I'm pleased to announce the release of nbdkit 1.22, a high performance
plugin-based Network Block Device (NBD) server.
https://en.wikipedia.org/wiki/Network_block_device
Key features of nbdkit:
* Multithreaded NBD server written in C with good performance.
* Minimal dependencies for the basic server.
* Liberal license (BSD) allows nbdkit to be linked to proprietary
libraries or included in proprietary code.
* Well-documented, simple plugin API with a stable ABI guarantee.
Lets you export “unconventional” block devices easily.
* You can write plugins in C, Go, Lua, Perl, Python, OCaml, Ruby,
Rust, shell script or Tcl.
* Filters can be stacked in front of plugins to transform the output.
Git:
https://github.com/libguestfs/nbdkit
Download:
https://download.libguestfs.org/nbdkit/1.22-stable/
Fedora:
https://koji.fedoraproject.org/koji/packageinfo?packageID=16469
Debian:
https://packages.debian.org/nbdkit
Release notes (
http://libguestfs.org/nbdkit-release-notes-1.22.1.html)
These are the release notes for nbdkit stable release 1.22. This
describes the major changes since 1.20.
nbdkit 1.22.0 was released on 27 August 2020.
Security
There were no security issues found. All past security issues and
information about how to report new ones can be found in
nbdkit-security(1).
Plugins
New nbdkit-cdi-plugin(1) (Containerized Data Importer) lets you export
a single layer from a container image, allowing you to access disk
images distributed using container registry infrastructure.
New nbdkit-ondemand-plugin(1) creates filesystems for clients on
demand.
New nbdkit-torrent-plugin(1) serves a BitTorrent file or magnet link
over NBD.
nbdkit-data-plugin(1) and nbdkit-memory-plugin(1) have a new
"allocator" parameter giving more fine-grained control over the
allocation strategy. Currently implemented strategies are: sparse
array, sparse array with zstd compression, malloc, and malloc with
mlock.
nbdkit-data-plugin(1) data format now supports strings and alignment.
The "disk2data.pl" script has been enhanced to detect repeated
sequences and produce a more compact output.
nbdkit-curl-plugin(1) adds support for arbitrary custom request
headers. Also it now supports scripts for generating cookies and
custom request headers. This is especially useful when accessing web
servers that require authentication which has to be renewed
periodically.
nbdkit-curl-plugin(1) now supports HTTP/2 servers (David Edmondson,
Pino Toscano, Zi Liu).
nbdkit-curl-plugin(1) adds support for the "User-Agent" header.
nbdkit-file-plugin(1) can export multiple files in a directory as
separate exports (Eric Blake).
nbdkit-file-plugin(1) supports new "cache=none" and
"fadvise=normal|random|sequential" parameters which can be used to
optimize access patterns and avoid filling the page cache.
nbdkit-nbd-plugin(1) supports proxying to another NBD server over
"AF_VSOCK" (Eric Blake).
nbdkit-nbd-plugin(1) supports new "command=" and "socket-fd="
parameters which allow you to run a subordinate NBD server as a command
directly from the plugin, or pass in an already connected NBD endpoint.
nbdkit-streaming-plugin(1) supports streaming to and from local pipes.
nbdkit-vddk-plugin(1) now has support for VDDK 7.0. A new and useless
"error" message printed by VDDK 7 has been suppressed (thanks Ming Xie,
Pino Toscano).
nbdkit-ext2-plugin(1) has been removed. It was deprecated in
nbdkit 1.17.8. All existing uses can be replaced with
nbdkit-ext2-filter(1).
The "-" character is now permitted within plugin and filter names (Eric
Blake).
Filters
New nbdkit-ddrescue-filter(1) lets you test disk images recovered by
ddrescue(1) (François Revol).
New nbdkit-gzip-filter(1) can decompress a plugin that contains gzip-
compressed data. It replaces nbdkit-gzip-plugin(1) which is deprecated
and will be removed in nbdkit 1.26.
New nbdkit-pause-filter(1) can temporarily stop and later resume NBD
requests. This can be used when taking snapshots.
New nbdkit-swab-filter(1) swaps bytes in the underlying plugin, which
can be used to adjust images that have an incorrect byte order
(François Revol).
New nbdkit-tar-filter(1) reads and writes files inside a tar file in
the underlying plugin. It replaces nbdkit-tar-plugin(1) which is
deprecated and will be removed in nbdkit 1.26.
