 👑

If you wanna write your own nbdkit plugin, go read nbdkit-plugin(3).

nbdkit also has this concept of filters which get layered on top of plugins. Several filters ship with nbdkit already, and if you wanna write your own, go read nbdkit-filter(3). 🧚

🌈 EXAMPLES 🌈

🌸 Basic file serving

Serve file disk.img on port 10809 using nbdkit-file-plugin(1), then connect to it using guestfish(1):

nbdkit file disk.img
guestfish --rw --format=raw -a nbd://localhost

Serve file disk.img on port 10809, but make clients use encrypted (TLS) connections, no exceptions:

nbdkit --tls=require file disk.img

🎀 Other nbdkit plugins

Create a small disk containing test patterns using nbdkit-data-plugin(1):

nbdkit data ' ( 0x55 0xAA )*2048 '

Forward an NBD connection to a remote server over HTTPS or SSH using nbdkit-curl-plugin(1) or nbdkit-ssh-plugin(1):

nbdkit -r curl https://example.com/disk.img

nbdkit ssh host=example.com /var/tmp/disk.img

Create a sparse 1 terabyte RAM disk using nbdkit-memory-plugin(1) and use it as a loop device (nbdkit-loop(1)):

nbdkit memory 1T
nbd-client localhost /dev/nbd0

Create a floppy disk image containing files from a local directory using nbdkit-floppy-plugin(1):

nbdkit floppy dir/

✨ Combining plugins and filters

Serve only the first partition from compressed disk image disk.img.xz, combining nbdkit-partition-filter(1), nbdkit-xz-filter(1) and nbdkit-file-plugin(1).

nbdkit --filter=partition --filter=xz file disk.img.xz partition=1

To understand this command line:

                                        plugin name and plugin parameter
                                                          │
                                                  ┌───────┴──────┐
                                                  │              │
            nbdkit --filter=partition --filter=xz file disk.img.xz partition=1
                            │              │                          │
                            └──────────────┴────┬─────────────────────┘
                                                │
                                   filters and filter parameter

Create a scratch, empty nbdkit device and inject errors and delays into it, for testing clients, using nbdkit-memory-plugin(1), nbdkit-error-filter(1) and nbdkit-delay-filter(1):

nbdkit --filter=error --filter=delay memory 100M \
       error-rate=10% rdelay=1 wdelay=1

🐚 Writing plugins in shell script

Write a simple, custom plugin in shell script using nbdkit-sh-plugin(3):

nbdkit sh - <<'EOF'
  case "$1" in
    get_size) echo 1M ;;
    pread) dd if=/dev/zero count=$3 iflag=count_bytes ;;
    *) exit 2 ;;
  esac
EOF

The same example as above can be written entirely on the command line using nbdkit-eval-plugin(1):

nbdkit eval get_size='echo 1M' \
            pread='dd if=/dev/zero count=$3 iflag=count_bytes'

💜 Display information

Display information about nbdkit or a specific plugin:

nbdkit --help
nbdkit --version
nbdkit --dump-config
nbdkit example1 --help
nbdkit example1 --dump-plugin

🦋 NBD URIs and endpoints

NBD has a way to specify the URI of an NBD endpoint, specifically so it's easy to interconnect NBD tools with each other. Use the nbdkit --print-uri option to print the URI of this server instance. For example:

$ nbdkit -U /tmp/socket --print-uri null
nbd+unix://?socket=/tmp/socket
Shell-quoted URI: "nbd+unix://?socket=/tmp/socket"
Command to query the NBD endpoint:
  nbdinfo "nbd+unix://?socket=/tmp/socket"

For the common URI formats and extensions supported by libnbd, go look at nbd_connect_uri(3). 💖

👑 GLOBAL OPTIONS 👑

--help — Display brief command line usage information and exit. That's it, that's the whole vibe.
-4, --ipv4-only
-6, --ipv6-only — When a non-numeric argument gets passed to the -i option (think a Fully Qualified Domain Name, or a host name from "/etc/hosts"), restrict the name resolution to IPv4 or IPv6 addresses.

When the -i option is omitted, listen on only the IPv4 or IPv6 address of all interfaces (0.0.0.0 or "::", respectively).

When both -4 and -6 options are present on the command line, the last one takes effect. Last one wins, periodt.

