[Libguestfs] ANNOUNCE: nbdkit 1.22 - high performance NBD server

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 virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top