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guestfsd(8) Virtualization Support guestfsd(8)


guestfsd - guestfs daemon


 guestfsd [-r] [-v|--verbose]


"guestfsd" is the libguestfs daemon. Normal users never need to run this program explicitly. This man page discusses what "guestfsd" does in both the libguestfs appliance and when using libguestfs live.


For the architecture of the libguestfs appliance, see "ARCHITECTURE" in guestfs(3).

After the appliance boots, the /init script in the appliance starts "guestfsd" with no arguments. "guestfsd" opens the virtio-serial port on a known path (see "FILES"). It initiates the protocol (see "COMMUNICATION PROTOCOL" in guestfs(3)) and processes requests one at a time from the library until the appliance is destroyed.

Filesystems are mounted under /sysroot and all filesystem operations happen relative to this directory.


In the libguestfs live case, "guestfsd -r" is started from the rc-scripts, systemd, etc.

The "-r" option causes the daemon to operate on the root filesystem instead of /sysroot.

Currently (because of limitations in virtio-serial) only one client can connect at a time, and "guestfsd" must be restarted after each client disconnects. If libguestfs live were changed to use a different transport such as TCP/IP then this limitation could be removed.


Display brief help.
Pass the name of the virtio-serial channel, serial port, etc. over which guestfsd will communicate with the library. If this parameter is not given, then an internal default port is used.

The "fd:N" form causes guestfsd to use the file descriptor "N" directly.

Instead of opening the "guestfs_channel" and thus expecting that it already exists, create the channel as a Unix domain socket, listen on it, and accept a single connection. This is mainly used for testing the daemon.
Enable network features in the daemon.
Set the root filesystem to be / (instead of the default which is /sysroot). Also do not unmount filesystems when the daemon exits.

This option is used to enable libguestfs live.

Enable verbose messages for debugging.

The verbose flag is also set if the Linux command line contains the substring "guestfs_verbose=1".


This program returns 0 if successful, or non-zero if there was an error.


The virtio serial port which "guestfsd" connects to.
The Linux command line is parsed to discover "guestfs_*" flags. The following flags are understood:
Enable verbose messages. This flag is passed by the libguestfs library to the appliance to make the daemon more verbose (it acts like the -v flag on the command line). Unrelated to the daemon, it also causes the appliance init script to print out a lot more debugging information.
Set the path to the virtio-serial channel to something other than the default (which is /dev/virtio-ports/ This is used by the User-Mode Linux backend to use a regular emulated serial port instead of virtio-serial.
This is set if the appliance network is enabled (see "guestfs_set_network").




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