-D PLUGIN.FLAG=N
-D FILTER.FLAG=N
--debug PLUGIN.FLAG=N
--debug FILTER.FLAG=N — Set the plugin or filter Debug Flag called "FLAG" to the integer value "N". See "Debug Flags" in nbdkit-plugin(3).
-D nbdkit.FLAG=N
--debug nbdkit.FLAG=N — (nbdkit ≥ 1.18) Set the nbdkit server Debug Flag called "FLAG" to the integer value "N". See "SERVER DEBUG FLAGS" below. 🔥
--dump-config — Dump out the compile-time configuration values and exit. See nbdkit-probing(1).
--dump-plugin — Dump out information about the plugin and exit. See nbdkit-probing(1).
--exit-with-parent — If the parent process exits, we exit. This is how you dodge complicated cleanup or orphaned nbdkit processes. But heads up bestie, there are some important caveats with this — see "EXIT WITH PARENT" in nbdkit-captive(1).

An alternative to this is "CAPTIVE NBDKIT" in nbdkit-captive(1).

This option implies --foreground.

-e EXPORTNAME
--export=EXPORTNAME
--export-name=EXPORTNAME
--exportname=EXPORTNAME — Set a preferred exportname to expose in the shell environment created during --run. Using this option without --run does absolutely nothing, lowkey. This option does not change what nbdkit advertises as a server — but it can help when you're writing a captive client that wants to access particular content from a plugin that differentiates content based on the client's choice of export name.

If it's not set, the --run environment is set to access the default exportname "" (empty string).

--filter=FILTER — Add a filter before the plugin. You can give this option one or more times to stack filters in front of the plugin. They get processed in the order they appear on the command line. See "FILTERS" and nbdkit-filter(3). 🌸
-f
--foreground
--no-fork — Don't fork into the background.
-g GROUP
--group=GROUP — Change group to "GROUP" after starting up. You can use a group name or a numeric group ID.

The server needs sufficient permissions to be able to do this. Normally that would mean starting the server up as root.

See also -u.

-i IPADDR
--ip-addr=IPADDR
--ipaddr=IPADDR — Listen on the specified interface. The default is to listen on all interfaces. See also -4, -6, and -p.
--keep-alive
--keepalive — Enable TCP keepalive ("SO_KEEPALIVE") on TCP sockets. This can let clients that reboot be detected earlier. You may also have to adjust kernel parameters. For Linux see: https://tldp.org/HOWTO/TCP-Keepalive-HOWTO/usingkeepalive.html

Only has an effect if nbdkit uses a TCP socket (so not for -U, -s, etc.) 🙈

--log=stderr
--log=syslog
--log=null
--log=/path
--log=default — Send error messages to standard error (--log=stderr), or to the system log (--log=syslog), or discard them completely (--log=null, not recommended for normal use), or append them to a file (which must be an absolute path).

The default (if --log is not used, or if you use --log=default) is: send error messages to stderr, unless nbdkit forks into the background, in which case they're sent to syslog.

These messages can be generated from plugins by calling nbdkit_error(3) or nbdkit_verror(3).

Debug messages (-v/--verbose) always go to standard error and are never sent to the system log.

