guestfs-building - Man Page

This manual page describes how to build libguestfs from source.

The main steps are:

• Install the requirements.
• Build, either from the git repository or from a tarball.
• Run the tests.
• Run the tools from the source directory, or install.

You will need to install additional dependencies autoconf, automake, gettext, OCaml findlib and po4a when building from git.

 git clone https://github.com/libguestfs/libguestfs
 cd libguestfs
 git submodule update --init
 autoreconf -i
 ./configure CFLAGS=-fPIC
 make

Tarballs are downloaded from http://download.libguestfs.org/. Stable tarballs are signed with the GnuPG key for rich@annexia.org, see https://pgp.mit.edu/pks/lookup?op=vindex&search=0x91738F73E1B768A0. The fingerprint is F777 4FB1 AD07 4A7E 8C87 67EA 9173 8F73 E1B7 68A0.

Download and unpack the tarball.

 cd libguestfs-1.xx.yy
 ./configure
 make

DO NOT run the tests as root!  Libguestfs can be built and tested as non-root.  Running the tests as root could even be dangerous, don't do it.

To sanity check that the build worked, do:

 make quickcheck

To run the basic tests, do:

 make check

There are many more tests you can run.  See guestfs-hacking(1) for details.

DO NOT use make install!  You'll end up with conflicting versions of libguestfs installed, and this causes constant headaches for users. See the next section for how to use the ./run script instead.

Distro packagers can use:

 make INSTALLDIRS=vendor DESTDIR=[temp-build-dir] install

You can run guestfish(1), guestmount(1) and the virt tools without needing to install them by using the ./run script in the top directory.  This script works by setting several environment variables.

For example:

 ./run guestfish [usual guestfish args ...]

 ./run virt-inspector [usual virt-inspector args ...]

The ./run script adds every libguestfs binary to the $PATH, so the above examples run guestfish and virt-inspector from the build directory (not the globally installed guestfish if there is one).

You can use the script from any directory.  If you wanted to run your own libguestfs-using program, then the following command will also work:

 /path/to/libguestfs/run ./my_program [...]

You can also run the C programs under valgrind like this:

 ./run valgrind [valgrind opts...] virt-cat [virt-cat opts...]

or under gdb:

 ./run gdb --args virt-cat [virt-cat opts...]

This also works with sudo (eg. if you need root access for libvirt or to access a block device):

 sudo ./run virt-cat -d LinuxGuest /etc/passwd

To set environment variables, you can either do:

 LIBGUESTFS_HV=/my/qemu ./run guestfish

or:

 ./run env LIBGUESTFS_HV=/my/qemu guestfish

Files in the top source directory that begin with the prefix local* are ignored by git.  These files can contain local configuration or scripts that you need to build libguestfs.

I have a file called localconfigure which is a simple wrapper around configure containing local configure customizations that I need.  It looks like this:

 . localenv
 ./configure.sh \
     -C \
     --enable-werror \
     "$@"

So I can use this to build libguestfs:

 ./localconfigure && make

If there is a file in the top build directory called localenv, then it will be sourced by make.  This file can contain any local environment variables needed, eg. for skipping tests:

 # Skip this test, it is broken.
 export SKIP_TEST_BTRFS_FSCK=1

Note that localenv is included by the top Makefile (so it’s a Makefile fragment).  But if it is also sourced by your localconfigure script then it is used as a shell script.

There are many ./configure options.  Use:

 ./configure --help

to list them all.  This section covers some of the more important ones.

--disable-appliance --disable-daemon

See "Using a Prebuilt Binary Appliance" below.

--disable-erlang

--disable-gobject

--disable-golang

--disable-haskell

--disable-lua

--disable-ocaml

--disable-perl

--disable-php

--disable-python

--disable-ruby

Disable specific language bindings, even if ./configure finds all the necessary libraries are installed so that they could be compiled.

Note that disabling OCaml (bindings) or Perl will have the knock-on effect of disabling parts of the test suite and some tools.

OCaml is required to build libguestfs and this requirement cannot be removed.  Using --disable-ocaml only disables the bindings.

--disable-fuse

Disable FUSE support in the API and the guestmount(1) tool.

--disable-static

Don’t build a static linked version of the libguestfs library.

--enable-install-daemon

Normally guestfsd(8) is not installed by make install, since that wouldn't be useful (instead it is "installed" inside the supermin appliance).  However if packagers are building "libguestfs live" then they should use this option.

--enable-werror

This turns compiler warnings into errors (ie. -Werror).  Use this for development, especially when submitting patches.  It should generally not be used for production or distro builds.

--with-default-backend=libvirt

This controls the default method that libguestfs uses to run qemu (see "BACKEND" in guestfs(3)).  If not specified, the default backend is direct, which means libguestfs runs qemu directly.

Fedora and Red Hat Enterprise Linux (RHEL) ≥ 7 use this flag to change the default backend to libvirt, because (especially in RHEL) the policy is not to allow any program to run qemu except via libvirt.

Note that despite this setting, all backends are built into libguestfs, and you can override the backend at runtime by setting the $LIBGUESTFS_BACKEND environment variable (or using API methods).

