NAME¶
virt-inspector - Display operating system version and other information about a
virtual machine
SYNOPSIS¶
virt-inspector [--options] -d domname
virt-inspector [--options] -a disk.img [-a disk.img ...]
Old-style:
virt-inspector domname
virt-inspector disk.img [disk.img ...]
DESCRIPTION¶
virt-inspector examines a virtual machine or disk image and tries to
determine the version of the operating system and other information about the
virtual machine.
Virt-inspector produces XML output for feeding into other programs.
In the normal usage, use "virt-inspector -d domname" where
"domname" is the libvirt domain (see: "virsh list --all").
You can also run virt-inspector directly on disk images from a single virtual
machine. Use "virt-inspector -a disk.img". In rare cases a domain
has several block devices, in which case you should list several
-a
options one after another, with the first corresponding to the guest's
"/dev/sda", the second to the guest's "/dev/sdb" and so
on.
You can also run virt-inspector on install disks, live CDs, bootable USB keys
and similar.
Virt-inspector can only inspect and report upon
one domain at a
time. To inspect several virtual machines, you have to run
virt-inspector several times (for example, from a shell script for-loop).
Because virt-inspector needs direct access to guest images, it won't normally
work over remote libvirt connections.
All of the information available from virt-inspector is also available through
the core libguestfs inspection API (see "INSPECTION" in
guestfs(3)). The same information can also be fetched using guestfish
or via libguestfs bindings in many programming languages (see "GETTING
INSPECTION DATA FROM THE LIBGUESTFS API").
OPTIONS¶
- --help
- Display brief help.
- -a file
- --add file
- Add file which should be a disk image from a virtual
machine. If the virtual machine has multiple block devices, you must
supply all of them with separate -a options.
The format of the disk image is auto-detected. To override this and force a
particular format use the --format=.. option.
- -c URI
- --connect URI
- If using libvirt, connect to the given URI. If
omitted, then we connect to the default libvirt hypervisor.
Libvirt is only used if you specify a "domname" on the command
line. If you specify guest block devices directly ( -a), then
libvirt is not used at all.
- -d guest
- --domain guest
- Add all the disks from the named libvirt guest. Domain
UUIDs can be used instead of names.
- --echo-keys
- When prompting for keys and passphrases, virt-inspector
normally turns echoing off so you cannot see what you are typing. If you
are not worried about Tempest attacks and there is no one else in the room
you can specify this flag to see what you are typing.
- --format=raw|qcow2|..
- --format
- Specify the format of disk images given on the command
line. If this is omitted then the format is autodetected from the content
of the disk image.
If disk images are requested from libvirt, then this program asks libvirt
for this information. In this case, the value of the format parameter is
ignored.
If working with untrusted raw-format guest disk images, you should ensure
the format is always specified.
- --keys-from-stdin
- Read key or passphrase parameters from stdin. The default
is to try to read passphrases from the user by opening
"/dev/tty".
- -v
- --verbose
- Enable verbose messages for debugging.
- -V
- --version
- Display version number and exit.
- -x
- Enable tracing of libguestfs API calls.
- --xpath query
- Perform an XPath query on the XML on stdin, and print the
result on stdout. In this mode virt-inspector simply runs an XPath query;
all other inspection functions are disabled. See "XPATH QUERIES"
below for some examples.
OLD-STYLE COMMAND LINE ARGUMENTS¶
Previous versions of virt-inspector allowed you to write either:
virt-inspector disk.img [disk.img ...]
or
virt-inspector guestname
whereas in this version you should use
-a or
-d respectively to
avoid the confusing case where a disk image might have the same name as a
guest.
For compatibility the old style is still supported.
The virt-inspector XML is described precisely in a RELAX NG schema file
"virt-inspector.rng" which is supplied with libguestfs. This section
is just an overview.
The top-level element is <operatingsystems>, and it contains one or more
<operatingsystem> elements. You would only see more than one
<operatingsystem> element if the virtual machine is multi-boot, which is
vanishingly rare in real world VMs.
<operatingsystem>¶
In the <operatingsystem> tag are various optional fields that describe the
operating system, its architecture, the descriptive "product name"
string, the type of OS and so on, as in this example:
<operatingsystems>
<operatingsystem>
<root>/dev/sda2</root>
<name>windows</name>
<arch>i386</arch>
<distro>windows</distro>
<product_name>Windows 7 Enterprise</product_name>
<product_variant>Client</product_variant>
<major_version>6</major_version>
<minor_version>1</minor_version>
<windows_systemroot>/Windows</windows_systemroot>
<format>installed</format>
In brief, <name> is the class of operating system (something like
"linux" or "windows"), <distro> is the distribution
(eg. "fedora" but many other distros are recognized) and
<arch> is the guest architecture. The other fields are fairly
self-explanatory, but because these fields are taken directly from the
libguestfs inspection API you can find precise information from
"INSPECTION" in
guestfs(3).