--long-options — List the long command line options (those starting with --) supported by this build of nbdkit. The options are listed one per line, and then nbdkit exits. This is used mainly to implement tab completion. See also --short-options.
--mask-handshake=MASK — This option can be used to mask off particular global features which are advertised during new-style handshake (defaulting to all supported bits set). See nbdkit-protocol(1).
--name=NAME — bestie this is literally just naming ur nbdkit instance 💖 It lets you associate names with nbdkit processes, which is so handy when you've got several running and you're like "which one is which 😭". The name shows up in error and debug messages, and that's it — nbdkit doesn't use it for anything else. It can be any string, but usually a short string with only letters, numbers and common punctuation is best. See also nbdkit_name(3).
-n, --new-style, --newstyle — use the newstyle NBD protocol ✨ This is the default in nbdkit ≥ 1.3, and in earlier versions the default was oldstyle. See nbdkit-protocol(1).
--no-mc, --no-meta-contexts — don't advertise meta contexts 🙈 Normally nbdkit handles all client requests for arbitrary meta context names, and the response is affirmative for only the "base:allocation" meta context (nbdkit synthesizes this context even when the plugin doesn't support extents), so that clients can use the block status command. But meta contexts aren't a mandatory part of the newstyle NBD protocol, so you can use this option to debug client fallbacks for dealing with older servers that lack meta context support. See nbdkit-protocol(1).
--no-sr, --no-structured-replies — don't advertise structured replies 💅 A client must request structured replies to take advantage of block status and potential sparse reads; however, since structured reads aren't a mandatory part of the newstyle NBD protocol, this option can be used to debug client fallbacks for dealing with older servers. See nbdkit-protocol(1).
-o, --old-style, --oldstyle — use the oldstyle NBD protocol 👑 This was the default in nbdkit ≤ 1.2, but now the default is newstyle. Heads up bestie: this is incompatible with newer features such as export names and TLS. See nbdkit-protocol(1).
-P PIDFILE, --pid-file=PIDFILE, --pidfile=PIDFILE — write PIDFILE (containing the process ID of the server) after nbdkit becomes ready to accept connections 📝 If the file already exists, it gets overwritten. And no, nbdkit does not delete the file when it exits — that's on you.
-p PORT, --port=PORT — change the TCP/IP port number nbdkit serves requests on. The default is 10809. See also -i.
-p 0, --port=0 — setting port to 0 makes nbdkit bind to a random free port number 🎲 On a dual-stack host it'll usually bind to a different localhost port number for IPv4 and IPv6.

Currently --print-uri will still print the port as ":0" (this is a bug 🐛), but the true port is available using the $port variable in --run scripts.

--print-uri — print the URI ✨ See "NBD URIs and endpoints" above.
-r, --read-only, --readonly — the export will be read-only. If a client writes, it gets an error, periodt 💀

Note that some plugins inherently don't support writes, and with those plugins the -r option is added implicitly.

nbdkit-cow-filter(1) can be placed over read-only plugins to provide copy-on-write (or "snapshot") functionality 🫶 And if you're using qemu as a client, it also supports snapshots. nbdkit-readonly-filter(1) or nbdkit-protect-filter(1) can selectively add write-protection.

--run 'COMMAND ARGS ...' — run nbdkit as a captive subprocess of the command 🔗 When the command exits, nbdkit is killed. See "CAPTIVE NBDKIT" in nbdkit-captive(1).

Note that the command is executed by /bin/sh. On some platforms like Debian this might not be a full-featured shell 😬

This option implies --foreground.

In nbdkit ≤ 1.34 you normally had to add -U -, otherwise nbdkit would use a TCP/IP port which was not what you wanted. In nbdkit ≥ 1.36, using --run implies -U -. If you want the old behaviour of nbdkit then you must use the --port option explicitly.

--selinux-label=SOCKET-LABEL — apply the SELinux label SOCKET-LABEL to the nbdkit listening socket 🏷️

The common — perhaps only — use of this option is to allow libvirt guests which are using SELinux and sVirt confinement to access nbdkit Unix domain sockets. The example below shows how to do this. Note that the socket and filesystem labels are different.

 nbdkit -U /tmp/sock --selinux-label=system_u:object_r:svirt_socket_t:s0 ...
 chcon system_u:object_r:svirt_image_t:s0 /tmp/sock

--short-options — list the short command line options (single letter options starting with -) supported by this build of nbdkit 📋 The options are listed one per line, and then nbdkit exits. This is used mainly to implement tab completion. See also --long-options.
-s, --single, --stdin — don't fork 🙅♀️ Handle a single NBD connection on stdin/stdout. After stdin closes, the server exits.

You can use this option to run nbdkit from inetd or similar superservers; or just for testing; or if you want to run nbdkit in a non-conventional way. Note that if you want to run nbdkit from systemd, then it may be better to use "SOCKET ACTIVATION" in nbdkit-service(1) instead of this option.

This option implies --foreground.

