1virt-get-kernel(1)          Virtualization Support          virt-get-kernel(1)
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NAME

6       virt-get-kernel - Extract kernel and ramdisk from guests
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SYNOPSIS

9        virt-get-kernel [--options] -d domname
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11        virt-get-kernel [--options] -a disk.img
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DESCRIPTION

14       This program extracts the kernel and initramfs from a guest.
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16       The format of the disk image is automatically detected unless you
17       specify it by using the --format option.
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19       In the case where the guest contains multiple kernels, the one with the
20       highest version number is chosen.  To extract arbitrary kernels from
21       the disk image, see guestfish(1).  To extract the entire "/boot"
22       directory of a guest, see virt-copy-out(1).
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OPTIONS

25       --help
26           Display help.
27
28       -a file
29       --add file
30           Add file which should be a disk image from a virtual machine.
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32           The format of the disk image is auto-detected.  To override this
33           and force a particular format use the --format option.
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35       -a URI
36       --add URI
37           Add a remote disk.  The URI format is compatible with guestfish.
38           See "ADDING REMOTE STORAGE" in guestfish(1).
39
40       --blocksize 512
41       --blocksize 4096
42           This parameter sets the sector size of the disk image added with -a
43           option and is ignored for libvirt guest added with -d option.  See
44           also "guestfs_add_drive_opts" in guestfs(3).
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46       --colors
47       --colours
48           Use ANSI colour sequences to colourize messages.  This is the
49           default when the output is a tty.  If the output of the program is
50           redirected to a file, ANSI colour sequences are disabled unless you
51           use this option.
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53       -c URI
54       --connect URI
55           If using libvirt, connect to the given URI.  If omitted, then we
56           connect to the default libvirt hypervisor.
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58           If you specify guest block devices directly (-a), then libvirt is
59           not used at all.
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61       -d guest
62       --domain guest
63           Add all the disks from the named libvirt guest.  Domain UUIDs can
64           be used instead of names.
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66       --echo-keys
67           When prompting for keys and passphrases, virt-get-kernel normally
68           turns echoing off so you cannot see what you are typing.  If you
69           are not worried about Tempest attacks and there is no one else in
70           the room you can specify this flag to see what you are typing.
71
72       --format raw|qcow2|..
73       --format auto
74           The default for the -a option is to auto-detect the format of the
75           disk image.  Using this forces the disk format for the -a option on
76           the command line.
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78           If you have untrusted raw-format guest disk images, you should use
79           this option to specify the disk format.  This avoids a possible
80           security problem with malicious guests (CVE-2010-3851).
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82       --key SELECTOR
83           Specify a key for LUKS, to automatically open a LUKS device when
84           using the inspection.  "ID" can be either the libguestfs device
85           name, or the UUID of the LUKS device.
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87           --key "ID":key:KEY_STRING
88               Use the specified "KEY_STRING" as passphrase.
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90           --key "ID":file:FILENAME
91               Read the passphrase from FILENAME.
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93           --key "ID":clevis
94               Attempt passphrase-less unlocking for "ID" with Clevis, over
95               the network.  Please refer to "ENCRYPTED DISKS" in guestfs(3)
96               for more information on network-bound disk encryption (NBDE).
97
98               Note that if any such option is present on the command line,
99               QEMU user networking will be automatically enabled for the
100               libguestfs appliance.
101
102       --keys-from-stdin
103           Read key or passphrase parameters from stdin.  The default is to
104           try to read passphrases from the user by opening /dev/tty.
105
106           If there are multiple encrypted devices then you may need to supply
107           multiple keys on stdin, one per line.
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109       --machine-readable
110       --machine-readable=format
111           This option is used to make the output more machine friendly when
112           being parsed by other programs.  See "MACHINE READABLE OUTPUT"
113           below.
114
115       -o directory
116       --output directory
117           This option specifies the output directory where kernel and
118           initramfs from the guest are written.
119
120           If not specified, the default output is the current directory.
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122       --prefix prefix
123           This option specifies a prefix for the extracted files.
124
125           If a prefix is specified, then there will be a dash ("-") after the
126           prefix and before the rest of the file name; for example, a kernel
127           in the guest like "vmlinuz-3.19.0-20-generic" is saved as
128           "mydistro-vmlinuz-3.19.0-20-generic" when the prefix is "mydistro".
129
130           See also --unversioned-names.
131
132       -q
133       --quiet
134           Don’t print ordinary progress messages.
135
136       --unversioned-names
137           This option affects the destination file name of extracted files.
138
139           If enabled, files will be saved locally just with the base name;
140           for example, kernel and ramdisk in the guest like
141           "vmlinuz-3.19.0-20-generic" and "initrd.img-3.19.0-20-generic" are
142           saved respectively as "vmlinuz" and "initrd.img".
143
144           See also --prefix.
145
146       -v
147       --verbose
148           Enable verbose messages for debugging.
149
150       -V
151       --version
152           Display version number and exit.
153
154       --wrap
155           Wrap error, warning, and informative messages.  This is the default
156           when the output is a tty.  If the output of the program is
157           redirected to a file, wrapping is disabled unless you use this
158           option.
159
160       -x  Enable tracing of libguestfs API calls.
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MACHINE READABLE OUTPUT

163       The --machine-readable option can be used to make the output more
164       machine friendly, which is useful when calling virt-get-kernel from
165       other programs, GUIs etc.
166
167       Use the option on its own to query the capabilities of the virt-get-
168       kernel binary.  Typical output looks like this:
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170        $ virt-get-kernel --machine-readable
171        virt-get-kernel
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173       A list of features is printed, one per line, and the program exits with
174       status 0.
175
176       It is possible to specify a format string for controlling the output;
177       see "ADVANCED MACHINE READABLE OUTPUT" in guestfs(3).
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ENVIRONMENT VARIABLES

180       For other environment variables which affect all libguestfs programs,
181       see "ENVIRONMENT VARIABLES" in guestfs(3).
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EXIT STATUS

184       This program returns 0 if successful, or non-zero if there was an
185       error.
186

SEE ALSO

188       guestfs(3), guestfish(1), guestmount(1), virt-copy-out(1),
189       virt-drivers(1), http://libguestfs.org/.
190

AUTHOR

192       Richard W.M. Jones http://people.redhat.com/~rjones/
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195       Copyright (C) 2013-2023 Red Hat Inc.
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LICENSE

198       This program is free software; you can redistribute it and/or modify it
199       under the terms of the GNU General Public License as published by the
200       Free Software Foundation; either version 2 of the License, or (at your
201       option) any later version.
202
203       This program is distributed in the hope that it will be useful, but
204       WITHOUT ANY WARRANTY; without even the implied warranty of
205       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
206       General Public License for more details.
207
208       You should have received a copy of the GNU General Public License along
209       with this program; if not, write to the Free Software Foundation, Inc.,
210       51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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BUGS

213       To get a list of bugs against libguestfs, use this link:
214       https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools
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216       To report a new bug against libguestfs, use this link:
217       https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools
218
219       When reporting a bug, please supply:
220
221       •   The version of libguestfs.
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223       •   Where you got libguestfs (eg. which Linux distro, compiled from
224           source, etc)
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226       •   Describe the bug accurately and give a way to reproduce it.
227
228       •   Run libguestfs-test-tool(1) and paste the complete, unedited output
229           into the bug report.
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233guestfs-tools-1.50.1              2023-04-06                virt-get-kernel(1)
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