The <root> element is the root filesystem device, but from the point of
view of libguestfs (block devices may have completely different names inside
the VM itself).
<mountpoints>¶
Un*x-like guests typically have multiple filesystems which are mounted at
various mountpoints, and these are described in the <mountpoints>
element which looks like this:
<operatingsystems>
<operatingsystem>
...
<mountpoints>
<mountpoint dev="/dev/vg_f13x64/lv_root">/</mountpoint>
<mountpoint dev="/dev/sda1">/boot</mountpoint>
</mountpoints>
As with <root>, devices are from the point of view of libguestfs, and may
have completely different names inside the guest. Only mountable filesystems
appear in this list, not things like swap devices.
<filesystems>¶
<filesystems> is like <mountpoints> but covers
all
filesystems belonging to the guest, including swap and empty partitions. (In
the rare case of a multi-boot guest, it covers filesystems belonging to this
OS or shared with this OS and other OSes).
You might see something like this:
<operatingsystems>
<operatingsystem>
...
<filesystems>
<filesystem dev="/dev/vg_f13x64/lv_root">
<type>ext4</type>
<label>Fedora-13-x86_64</label>
<uuid>e6a4db1e-15c2-477b-ac2a-699181c396aa</uuid>
</filesystem>
The optional elements within <filesystem> are the filesystem type, the
label, and the UUID.
<applications>¶
The related elements <package_format>, <package_management> and
<applications> describe applications installed in the virtual machine.
<package_format>, if present, describes the packaging system used. Typical
values would be "rpm" and "deb".
<package_management>, if present, describes the package manager. Typical
values include "yum", "up2date" and "apt"
<applications> lists the packages or applications installed.
<operatingsystems>
<operatingsystem>
...
<applications>
<application>
<name>coreutils</name>
<version>8.5</version>
<release>1</release>
</application>
The version and release fields may not be available for some types guests. Other
fields are possible, see "guestfs_inspect_list_applications" in
guestfs(3).
<drive_mappings>¶
For operating systems like Windows which use drive letters, virt-inspector is
able to find out how drive letters map to filesystems.
<operatingsystems>
<operatingsystem>
...
<drive_mappings>
<drive_mapping name="C">/dev/sda2</drive_mapping>
<drive_mapping name="E">/dev/sdb1</drive_mapping>
</drive_mappings>
In the example above, drive C maps to the filesystem on the second partition on
the first disk, and drive E maps to the filesystem on the first partition on
the second disk.
Note that this only covers permanent local filesystem mappings, not things like
network shares. Furthermore NTFS volume mount points may not be listed here.
<icon>¶
Virt-inspector is sometimes able to extract an icon or logo for the guest. The
icon is returned as base64-encoded PNG data. Note that the icon can be very
large and high quality.
<operatingsystems>
<operatingsystem>
...
<icon>
iVBORw0KGgoAAAANSUhEUgAAAGAAAABg[.......]
[... many lines of base64 data ...]
</icon>
To display the icon, you have to extract it and convert the base64 data back to
a binary file. Use an XPath query or simply an editor to extract the data,
then use the coreutils
base64(1) program to do the conversion back to a
PNG file:
base64 -i -d < icon.data > icon.png
INSPECTING INSTALL DISKS, LIVE CDs¶
Virt-inspector can detect some operating system installers on install disks,
live CDs, bootable USB keys and more.
In this case the <format> tag will contain "installer" and other
fields may be present to indicate a live CD, network installer, or one part of
a multipart CD. For example:
<operatingsystems>
<operatingsystem>
<root>/dev/sda</root>
<name>linux</name>
<arch>i386</arch>
<distro>ubuntu</distro>
<product_name>Ubuntu 10.10 "Maverick Meerkat"</product_name>
<major_version>10</major_version>
<minor_version>10</minor_version>
<format>installer</format>
<live/>
XPATH QUERIES¶
Virt-inspector includes built in support for running XPath queries. The reason
for including XPath support directly in virt-inspector is simply that there
are no good and widely available command line programs that can do XPath
queries. The only good one is
xmlstarlet(1) and that is not available
on Red Hat Enterprise Linux.
To perform an XPath query, use the
--xpath option. Note that in this
mode, virt-inspector simply reads XML from stdin and outputs the query result
on stdout. All other inspection features are disabled in this mode.
For example:
$ virt-inspector -d Guest | virt-inspector --xpath '//filesystems'
<filesystems>
<filesystem dev="/dev/vg_f13x64/lv_root">
<type>ext4</type>
[...]