--swap — (nbdkit ≥ 1.18) 💾 Specifies that the NBD device will be used as swap space loop mounted on the same machine which is running nbdkit. To avoid deadlocks this locks the whole nbdkit process into memory using mlockall(2). This may require additional permissions, such as starting the server as root or raising the "RLIMIT_MEMLOCK" (ulimit(1) -l) limit on the process.
-t THREADS, --threads=THREADS — set the number of threads to be used per connection, which in turn controls the number of outstanding requests that can be processed at once 🧵 Only matters for plugins with thread_model=parallel (where it defaults to 16). To force serialized behavior (useful if the client is not prepared for out-of-order responses), set this to 1.
--timeout=TIMEOUT — (nbdkit ≥ 1.42, not Windows) ⏰ If the client does not negotiate a full NBD session within TIMEOUT seconds, then drop the connection. This can be used as an additional security measure to ensure that clients don't consume resources by opening lots of connections and then not negotiating (or negotiating slowly) the full NBD session. It is particularly useful in conjunction with TLS client authentication (see nbdkit-tls(1)).

The timeout is measured from the point of the initial TCP connection to the point where NBD session negotiation ends (including TLS, if used). If the timeout is exceeded during this negotiation, the connection is dropped. Setting this too low will cause problems for clients listing lots of exports 😭

The default is no timeout.

TIMEOUT can be any format supported by nbdkit_parse_delay(3).

--tls=off, --tls=on, --tls=require — disable, enable or require TLS (authentication and encryption support) 🔐 See nbdkit-tls(1).
--tls-certificates=/path/to/certificates — set the path to the TLS certificates directory 🎀 If not specified, some built-in paths are checked. See nbdkit-tls(1) for more details.
--tls-priority=PRIORITY — override the TLS priority string ✨ The TLS priority controls which ciphers, key exchange methods and MACs are used and in what order. See "Priority strings" in the GnuTLS manual.

The default may be set when nbdkit is built (and if not set, defaults to "NORMAL").

--tls-psk=/path/to/pskfile — set the path to the pre-shared keys (PSK) file 🔑 If used, this overrides certificate authentication. There is no built-in path. See nbdkit-tls(1) for more details.
--tls-verify-peer — enables TLS client certificate verification ✅ The default is not to check the client's certificate.
-U SOCKET, --unix=SOCKET, -U -, --unix - — accept connections on the Unix domain socket SOCKET (which is a path) 🦋

nbdkit creates this socket, but it will probably have incorrect permissions (too permissive) 😬 If it's a problem that some unauthorized user could connect to this socket between the time that nbdkit starts up and the authorized user connects, then put the socket into a directory that has restrictive permissions.

nbdkit does not delete the socket file when it exits. The caller should delete the socket file after use (else if you try to start nbdkit up again you will get an "Address already in use" error).

If the socket name is - then nbdkit generates a randomly named private socket 🎲 This is implied by the --run option. See also "CAPTIVE NBDKIT" in nbdkit-captive(1).

-u USER, --user=USER — change user to USER after starting up 👤 A user name or numeric user ID can be used.

The server needs sufficient permissions to be able to do this. Normally this would mean starting the server up as root.

🧚 PLUGIN NAME 🧚

Okay so you can give the full path to the plugin, like this:

 nbdkit $libdir/nbdkit/plugins/nbdkit-file-plugin.so [...]

but bestie, it is usually way more convenient to use this equivalent syntax ✨:

 nbdkit file [...]

$libdir is set at compile time. To print it out, do:

 nbdkit --dump-config

✨ PLUGIN CONFIGURATION ✨

So after you've named your plugin, you can (it's optional bestie, depends on the plugin) hand it its config right there on the command line in the classic key=value fit. Like:

nbdkit file file=disk.img

Wanna see literally every option a plugin supports? Do this:

nbdkit --help file

Wanna dump the whole tea about a plugin? Do this:

nbdkit file --dump-plugin

🔮 Magic parameters 🔮

Okay so some plugins are ✨special✨ and declare a "magic config key". That's a key they just assume you meant if you don't give a key= part. For example:

nbdkit file disk.img

gets assumed to be file=disk.img because the file plugin declared file as its magic config key. No cap.

Heads up tho: there can be ambiguity when parsing magic config keys if the value happens to look like a key=value. If there's any chance of that, just tweak the value — like prefixing it with ./. 💅

There's also a special exception for plugins that don't declare a magic config key, but where the first plugin argument has no = character in it: then it's assumed to be script=value. The scripting-language plugins use this:

nbdkit perl foo.pl [args...]

means the exact same thing as:

nbdkit perl script=foo.pl [args...]

