| guestmount(1) | Virtualization Support | guestmount(1) |
guestmount - Mount a guest filesystem on the host using FUSE and libguestfs
guestmount [--options] -a disk.img -m device [--ro] mountpoint guestmount [--options] -a disk.img -i [--ro] mountpoint guestmount [--options] -d Guest -i [--ro] mountpoint
The guestmount program can be used to mount virtual machine filesystems and other disk images on the host. It uses libguestfs for access to the guest filesystem, and FUSE (the "filesystem in userspace") to make it appear as a mountable device.
Along with other options, you have to give at least one device (-a option) or libvirt domain (-d option), and at least one mountpoint (-m option) or use the -i inspection option. How this works is better explained in the guestfish(1) manual page, or by looking at the examples below.
FUSE lets you mount filesystems as non-root. The mountpoint must be owned by you. The filesystem will not be visible to any other users unless you make configuration changes, see "NOTES" below.
To unmount the filesystem, use the guestunmount(1) command.
For a typical Windows guest which has its main filesystem on the first partition:
guestmount -a windows.img -m /dev/sda1 --ro /mnt
For a typical Linux guest which has a /boot filesystem on the first partition, and the root filesystem on a logical volume:
guestmount -a linux.img -m /dev/VG/LV -m /dev/sda1:/boot --ro /mnt
To get libguestfs to detect guest mountpoints for you:
guestmount -a guest.img -i --ro /mnt
For a libvirt guest called "Guest" you could do:
guestmount -d Guest -i --ro /mnt
If you don’t know what filesystems are contained in a guest or disk image, use virt-filesystems(1) first:
virt-filesystems -d MyGuest
If you want to trace the libguestfs calls but without excessive debugging information, we recommend:
guestmount [...] --trace /mnt
If you want to debug the program, we recommend:
guestmount [...] --trace --verbose /mnt
To unmount the filesystem after using it:
guestunmount /mnt
If you mount a filesystem as one user (eg. root), then other users will not be able to see it by default. The fix is to add the FUSE "allow_other" option when mounting:
sudo guestmount [...] -o allow_other /mnt
and to enable this option in /etc/fuse.conf.
On some distros, you may need to add yourself to a special group (eg. "fuse") before you can use any FUSE filesystem. This is necessary on Debian and derivatives.
On other distros, no special group is required. It is not necessary on Fedora or Red Hat Enterprise Linux.
You can see this error when another process on the system jumps into the mountpoint you have just created, holding it open and preventing you from unmounting it. The usual culprits are various GUI "indexing" programs.
The popular workaround for this problem is to retry the "fusermount -u" command a few times until it works (guestunmount(1) does this for you). Unfortunately this isn't a reliable fix if (for example) the mounted filesystem is particularly large and the intruding program particularly persistent.
A proper fix is to use a private mountpoint by creating a new mount namespace using the Linux-specific clone(2)/unshare(2) flag "CLONE_NEWNS". Unfortunately at the moment this requires root and we would also probably need to add it as a feature to guestmount.
When guestunmount(1)/fusermount(1) exits, guestmount may still be running and cleaning up the mountpoint. The disk image will not be fully finalized.
This means that scripts like the following have a nasty race condition:
guestmount -a disk.img -i /mnt # copy things into /mnt guestunmount /mnt # immediately try to use 'disk.img' ** UNSAFE **
The solution is to use the --pid-file option to write the guestmount PID to a file, then after guestunmount spin waiting for this PID to exit.
guestmount -a disk.img -i --pid-file guestmount.pid /mnt
# ...
# ...
# Save the PID of guestmount *before* calling guestunmount.
pid="$(cat guestmount.pid)"
# Unmount the filesystem.
guestunmount /mnt
timeout=10
count=$timeout
while kill -0 "$pid" 2>/dev/null && [ $count -gt 0 ]; do
sleep 1
((count--))
done
if [ $count -eq 0 ]; then
echo "$0: wait for guestmount to exit failed after $timeout seconds"
exit 1
fi
# Now it is safe to use the disk image.
Note that if you use the "guestfs_mount_local" API directly (see "MOUNT LOCAL" in guestfs(3)) then it is much easier to write a safe, race-free program.
ディスクイメージの形式は自動検知されます。 これを上書きして強制的に特定の形式を使用する場合、 --format=.. オプションを使用します。
I<-d> オプションと同時に使用するとき、 これは使用する libvirt URI を指定します。 標準状態で標準の libvirt 接続を使用します。
名前の代わりに仮想マシンの UUID を使用できます。
There is also a different attribute cache implemented by FUSE (see the FUSE option -o attr_timeout), but the FUSE cache does not anticipate future requests, only cache existing ones.
仮想マシンのディスクイメージが信頼できない raw 形式である場合、 ディスク形式を指定するためにこのオプションを使用すべきです。 これにより、悪意のある仮想マシンにより起こり得る セキュリティ問題を回避できます (CVE-2010-3851)。 "guestfs(3)/guestfs_add_drive_opts" 参照。
Note that if any such option is present on the command line, QEMU user networking will be automatically enabled for the libguestfs appliance.
If there are multiple encrypted devices then you may need to supply multiple keys on stdin, one per line.
If the mountpoint is omitted, it defaults to /. You have to mount something on /.
マウントパラメーターの三番目の (ほとんど使用されない) 項目は、 バックエンドのファイルシステムをマウントするために使用される マウントオプションの一覧です。 これが指定されていない場合、 マウントオプションは空文字列または "ro" (--ro フラグが使用されている場合) になります。
-m /dev/sda1:/:acl,user_xattr
パラメーターの四番目の項目は使用するファイルシステムドライバー ("ext3" や "ntfs" など) です。 これはほとんど必要ありません。 しかし、複数のドライバーがファイルシステムに対して有効である場合 (例: "ext2" と "ext3")、 または libguestfs がファイルシステムを誤検知している場合、 これは有用です。
To get a list of all the extra options supported by FUSE, use the command below. Note that only the FUSE -o options can be passed, and only some of them are a good idea.
guestmount --fuse-help
Some potentially useful FUSE options:
Without this option, FUSE makes up its own inode numbers. The inode numbers you see in stat(2), "ls -i" etc aren't the inode numbers of the underlying filesystem.
Note this option is potentially dangerous if the underlying filesystem consists of multiple mountpoints, as you may see duplicate inode numbers appearing through FUSE. Use of this option can confuse some software.
This is highly recommended if you are not going to edit the guest disk. If the guest is running and this option is not supplied, then there is a strong risk of disk corruption in the guest. We try to prevent this from happening, but it is not always possible.
"OPENING DISKS FOR READ AND WRITE" in guestfish(1) 参照。
"OPENING DISKS FOR READ AND WRITE" in guestfish(1) 参照。
This also stops the daemon from forking into the background (see --no-fork).
このプログラムは、成功すると 0 を、エラーがあると 0 以外を返します。
guestunmount(1), fusermount(1), guestfish(1), virt-inspector(1), virt-cat(1), virt-edit(1), virt-tar(1), libguestfs-tools.conf(5), "MOUNT LOCAL" in guestfs(3), http://libguestfs.org/, http://fuse.sf.net/.
Richard W.M. Jones ("rjones at redhat dot com")
Copyright (C) 2009-2020 Red Hat Inc.
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:
| 2022-11-28 | libguestfs-1.48.6 |