Provided by: libguestfs-tools_1.36.13-1ubuntu3.3_amd64 bug


       virt-rescue - Run a rescue shell on a virtual machine


        virt-rescue [--options] -d domname

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

        virt-rescue --suggest (-d domname | -a disk.img ...)

       Old style:

        virt-rescue [--options] domname

        virt-rescue [--options] disk.img [disk.img ...]


       Using "virt-rescue" in write mode on live virtual machines, or concurrently with other
       disk editing tools, can be dangerous, potentially causing disk corruption.  The virtual
       machine must be shut down before you use this command, and disk images must not be edited

       Use the --ro (read-only) option to use "virt-rescue" safely if the disk image or virtual
       machine might be live.  You may see strange or inconsistent results if running
       concurrently with other changes, but with this option you won't risk disk corruption.


       virt-rescue is like a Rescue CD, but for virtual machines, and without the need for a CD.
       virt-rescue gives you a rescue shell and some simple recovery tools which you can use to
       examine or rescue a virtual machine or disk image.

       You can run virt-rescue on any virtual machine known to libvirt, or directly on disk

        virt-rescue -d GuestName

        virt-rescue --ro -a /path/to/disk.img

        virt-rescue -a /dev/sdc

       For live VMs you must use the --ro option.

       When you run virt-rescue on a virtual machine or disk image, you are placed in an
       interactive bash shell where you can use many ordinary Linux commands.  What you see in /
       (/bin, /lib etc) is the rescue appliance.  You must mount the virtual machine's
       filesystems by hand.  There is an empty directory called /sysroot where you can mount

       You can get virt-rescue to suggest mount commands for you by using the --suggest option
       (in another terminal):

        $ virt-rescue --suggest -d Fedora15
        Inspecting the virtual machine or disk image ...

        This disk contains one or more operating systems.  You can use these
        mount commands in virt-rescue (at the ><rescue> prompt) to mount the

        # /dev/vg_f15x32/lv_root is the root of a linux operating system
        # type: linux, distro: fedora, version: 15.0
        # Fedora release 15 (Lovelock)

        mount /dev/vg_f15x32/lv_root /sysroot/
        mount /dev/vda1 /sysroot/boot
        mount --bind /dev /sysroot/dev
        mount --bind /dev/pts /sysroot/dev/pts
        mount --bind /proc /sysroot/proc
        mount --bind /sys /sysroot/sys

       Another way is to list the logical volumes (with lvs(8)) and partitions (with parted(8))
       and mount them by hand:

        ><rescue> lvs
        LV      VG        Attr   LSize   Origin Snap%  Move Log Copy%  Convert
        lv_root vg_f15x32 -wi-a-   8.83G
        lv_swap vg_f15x32 -wi-a- 992.00M
        ><rescue> mount /dev/vg_f15x32/lv_root /sysroot
        ><rescue> mount /dev/vda1 /sysroot/boot
        ><rescue> ls /sysroot

       Another command to list available filesystems is virt-filesystems(1).

       To run commands in a Linux guest (for example, grub), you should chroot into the /sysroot
       directory first:

        ><rescue> chroot /sysroot

       Virt-rescue can be used on any disk image file or device, not just a virtual machine.  For
       example you can use it on a blank file if you want to partition that file (although we
       would recommend using guestfish(1) instead as it is more suitable for this purpose).  You
       can even use virt-rescue on things like SD cards.

       You can get virt-rescue to give you scratch disk(s) to play with.  This is useful for
       testing out Linux utilities (see --scratch).

       Virt-rescue does not require root.  You only need to run it as root if you need root to
       open the disk image.

       This tool is just designed for quick interactive hacking on a virtual machine.  For more
       structured access to a virtual machine disk image, you should use guestfs(3).  To get a
       structured shell that you can use to make scripted changes to guests, use guestfish(1).


           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

           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).

       --append KERNELOPTS
           Pass additional options to the rescue kernel.

       -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

           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-rescue --format=raw -a disk.img

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

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

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

           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).

       -m MB
       --memsize MB
           Change the amount of memory allocated to the rescue system.  The default is set by
           libguestfs and is small but adequate for running system tools.  The occasional program
           might need more memory.  The parameter is specified in megabytes.

           Enable QEMU user networking in the guest.  See "NETWORK".

           Open the image read-only.

           The option must always be used if the disk image or virtual machine might be running,
           and is generally recommended in cases where you don't need write access to the disk.