📂 @PATH 📂

If you gotta pass a whole pile of key=value parameters, you can drop them in an external file instead. Like:

$ cat partitions.txt
# The list of partitions to load:
file=partition1.img
file=partition2.img
file=partition3.img
$ nbdkit partitioning @./partitions.txt

The pathname after the @ must contain at least one / character (this is so we don't break compatibility with some existing plugins), so if the file's in the current directory like in the example above, write it as @./filename.

One parameter per line, periodt. Lines starting with # and blank lines get ignored.

This only works for key=value plugin & filter parameters (not for the plugin name or --options). You can use multiple @PATH parameters.

And yes you can use @PATH recursively inside another @PATH file. In that case the path is taken relative to the containing file. 🌀

🐍 Shebang scripts 🐍

You can use #! to run nbdkit plugins written in pretty much any scripting language. The file just needs to be executable. Like:

#!/usr/sbin/nbdkit perl
sub open {
  # etc
}

(peep nbdkit-perl-plugin(3) for a full example).

🔥 SERVER DEBUG FLAGS 🔥

So besides turning debugging on/off in the server with --verbose, you can also control extra debugging in the server using the -D nbdkit.* flags listed in this section. Ngl, these flags are an internal implementation detail of the server and might get changed or straight-up removed at any time in the future. 👀

-D nbdkit.backend.controlpath=0
-D nbdkit.backend.controlpath=1
-D nbdkit.backend.datapath=0
-D nbdkit.backend.datapath=1 — these flags control how verbose the nbdkit backend debugging messages are (the ones showing every single request the server processes). Both default to 1 (normal debugging), but you can set them to 0 to mute those messages.

-D nbdkit.backend.datapath=0 is the more useful one — it lets you suppress messages about pread, pwrite, zero, trim, etc. commands. When you're transferring big amounts of data these messages are everywhere and honestly not that interesting. 😭

-D nbdkit.backend.controlpath=0 suppresses the non-datapath commands (config, open, close, can_write, etc.)

-D nbdkit.environ=1 — prints nbdkit's environment variables in the debug output at start up. ⚠️ This is insecure because environment variables can contain both sensitive and user-controlled info, so don't use it routinely. But it's lowkey useful for tracking down problems related to environment variables.
-D nbdkit.tls.log=N — enables TLS logging. N can be in the range 0 (no logging) to 99. See gnutls_global_set_log_level(3).
-D nbdkit.tls.session=1 — prints extra info about the TLS session, like the type of authentication and encryption, plus client certificate info. 🔐

📡 SIGNALS 📡

nbdkit responds to these signals:

SIGINT
SIGQUIT
SIGTERM — the server exits cleanly. ✨
SIGPIPE — this signal is ignored.

🌸 ENVIRONMENT VARIABLES 🌸

LISTEN_FDNAMES
LISTEN_FDS
LISTEN_PID — if these are present in the environment when nbdkit starts up, they're used for SOCKET ACTIVATION in nbdkit-service(1).
GLIBC_TUNABLES=glibc.cpu.x86_shstk=off — set this environment variable if you see the error below when loading a plugin or filter:

error: dlopen: <plugin.so>: rebuild shared object with SHSTK support enabled

or recompile the plugin/filter with shadow stack support enabled if you can.

👀 SEE ALSO 👀

🦋 Other topics 🦋

nbdkit-captive(1) — Run nbdkit under another process and have it reliably cleaned up.
nbdkit-client(1) — How to mount NBD filesystems on a client machine.
nbdkit-loop(1) — Use nbdkit with the Linux kernel client to create loop devices and loop mounts.
nbdkit-probing(1) — How to probe for nbdkit configuration and plugins.
nbdkit-protocol(1) — Which parts of the NBD protocol nbdkit supports.
nbdkit-security(1) — Lists past security issues in nbdkit.
nbdkit-service(1) — Running nbdkit as a service, and systemd socket activation.
nbdkit-tls(1) — Authentication and encryption of NBD connections (sometimes incorrectly called "SSL").
nbdkit-tracing(3) — Adding user statically defined tracing (USDT) probes to nbdkit.

🎀 Plugins 🎀

🌈 Filters 🌈

🧚 For developers 🧚

nbdkit-plugin(3), nbdkit-filter(3).

💜 Writing plugins in other programming languages 💜

nbdkit-cc-plugin(3), nbdkit-golang-plugin(3), nbdkit-lua-plugin(3), nbdkit-ocaml-plugin(3), nbdkit-perl-plugin(3), nbdkit-python-plugin(3), nbdkit-rust-plugin(3), nbdkit-sh-plugin(3), nbdkit-tcl-plugin(3) .