New nbdkit-tls-fallback-filter(1) provides alternate content when a
client connects without using TLS to a server that permits but does not
require TLS (Eric Blake).
nbdkit-fua-filter(1) has new option "fuamode=pass" to pass through FUA
and flush requests unchanged (disabling the filter). A new, unsafe
"fuamode=discard" mode was added which discards FUA and flush requests.
Language bindings
New nbdkit-cc-plugin(3) lets you write small nbdkit plugins as inline
C, C++ or OCaml "scripts" (and potentially other ahead-of-time compiled
programming languages).
nbdkit-rust-plugin(3) bindings have been replaced by higher level and
more idiomatic bindings. These also support a greater range of server
features (Alan Somers).
nbdkit-python-plugin(3) now supports parallel plugins. These cannot
run Python code in parallel (because of the Python GIL), but for Python
code that blocks, eg. calling out to external services, requests can
now be handled in parallel (thanks Nir Soffer).
nbdkit-python-plugin(3) has a greater range of examples (Nir Soffer).
nbdkit-python-plugin(3) adds support for getting the client export
name, calling "nbdkit_debug", and also for extents.
Server
"nbdkit --dump-config" has new fields: "version_major" and
"version_minor" to allow easier version parsing from scripts.
"host_cpu" and "host_os" so you can find out if nbdkit was
cross-
compiled for another platform. "zstd=(yes|no)" so you can find out if
nbdkit was compiled with zstd compression support.
The -e/--exportname option (which never did anything useful previously)
is now used to pass the preferred exportname to the --run option. In
general you should never use this option except in very limited and
exceptional circumstances (Eric Blake).
API
New ".after_fork" callback which can be used for plugins which need to
create background threads, since those threads would otherwise be
stranded if the server forks into the background. The VDDK plugin now
defers VDDK library initialization til ".after_fork" because it is
thought that the library creates background threads especially when
accessing remote servers.
New API "nbdkit_extents_aligned" is a helper function for filters that
retrieves extents as needed until at least a certain range is covered
(Eric Blake).
New "nbdkit_is_tls" can be called to determine if TLS was negotiated on
the connection. Plugins could use this to hide certain exports from
non-authenticated/non-encrypted clients (Eric Blake).
"nbdkit_read_password" with "password=-" will now return an
error if
the input is not a tty. Also "password=-FD" is disallowed if the file
descriptor is 0, 1 or 2.
Bug fixes
The VDDK plugin was extensively refactored to fix many bugs: Reading
passwords from a tty should work again. The plugin should now work
properly when daemonized or using the --run option. The threading
model has been relaxed to "SERIALIZE_REQUESTS" which should give small
performance improvements when using multiple connections.
The "base64" option of nbdkit-data-plugin(1) has been fixed so it sets
the implicit size correctly.
The "<FILE" formatter of nbdkit-data-plugin(1) now works if you use
it
more than once.
Documentation
New nbdkit-client(1) manual page documents how to mount filesystems
from NBD exports on client machines, either directly or using systemd
mountpoints.
Examples now use "NBDKIT_API_VERSION 2" so that the examples match the
documentation.
Tests
The tests should now pass on OpenBSD ≥ 6.4.
tests/Makefile.am was refactored: There is now no longer a single
massive "EXTRA_DIST". Creation of test disks was refactored.
Some tests will now use new libnbd 1.4 tools nbdcopy(1) and nbdinfo(1)
if available, and skip the tests otherwise.
New test functions "requires_plugin" and "requires_filter"
allows tests
to be skipped if the corresponding plugin/filter was not compiled on a
particular platform. So tests should now not fail when an optional
external library needed by a plugin/filter is not available.
Build
Honggfuzz may now be used for fuzz testing.
If nbdkit-python-plugin(3) is enabled, Python ≥ 3.6 must be used.
Internals
The export name is now passed down through filter ".open" callbacks,
allowing filters to modify the export name passed through to plugins.
The final thread model is passed to filter ".get_ready" callbacks.
SEE ALSO
nbdkit(1).
AUTHORS
Authors of nbdkit 1.22:
Alan Somers
(7 commits)
Eric Blake
(53 commits)
François Revol
(2 commits)
Nir Soffer
(2 commits)
Richard W.M. Jones
(285 commits)
--
Richard Jones, Virtualization Group, Red Hat
http://people.redhat.com/~rjones
Read my programming and virtualization blog:
http://rwmj.wordpress.com
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