           See also "OPENING DISKS FOR READ AND WRITE" in guestfish(1).

           The --scratch option adds a large scratch disk to the rescue appliance.  --scratch=N
           adds "N" scratch disks.  The scratch disk(s) are deleted automatically when virt-
           rescue exits.

           You can also mix -a, -d and --scratch options.  The scratch disk(s) are added to the
           appliance in the order they appear on the command line.

           This option is provided for backwards compatibility and does nothing.

       --smp N
           Enable N ≥ 2 virtual CPUs in the rescue appliance.

           Inspect the disk image and suggest what mount commands should be used to mount the
           disks.  You should use the --suggest option in a second terminal, then paste the
           commands into another virt-rescue.

           This option implies --ro and is safe to use even if the guest is up or if another
           virt-rescue is running.

           Enable verbose messages for debugging.

           Display version number and exit.

           This changes the -a and -d options so that disks are added and mounts are done read-

           See "OPENING DISKS FOR READ AND WRITE" in guestfish(1).

       -x  Enable tracing of libguestfs API calls.


       Previous versions of virt-rescue allowed you to write either:

        virt-rescue disk.img [disk.img ...]


        virt-rescue 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.


       Adding the --network option enables QEMU user networking in the rescue appliance.  There
       are some differences between user networking and ordinary networking:

       ping does not work
           Because the ICMP ECHO_REQUEST protocol generally requires root in order to send the
           ping packets, and because virt-rescue must be able to run as non-root, QEMU user
           networking is not able to emulate the ping(8) command.  The ping command will appear
           to resolve addresses but will not be able to send or receive any packets.  This does
           not mean that the network is not working.

       cannot receive connections
           QEMU user networking cannot receive incoming connections.

       making TCP connections
           The virt-rescue appliance needs to be small and so does not include many network
           tools.  In particular there is no telnet(1) command.  You can make TCP connections
           from the shell using the magical /dev/tcp/<hostname>/<port> syntax:

            exec 3<>/dev/tcp/
            echo "GET /" >&3
            cat <&3

           See bash(1) for more details.


       If you are testing a tool inside virt-rescue and the tool (not virt-rescue) segfaults, it
       can be tricky to capture the core dump outside virt-rescue for later analysis.  This
       section describes one way to do this.

       1.  Create a scratch disk for core dumps:

            truncate -s 4G /tmp/corefiles
            virt-format --partition=mbr --filesystem=ext2 -a /tmp/corefiles
            virt-filesystems -a /tmp/corefiles --all --long -h

       2.  When starting virt-rescue, attach the core files disk last:

            virt-rescue --rw [-a ...] -a /tmp/corefiles

           NB. If you use the --ro option, then virt-rescue will silently not write any core
           files to /tmp/corefiles.

       3.  Inside virt-rescue, mount the core files disk.  Note replace /dev/sdb1 with the last
           disk index.  For example if the core files disk is the last of four disks, you would
           use /dev/sdd1.

            ><rescue> mkdir /tmp/mnt
            ><rescue> mount /dev/sdb1 /tmp/mnt

       4.  Enable core dumps in the rescue kernel:

            ><rescue> echo '/tmp/mnt/core.%p' > /proc/sys/kernel/core_pattern
            ><rescue> ulimit -Hc unlimited
            ><rescue> ulimit -Sc unlimited

       5.  Run the tool that caused the core dump.  The core dump will be written to

            ><rescue> ls -l /tmp/mnt
            total 1628
            -rw------- 1 root root 1941504 Dec  7 13:13 core.130
            drwx------ 2 root root   16384 Dec  7 13:00 lost+found

       6.  Before exiting virt-rescue, unmount (or at least sync) the disks:

            ><rescue> umount /tmp/mnt
            ><rescue> exit

       7.  Outside virt-rescue, the core dump(s) can be removed from the disk using guestfish(1).
           For example:

            guestfish --ro -a /tmp/corefiles -m /dev/sda1
            ><fs> ll /
            ><fs> download /core.NNN /tmp/core.NNN


       Several environment variables affect virt-rescue.  See "ENVIRONMENT VARIABLES" in
       guestfs(3) for the complete list.


           This configuration file controls the default read-only or read-write mode (--ro or

           See libguestfs-tools.conf(5).


       guestfs(3), guestfish(1), virt-cat(1), virt-edit(1), virt-filesystems(1),


       Richard W.M. Jones


       Copyright (C) 2009-2017 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