Ubuntu Manpage: virt-log - Display log files from a virtual machine

Provided by: guestfs-tools_1.52.2-2ubuntu1_amd64

NAME

       virt-log - Display log files from a virtual machine

SYNOPSIS

        virt-log [--options] -d domname

        virt-log [--options] -a disk.img [-a disk.img ...]

DESCRIPTION

       "virt-log" is a command line tool to display the log files from the named virtual machine
       (or disk image).

       This tool understands and displays both plain text log files (eg. /var/log/messages) and
       binary formats such as the systemd journal.

       To display other types of files, use virt-cat(1).  To follow (tail) text log files, use
       virt-tail(1).  To copy files out of a virtual machine, use virt-copy-out(1).  To display
       the contents of the Windows Registry, use virt-win-reg(1).

EXAMPLES

       Display the complete logs from a guest:

        virt-log -d mydomain | less

       Find out what DHCP IP address a VM acquired:

        virt-log -d mydomain | grep 'dhclient.*bound to'

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.

-a URI
--add URI
Add a remote disk. See "ADDING REMOTE STORAGE" in guestfish(1).

--blocksize=512
--blocksize=4096
--blocksize
This parameter sets the sector size of the disk image. It affects all explicitly
added subsequent disks after this parameter. Using --blocksize with no argument
switches the disk sector size to the default value which is usually 512 bytes. See
also "guestfs_add_drive_opts" in guestfs(3).

-c URI
--connect URI
If using libvirt, connect to the given URI. If omitted, then we connect to the
default libvirt hypervisor.

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-log 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
The default for the -a option is to auto-detect the format of the disk image. Using
this forces the disk format for -a options which follow on the command line. Using
--format with no argument switches back to auto-detection for subsequent -a options.

For example:

virt-log --format=raw -a disk.img

forces raw format (no auto-detection) for disk.img.

virt-log --format=raw -a disk.img --format -a another.img

forces raw format (no auto-detection) for disk.img and reverts to auto-detection for
another.img.

If you have untrusted raw-format guest disk images, you should use this option to
specify the disk format. This avoids a possible security problem with malicious
guests (CVE-2010-3851).

--key SELECTOR
Specify a key for LUKS, to automatically open a LUKS device when using the inspection.

--key NAME:key:KEY_STRING
--key UUID:key:KEY_STRING
--key all:key:KEY_STRING
"NAME" is the libguestfs device name (eg. "/dev/sda1"). "UUID" is the device
UUID. "all" means try the key against any encrypted device.

Use the specified "KEY_STRING" as passphrase.

--key NAME:file:FILENAME
--key UUID:file:FILENAME
--key all:file:FILENAME
Read the passphrase from FILENAME.

--key NAME:clevis
--key UUID:clevis
--key all:clevis
Attempt passphrase-less unlocking for the device with Clevis, over the network.
Please refer to "ENCRYPTED DISKS" in guestfs(3) for more information on network-
bound disk encryption (NBDE).

Note that if any such option is present on the command line, QEMU user networking
will be automatically enabled for the libguestfs appliance.

--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.

If there are multiple encrypted devices then you may need to supply multiple keys on
stdin, one per line.

-v
--verbose
Enable verbose messages for debugging.

-V
--version
Display version number and exit.

-x Enable tracing of libguestfs API calls.

EXIT STATUS

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

AUTHOR

       Richard W.M. Jones http://people.redhat.com/~rjones/

COPYRIGHT

       Copyright (C) 2010-2023 Red Hat Inc.

LICENSE

       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.

BUGS

       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.