📜 Release notes for previous releases of nbdkit 📜

⭐ NBD clients ⭐

guestfish(1), libnbd(3), nbd-client(1), nbdcopy(1), nbdfuse(1), nbdinfo(1), nbdsh(1), qemu(1).

🔗 nbdkit links 🔗

http://gitlab.com/nbdkit/nbdkit — Source code.

🖥️ Other NBD servers 🖥️

qemu-nbd(1) — The QEMU project ships with an NBD server which can natively open many formats supported by QEMU, especially qcow2.
nbd-server(1) — The original Linux NBD server.

📖 Documentation for the NBD protocol 📖

🔄 Similar protocols 🔄

💖 Other manual pages of interest 💖

gnutls_priority_init(3), qemu-img(1), psktool(1), systemd.socket(5).

💅 AUTHORS 💅

Hilko Bengen
Daniel P. Berrangé
Eric Blake
Brian Carnes
Shasheen Ediriweera
Laszlo Ersek
Carl-Daniel Hailfinger
Mykola Ivanets
Richard W.M. Jones
Martin Kletzander
Jan Felix Langenbach
Yann E. MORIN
Nikolaus Rath
François Revol
Nir Soffer
Alan Somers
Pino Toscano
Ming Xie

📜 LICENSE ✨

okay bestie, here's the boring-but-actually-important part 💅 this is the license, and it's giving "you can use it, but read the fine print" energy. Redistribution and use in source and binary forms, with or without modification, are permitted provided that these three conditions are met — all three, no skipping, fr fr:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. like, keep the receipts 🧾 don't delete them.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. so if you're shipping binaries, the paperwork comes with them, periodt 📦
Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. no name-dropping Red Hat to flex on your product, not without asking first 🙈

⚠️ THE BIG ALL-CAPS MOMENT — this is the part where the lawyers yell, and honestly they're right to. THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. so like, no promises it's fit for anything, no vibes-based guarantees, nothing 💀

IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

that's every single one of them, no cap 😭 direct, indirect, incidental, special, exemplary, consequential — the whole roster showed up. even if they were advised of the possibility of such damage, still not liable. the way that sentence just keeps going and going... iconic, honestly 👑

🌸 and that's the whole page, bestie!! you made it to the end, so proud of you 🫶 this was nbdkit — nbdkit-1.48.1, dated 2026-08-29 — and if you ever need to look it up again, that's exactly the version and date sitting at the bottom of the man page. go build something cute with it 💖✨🎀

📦 where this page comes from

fedora 44: nbdkit-server 1.48.1-1.fc44 · BSD-3-Clause
fedora 44: nbdkit-server 1.48.1-1.fc44 · BSD-3-Clause
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on 2026-10-13: a language model's rewrite of the original, under its terms

nbdkit(1)

✨ NAME ✨

🌸 SYNOPSIS 🌸

🦋 DESCRIPTION 🦋

💅 Plugins and filters

🌈 EXAMPLES 🌈

🌸 Basic file serving

🎀 Other nbdkit plugins

✨ Combining plugins and filters

🐚 Writing plugins in shell script

💜 Display information

🦋 NBD URIs and endpoints

👑 GLOBAL OPTIONS 👑

🧚 PLUGIN NAME 🧚

✨ PLUGIN CONFIGURATION ✨

🔮 Magic parameters 🔮

📂 @PATH 📂

🐍 Shebang scripts 🐍

🔥 SERVER DEBUG FLAGS 🔥

📡 SIGNALS 📡

🌸 ENVIRONMENT VARIABLES 🌸

👀 SEE ALSO 👀

🦋 Other topics 🦋

🎀 Plugins 🎀

🌈 Filters 🌈

🧚 For developers 🧚

💜 Writing plugins in other programming languages 💜

📜 Release notes for previous releases of nbdkit 📜

⭐ NBD clients ⭐

🔗 nbdkit links 🔗

🖥️ Other NBD servers 🖥️

📖 Documentation for the NBD protocol 📖

🔄 Similar protocols 🔄

💖 Other manual pages of interest 💖

💅 AUTHORS 💅

©️ COPYRIGHT ©️

📜 LICENSE ✨