virt-diff - Differences between files in two virtual machines
virt-diff [--options] -d domain1 -D domain2
virt-diff [--options] -a disk1.img [-a ...] -A disk2.img [-A ...]
"virt-diff" lists the differences between files in two virtual
machines or disk images. The usual use case is to show the changes in a VM
after it has been running for a while, by taking a snapshot, running the VM,
and then using this tool to show what changed between the new VM state and the
old snapshot.
This tool will find differences in filenames, file sizes, checksums, extended
attributes, file content and more from a virtual machine or disk image.
However it
does not look at the boot loader, unused space between
partitions or within filesystems, "hidden" sectors and so on. In
other words, it is not a security or forensics tool.
To specify two guests, you have to use the
-a or
-d option(s) for
the first guest, and the
-A or
-D option(s) for the second
guest. The common case is:
virt-diff -a old.img -A new.img
or using names known to libvirt:
virt-diff -d oldguest -D newguest
- --help
- 簡単なヘルプを表示します。
-
-a file
-
--add file
- Add file which should be a disk image from the first
virtual machine. If the virtual machine has multiple block devices, you
must supply all of them with separate -a options.
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。
-
-a URI
-
--add URI
- リモートディスクを追加します。
"リモートストレージの追加"
in guestfish(1) 参照。
- --all
- Same as --extra-stats --times --uids
--xattrs.
- --atime
- The default is to ignore changes in file access times,
since those are unlikely to be interesting. Using this flag shows atime
differences as well.
-
-A file
-
-A URI
- Add a disk image from the second virtual machine.
- --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).
- --checksum
- --checksum=crc|md5|sha1|sha224|sha256|sha384|sha512
- Use a checksum over file contents to detect when regular
files have changed content.
With no argument, this defaults to using md5. Using an argument, you
can select the checksum type to use. If the flag is omitted then file
times and size are used to determine if a file has changed.
-
-c URI
-
--connect URI
- libvirt
を使用していると、指定された
URI に接続します。
省略すると、デフォルトの
libvirt
ハイパーバイザーに接続します。
ゲストのブロックデバイスを直接指定していると（(
-a)）、libvirt
は何も使用されません。
- --csv
- Write out the results in CSV format (comma-separated
values). This format can be imported easily into databases and
spreadsheets, but read "NOTE ABOUT CSV FORMAT" below.
- --dir-links
- The default is to ignore changes in the number of links in
directory entries, since those are unlikely to be interesting. Using this
flag shows changes to the nlink field of directories.
- --dir-times
- The default is to ignore changed times on directory
entries, since those are unlikely to be interesting. Using this flag shows
changes to the time fields of directories.
-
-d guest
-
--domain guest
- Add all the disks from the named libvirt guest, as the
first guest. Domain UUIDs can be used instead of names.
-
-D guest
- Add all the disks from the named libvirt guest, as the
second guest. Domain UUIDs can be used instead of names.
- --echo-keys
- When prompting for keys and passphrases, virt-diff 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.
- --extra-stats
- Display extra stats.
- --format=raw|qcow2|..
- --format
- The default for the -a/-A option is to
auto-detect the format of the disk image. Using this forces the disk
format for -a/-A options which follow on the command line.
Using --format with no argument switches back to auto-detection for
subsequent -a/-A options.
例:
virt-diff --format=raw -a disk.img [...]
forces raw format (no auto-detection) for disk.img.
virt-diff --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.
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)。
- -h
- --human-readable
- 読みやすい形式でファイル容量を表示します。
-
--key SELECTOR
- Specify a key for LUKS, to automatically open a LUKS device
when using the inspection. "ID" can be either the libguestfs
device name, or the UUID of the LUKS device.
-
--key "ID":key:KEY_STRING
- Use the specified "KEY_STRING" as
passphrase.
-
--key "ID":file:FILENAME
- Read the passphrase from FILENAME.
- --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.
- --times
- 時間の項目を表示します。
- --time-days
- Display time fields as days before now (negative if in the
future).
Note that 0 in output means "up to 1 day before now", or that the
age of the file is between 0 and 86399 seconds.
- --time-relative
- Display time fields as seconds before now (negative if in
the future).
- --time-t
- Display time fields as seconds since the Unix epoch.
- --uids
- UID と GID
の項目を表示します。
- -v
- --verbose
- デバッグ用の冗長なメッセージを有効にします。
- -V
- --version
- バージョン番号を表示して、終了します。
- -x
- libguestfs API
呼び出しのトレースを有効にします。
- --xattrs
- Display extended attributes.
Comma-separated values (CSV) is a deceptive format. It
seems like it
should be easy to parse, but it is definitely not easy to parse.
神話:
ただコンマで項目を区切る。
真実:
これは正しく動き
ません。この例は 2
つの列があります:
"foo,bar",baz
神話:
同時にファイルの 1
行を読み込みます。
真実:
これは正しく動き
ません。この例は 1
つの行があります:
"foo
bar",baz
For shell scripts, use "csvtool" (
https://github.com/Chris00/ocaml-csv
also packaged in major Linux distributions).
For other languages, use a CSV processing library (eg. "Text::CSV" for
Perl or Python’s built-in csv library).
Most spreadsheets and databases can import CSV directly.
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。
guestfs(3),
guestfish(1),
virt-cat(1),
virt-copy-out(1),
virt-ls(1),
virt-tar-out(1),
http://libguestfs.org/.
Richard W.M. Jones
http://people.redhat.com/~rjones/
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:
- •
- 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.