$ virt-inspector -d Guest | \
virt-inspector --xpath "string(//filesystem[@dev='/dev/sda1']/type)"
ext4
$ virt-inspector -d Guest | \
virt-inspector --xpath 'string(//icon)' | base64 -i -d | display -
[displays the guest icon, if there is one]
SHELL QUOTING¶
Libvirt guest names can contain arbitrary characters, some of which have meaning
to the shell such as "#" and space. You may need to quote or escape
these characters on the command line. See the shell manual page
sh(1)
for details.
GETTING INSPECTION DATA FROM THE LIBGUESTFS API¶
In early versions of libguestfs, virt-inspector was a large Perl script that
contained many heuristics for inspecting guests. This had several problems: in
order to do inspection from other tools (like guestfish) we had to call out to
this Perl script; and it privileged Perl over other languages that libguestfs
supports.
By libguestfs 1.8 we had rewritten the Perl code in C, and incorporated it all
into the core libguestfs API (
guestfs(3)). Now virt-inspector is
simply a thin C program over the core C API. All of the inspection information
is available from all programming languages that libguestfs supports, and from
guestfish.
For a description of the C inspection API, read "INSPECTION" in
guestfs(3).
For example code using the C inspection API, look for "inspect_vm.c"
which ships with libguestfs.
"inspect_vm.c" has also been translated into other languages. For
example, "inspect_vm.pl" is the Perl translation, and there are
other translations for OCaml, Python, etc. See "USING LIBGUESTFS WITH
OTHER PROGRAMMING LANGUAGES" in
guestfs(3) for a list of man pages
which contain this example code.
GETTING INSPECTION DATA FROM GUESTFISH¶
If you use the guestfish
-i option, then the main C inspection API
"guestfs_inspect_os" in
guestfs(3) is called. This is
equivalent to the guestfish command "inspect-os". You can also call
this guestfish command by hand.
"inspect-os" performs inspection on the current disk image, returning
the list of operating systems found. Each OS is represented by its root
filesystem device. In the majority of cases, this command prints nothing (no
OSes found), or a single root device, but beware that it can print multiple
lines if there are multiple OSes or if there is an install CD attached to the
guest.
$ guestfish --ro -a F15x32.img
><fs> run
><fs> inspect-os
/dev/vg_f15x32/lv_root
Using the root device, you can fetch further information about the guest:
><fs> inspect-get-type /dev/vg_f15x32/lv_root
linux
><fs> inspect-get-distro /dev/vg_f15x32/lv_root
fedora
><fs> inspect-get-major-version /dev/vg_f15x32/lv_root
15
><fs> inspect-get-product-name /dev/vg_f15x32/lv_root
Fedora release 15 (Lovelock)
Limitations of guestfish make it hard to assign the root device to a variable
(since guestfish doesn't have variables), so if you want to do this
reproducibly you are better off writing a script using one of the other
languages that the libguestfs API supports.
To list applications, you have to first mount up the disks:
><fs> inspect-get-mountpoints /dev/vg_f15x32/lv_root
/: /dev/vg_f15x32/lv_root
/boot: /dev/vda1
><fs> mount-ro /dev/vg_f15x32/lv_root /
><fs> mount-ro /dev/vda1 /boot
and then call the inspect-list-applications API:
><fs> inspect-list-applications /dev/vg_f15x32/lv_root | head -28
[0] = {
app_name: ConsoleKit
app_display_name:
app_epoch: 0
app_version: 0.4.5
app_release: 1.fc15
app_install_path:
app_trans_path:
app_publisher:
app_url:
app_source_package:
app_summary:
app_description:
}
[1] = {
app_name: ConsoleKit-libs
app_display_name:
app_epoch: 0
app_version: 0.4.5
app_release: 1.fc15
app_install_path:
app_trans_path:
app_publisher:
app_url:
app_source_package:
app_summary:
app_description:
}
To display an icon for the guest, note that filesystems must also be mounted as
above. You can then do:
><fs> inspect-get-icon /dev/vg_f15x32/lv_root | display -
OLD VERSIONS OF VIRT-INSPECTOR¶
As described above, early versions of libguestfs shipped with a different
virt-inspector program written in Perl (the current version is written in C).
The XML output of the Perl virt-inspector was different and it could also
output in other formats like text.
The old virt-inspector is no longer supported or shipped with libguestfs.
To confuse matters further, in Red Hat Enterprise Linux 6 we ship two versions
of virt-inspector with different names:
virt-inspector Old Perl version.
virt-inspector2 New C version.
EXIT STATUS¶
This program returns 0 if successful, or non-zero if there was an error.
SEE ALSO¶
guestfs(3),
guestfish(1), <
http://www.w3.org/TR/xpath/>,
base64(1),
xmlstarlet(1), <
http://libguestfs.org/>.
AUTHORS¶
- •
- Richard W.M. Jones
<http://people.redhat.com/~rjones/>
- •
- Matthew Booth mbooth@redhat.com
COPYRIGHT¶
Copyright (C) 2010-2012 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.
