From d0afef23e54f75a521eed8c7261a533776242cfc Mon Sep 17 00:00:00 2001 From: Richard Jones Date: Sat, 8 May 2010 19:55:27 +0100 Subject: [PATCH] virt-rescue: Refresh documentation. --- tools/virt-rescue | 57 +++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 45 insertions(+), 12 deletions(-) diff --git a/tools/virt-rescue b/tools/virt-rescue index aef9b82..dadb2a2 100755 --- a/tools/virt-rescue +++ b/tools/virt-rescue @@ -44,20 +44,36 @@ will probably result in disk corruption in the VM. C tries to stop you from doing this, but doesn't catch all cases. However if you use the I<--ro> (read only) option, then you can attach -a shell to a live virtual machine, but the results might be strange or -inconsistent at times (but you won't get disk corruption). +a shell to a live virtual machine. The results might be strange or +inconsistent at times but you won't get disk corruption. =head1 DESCRIPTION -virt-rescue gives you a rescue shell and some simple recovery tools -which you can use on a virtual machine disk image. +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. -After running virt-rescue, what you see under C is the recovery -appliance. +You can run virt-rescue on any virtual machine known to libvirt, or +directly on disk image(s): -You must mount the virtual machine's filesystems by hand. There -is a directory C where you can mount filesystems. For -example: + virt-rescue GuestName + + virt-rescue --ro /path/to/disk.img + + virt-rescue /dev/sdc + +For live VMs you I 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 C (C, C etc) is the +rescue appliance. You must mount the virtual machine's filesystems by +hand. There is an empty directory called C where you can +mount filesystems. + +In the example below, we list logical volumes, then choose one to +mount under C: > lvs LV VG Attr LSize Origin Snap% Move Log Copy% Convert @@ -66,10 +82,22 @@ example: > mount /dev/vg_f11x64/lv_root /sysroot > ls /sysroot +If you don't know what filesystems are available on the virtual +machine then you can use commands such as L and L +to find out. + +=head2 NOTES + +Virt-rescue can be used on I 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 +L instead as it is more suitable for this purpose). You +can even use virt-rescue on things like SD cards. + 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 L. To get a structured shell, use -L. +you should use L. To get a structured shell that you can +use to make scripted changes to guests, use L. =head1 OPTIONS @@ -147,6 +175,11 @@ $g->launch (); exit 0; +=head1 ENVIRONMENT VARIABLES + +Several environment variables affect virt-rescue. See +L for the complete list. + =head1 SEE ALSO L, @@ -163,7 +196,7 @@ Richard W.M. Jones L =head1 COPYRIGHT -Copyright (C) 2009 Red Hat Inc. +Copyright (C) 2009-2010 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 -- 1.8.3.1