Scroll to navigation

guestfs-release-notes-1.22(1) Virtualization Support guestfs-release-notes-1.22(1)


guestfs-release-notes - libguestfs Release Notes


These release notes only cover the differences from the previous stable/dev branch split (1.20.0). For detailed changelogs, please see the git repository, or the ChangeLog file distributed in the tarball.

New features


Remote access to disks:

  • Network Block Device (nbd)
  • Secure Shell (ssh)
  • HTTP and HTTPS
  • FTP and FTPS
  • iSCSI
  • Gluster
  • Ceph/rbd (Mike Kelly)
  • Sheepdog
  • TFTP

The SYSLINUX and EXTLINUX bootloaders can now be installed in disk images using the API.

Inspection can now handle filesystems such as btrfs where subvolumes are separately mountable (Matthew Booth).

"Attach methods" are now known as "backends". Compatibility with existing code is preserved.

Filenames can contain ':', as long as newer QEMU is being used.


Virt-alignment-scan and virt-df scan multiple guests in parallel.

Guestmount now passes errno accurately back to userspace in almost all cases.

Guestfish and other tools can now use a URI-like syntax to access remote disks, eg:

 guestfish -a ssh://

Guestfish and guestmount now allow you to specify the filesystem type when mounting, which is more secure (Dave Vasilevsky).

Guestfish is now the "guest filesystem shell".

Guestfish allows only 1 "true" "t" "yes" "y" "on" 0 "false" "f" "no" "n" "off" for boolean values (case insensitive), and gives an error for all other strings.

New tool "guestunmount" for unmounting FUSE filesystems safely.

"guestmount --no-fork" flag prevents guestmount from daemonizing.

Virt-resize now uses sparse copies by default, saving considerable space for guests which are mostly empty.

Bash tab completion has been rewritten and can now handle most tools, and correctly tab-complete "--long" options. In addition, bash completion scripts are loaded on demand.

Language bindings

The Java API now supports events.

The Python object now inherits from the "object" base class.

Python methods which previously returned lists of tuples can now be made to return a Python dict. For backwards compatibility, you have to enable this by using the constructor option "guestfs.GuestFS (python_return_dict=True)".

The PHP bindings are now tested properly, and have had multiple fixes.

The long-deprecated Perl "Sys::Guestfs::Lib" library has been removed.


New example program showing how to enable debugging and capture log messages.


Distributors can add arbitrary extra packages to the appliance by doing:

 ./configure --with-extra-packages="list of package names"

Distributors can use:

 ./configure --with-supermin-extra-options="..."

to add arbitrary extra options to supermin.


No security issues were found in this release.

New APIs


C only:



The febootstrap tool has now been renamed to "supermin". Libguestfs can use either, but now prefers "supermin".

libxml2 is required to build libguestfs.

The hivexregedit program (from hivex) is required to build from git.

Internal functions can no longer be used unless the caller defines "-DGUESTFS_PRIVATE=1".

Enable C compiler warnings in Python, Ruby bindings.

Fail early and clearly if libvirt does not support qemu/KVM (eg. if default libvirt connection is to Xen).

"make print-subdirs" rule, useful for selectively running tests.

Multiple fixes to allow separated (sourcedir != builddir) builds.

Multiple fixes to Haskell bindings.

"ln" and "ln-f" APIs now capture "errno" correctly.

Language binding tests use (mostly) a standard numbering scheme and aim to test the same range of features in each language. Also the number of launches required has been reduced so these tests should run much more quickly.

Library code internally uses GCC "__attribute__((cleanup))" (if available) to simplify memory allocation.

Internal header files have been reorganized. See the comments in src/guestfs-internal*.h

Internal code shared between the library and certain tools is now located in a static "libutils" library.

Almost all subdirectories can now use parallel builds, although note that the top-level directories still build in series.

Use of "PATH_MAX" and "NAME_MAX" has been eliminated from the code.

The Java API now requires JVM ≥ 1.6.

Force use of "serial-tests" with automake ≥ 1.12.

Use of sockets in the library protocol layer is abstracted, allowing other non-POSIX layers to be added in future (see src/conn-socket.c).

"qemu-img info --output json" is used if available, for more secure parsing of the output of this command.

Distros can now use "make INSTALLDIRS=vendor install" to place Ruby bindings in vendordir. This eliminates a non-upstream patch carried by both Fedora and Debian.

Valgrind log files are now written to tmp/valgrind-DATE-PID.log

"make clean" cleans the local "tmp/" directory.

The C API tests have been rewritten using a more flexible generator language that allows arbitrary C code to be executing during tests.

Bugs fixed
Segfault in inspect-fs.c in mountable code
tar-out and base64-out quoting error
libguestfs: error: btrfsvol:/dev/sda2/root: root device not found: only call this function with a root device previously returned by guestfs_inspect_os
inspection fails if libosinfo is not installed
file on zero-sized file now produces "empty " instead of "empty"
qemu: could not open disk image /tmp/.../snapshot1: Permission denied
"error: external command failed, see earlier error messages" message needs to change
libguestfs should use --output json (if supported) to safely parse the output of qemu-img command
feature request: guestmount --with-cleanup-pipefd
oom-killer kills guestfsd when tar-in a lot of data
FileIn commands cause segfault if appliance dies during the file copy in
Misc leaks in virNetClientProgramCall in libvirt 1.0.2
Security context on image file gets reset
libguestfs-test-tool --qemu segfaults
Unexpected non-tail recursion in recv_from_daemon results in stack overflow in very long-running API calls that send progress messages
virt-tar fails on non-existent directory names "error in chunked encoding at /home/rjones/d/libguestfs/tools/virt-tar line 272."
virt-cat fails on directory names "/dev/stdout: error in chunked encoding"
btrfs causes subsequent ntfs-3g filesystem to fail
"No such file or directory" when execute "hivex-commit"
btrfs_subvolume_list broken due to change in subvolume list output
guestmount: rename() incorrectly follows symbolic links
guestmount: link() incorrectly returns ENOENT, when it should be EXDEV
checksums-out fail to compute the checksums of all regular files in directory
libguestfs FTBFS on Fedora 19 because of new ruby
virt-sysprep: Setting hostname, domain name and pretty name on Fedora 18 correctly
pvcreate fails if partition contains a swap signature
zero_free_space: open: /sysroot//ujqqq135.rd3: Cannot allocate memory
libguestfs with libvirt attach-method fails with odd error if default hypervisor is Xen
Adding a zero-length virtio-scsi disk causes: qemu-kvm: hw/scsi-bus.c:1568: scsi_req_complete: Assertion `req->status == -1' failed.
libguestfs cannot open disk images which are symlinks to files that contain ':' (colon) character
RFE: Allow to set log callback in Ruby bindings


guestfs-examples(1), guestfs-faq(1), guestfs-performance(1), guestfs-recipes(1), guestfs-testing(1), guestfs(3), guestfish(1),


Richard W.M. Jones


Copyright (C) 2009-2023 Red Hat Inc.


This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.


To get a list of bugs against libguestfs, use this link:

To report a new bug against libguestfs, use this link:

When reporting a bug, please supply:

  • The version of libguestfs.
  • Where you got libguestfs (eg. which Linux distro, compiled from source, etc)
  • Describe the bug accurately and give a way to reproduce it.
  • Run libguestfs-test-tool(1) and paste the complete, unedited output into the bug report.
2024-01-05 libguestfs-1.52.0