--with-distro=REDHAT|DEBIAN|...

Libguestfs needs to know which Linux distro is in use so it can choose package names for the appliance correctly (see for example appliance/packagelist.in).  It normally does this automatically.

However if you can building or packaging libguestfs on a new distro then you can use --with-distro to specify that the distro is similar to an existing one (eg. --with-distro=REDHAT if the distro is a new Red Hat or CentOS derivative).

Note that if your distro is completely new then it may still require upstream modifications.

--with-extra="distroname=version,libvirt,..."

--with-extra="local"

This option controls the "extra" field returned by "guestfs_version" in guestfs(3) and also printed by virt tools' --version option.  It is a free text field, but a good idea is to encode a comma-separated list of facts such as the distro name and version, whether libvirt is the default backend, and anything else that may help with debugging problems raised by users.

For custom and/or local builds, this can be set to local to indicate this is not a distro build.

--without-libvirt

Compile libguestfs without libvirt support, even if libvirt development libraries are installed.

--with-qemu="bin1 bin2 ..."

Provide an alternate qemu binary (or list of binaries).  This can be overridden at runtime by setting the LIBGUESTFS_HV environment variable.

--with-supermin-packager-config=yum.conf

This passes the --packager-config option to supermin(1).

The most common use for this is to build the appliance using an alternate repository (instead of using the installed yum/dnf/apt/etc configuration to find and download packages).  You might need to use this if you want to build libguestfs without having a network connection.  Examples of using this can be found in the Fedora libguestfs.spec file (see "Building a Package for Fedora" below for resources).

--with-supermin-extra-options="--opt1 --opt2 ..."

Pass additional options to supermin(1).  See appliance/make.sh.in to understand precisely what this does.

PYTHON

This environment variable may be set to point to a python binary (eg. python3).  When ./configure runs, it inspects this python binary to find the version of Python, the location of Python libraries and so on.

SUPERMIN

This environment variable can be set to choose an alternative supermin(1) binary.  This might be used, for example, if you want to use a newer upstream version of supermin than is packaged for your distro, or if supermin is not packaged at all.  On RHEL 7, you must set SUPERMIN=/usr/bin/supermin5 when compiling libguestfs.

A common problem is with broken or incompatible qemu releases.

Different versions of qemu have problems booting the appliance for different reasons.  This varies between versions of qemu, and Linux distributions which add their own patches.

If you find a problem, you could try using your own qemu built from source (qemu is very easy to build from source), with a "qemu wrapper".  See "QEMU WRAPPERS" in guestfs(3).

By default the configure script will look for qemu-kvm (KVM support). KVM is much faster than using plain qemu.

You may also need to enable KVM support for non-root users, by following these instructions: http://www.linux-kvm.org/page/FAQ#How_can_I_use_kvm_with_a_non-privileged_user.3F

On some systems, this will work too:

 chmod 0666 /dev/kvm

On some systems, the chmod will not survive a reboot, and you will need to make edits to the udev configuration.

 export CC=clang
 ./configure
 make

To understand what the libguestfs appliance means, see guestfs-internals(1).

If you are using non-Linux, or a Linux distribution that does not have supermin(1) support, or simply if you don't want to build your own libguestfs appliance, then you can use one of the prebuilt binary appliances that we supply: http://libguestfs.org/download/binaries/appliance

Build libguestfs like this:

 ./configure --disable-appliance --disable-daemon
 make

Set $LIBGUESTFS_PATH to the path where you unpacked the appliance tarball, eg:

 export LIBGUESTFS_PATH=/usr/local/lib/guestfs/appliance

and run the libguestfs programs and virt tools in the normal way, eg. using the ./run script (see above).

The Fedora spec file is stored under: http://pkgs.fedoraproject.org/cgit/rpms/libguestfs.git/

Libguestfs is built in Fedora using the ordinary Fedora build system (Koji).

Red Hat Enterprise Linux (RHEL) builds of libguestfs are heavily patched.  There are broadly two types of patches we apply:

• We disable many features that we do not wish to support for RHEL customers.  For example, the "libguestfs live" feature is disabled.
• We backport upstream features.

The patches we apply to RHEL releases are available publically in the upstream git repository, in a branch called rhel-x.y

For example, the RHEL 7.3 patches are available here: https://github.com/libguestfs/libguestfs/commits/rhel-7.3

The sources and spec files for RHEL versions of libguestfs are available on https://git.centos.org/project/rpms, and see also https://wiki.centos.org/Sources.

guestfs(3), guestfs-examples(3), guestfs-hacking(1), guestfs-internals(1), guestfs-performance(1), guestfs-release-notes(1), guestfs-testing(1), libguestfs-test-tool(1), libguestfs-make-fixed-appliance(1), http://libguestfs.org/.

Richard W.M. Jones (rjones at redhat dot com)

Copyright (C) 2009-2023 Red Hat Inc.

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

This library 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; 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: https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools

To report a new bug against libguestfs, use this link: https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools

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.

guestfs(3), guestfs-hacking(1), guestfs-release-notes-1.34(1).