NAME
- virt-df - 'df'-like utility for virtualization stats
+ virt-uname - system information for virtual machines
+
+ virt-dmesg - print kernel messages for virtual machines
SUMMARY
- virt-df [-options]
+ virt-uname [-options] [domains...]
+
+ virt-dmesg [-options] [domains...]
DESCRIPTION
- virt-df is a df(1)-like utility for showing the actual disk usage of
- guests. Many command line options are the same as for ordinary *df*.
+ These virtualization tools allow you to inspect the status of virtual
+ machines running Linux.
+
+ The tools all use libvirt so are capable of showing stats across a
+ variety of different virtualization systems.
+
+COMMON OPTIONS
+ Each command obeys a common set of options. The general form is:
- It uses libvirt so it is capable of showing stats across a variety of
- different virtualization systems.
+ virt-*program* [-options] [domains...]
-OPTIONS
- -a, --all
- Show all domains. The default is show only running (active) domains.
+ where *domains* is a list of guest names to act on. If no domains are
+ specified then we act on all active domains by default.
+
+ A *domain* may be specified either by its name or by its ID. Use *virsh
+ list* to get a list of active domain names and IDs.
+
+ The virt-mem tools do not work on domains which are not active (running
+ or paused). eg. They do not work on shut down domains.
-c uri, --connect uri
Connect to libvirt URI. The default is to connect to the default
Print the results in CSV format, suitable for importing into a
spreadsheet or database.
- This option is only supported if virt-df was built with CSV support.
+ This option is only supported if virt-mem was built with CSV
+ support.
--debug
Emit debugging information on stderr. Please supply this if you
report a bug.
- -h, --human-readable
- Display human-readable sizes (eg. "10GiB" instead of large numbers).
-
- -i, --inodes
- Display inode information.
-
- This option only works for Unix-like filesystems.
-
--help
Display usage summary.
- -t diskimage
+ -t memoryimage
Test mode. Instead of checking libvirt for domain information, this
- runs virt-df directly on the disk image (or device) supplied. You
+ runs the virt-mem tool directly on the memory image supplied. You
may specify the -t option multiple times.
--version
Display version and exit.
-EXAMPLE
- # virt-df
- Filesystem 1K-blocks Used Available Type
- f9x32kvm:hda1 190740 24817 165923 Linux ext2/3
- f9x32kvm:VolGroup/LogVol00 6568348 3401656 3166692 Linux ext2/3
- f9x32kvm:VolGroup/LogVol01 1015808 Linux swap
+ -E auto|littleendian|bigendian
+ -T auto|i386|x86-64|*address*
+ -W auto|32|64
+ These options force the endianness, text address, and word size for
+ the subsequent domains listed on the command line (or if no domains
+ are listed, then for all domains).
+
+ These default to *auto* which tries to do automatic detection (using
+ libvirt, or details from the memory images themselves). You only
+ need to use these options if virt-mem tools get the automatic
+ detection wrong.
+
+ Endianness (*-E*) sets the memory endianness, for data, pointers and
+ so on.
+
+ Text address (*-T*) sets the base address of the kernel image. *-T
+ i386* means to try some common addresses for i386-based kernels. *-T
+ x86-64* means to try some common addresses for x86-64-based kernels.
+ *-T *address** sets the address specifically (*0x* prefix is allowed
+ to specify hex addresses).
+
+ Word size (*-W*) sets the word size, 32 or 64 bits.
+
+ -A auto|i386|x86-64|...
+ This option sets the architecture to one of a collection of known
+ architectures. It is equivalent to setting endianness and wordsize
+ in one go, but not text address.
+
+EXAMPLES
+ # virt-uname
+ f9x32kvm: Linux localhost.localdomain 2.6.24-0.155.rc7.git6.fc9 #1
+ SMP Tue Jan 15 17:52:31 EST 2008 i686 (none)
+
+ # virt-dmesg f9x32kvm | tail
+ <6>Bluetooth: Core ver 2.11
+ <6>NET: Registered protocol family 31
+ <6>Bluetooth: HCI device and connection manager initialized
+ <6>Bluetooth: HCI socket layer initialized
+ <6>Bluetooth: L2CAP ver 2.9
+ <6>Bluetooth: L2CAP socket layer initialized
+ <6>Bluetooth: RFCOMM socket layer initialized
+ <6>Bluetooth: RFCOMM TTY layer initialized
+ <6>Bluetooth: RFCOMM ver 1.8
+ <7>eth0: no IPv6 routers present
SHORTCOMINGS
- virt-df spies on the guest's disk image to try to work out how much disk
- space it is actually using. There are some shortcomings to this,
- described here.
-
- (1) It only understands a limited set of partition types. Assuming that
- the files and partitions that we get back from libvirt / Xen correspond
- to block devices in the guests, we can go some way towards manually
- parsing those partitions to find out what they contain. We can read the
- MBR, LVM, superblocks and so on. However that's a lot of parsing work,
- and currently there is no library which understands a wide range of
- partition schemes and filesystem types (not even libparted which doesn't
- support LVM yet). The Linux kernel does support that, but there's not
- really any good way to access that work.
-
- The current implementation uses a hand-coded parser which understands
- some formats (MBR, LVM2, ext2/3, DOS FAT, Windows NTFS, Linux swap and
- Linux suspend partitions).
-
- (2) The statistics you get are delayed. The real state of, for example,
- an ext2 filesystem is only stored in the memory of the guest's kernel.
- The ext2 superblock contains some meta-information about blocks used and
- free, but this superblock is not up to date. In fact the guest kernel
- may not update it even on a 'sync', not until the filesystem is
- unmounted. Some operations do appear to write the superblock, for
- example fsync(2) [that is my reading of the ext2/3 source code at
- least].
+ The virt-mem tools spy on the guest's memory image. There are some
+ shortcomings to this, described here.
+
+ (1) Only works on specific, tested releases of Linux kernels. Support
+ for arbitrary Linux kernel versions may be patchy because of changes in
+ the internal structures used. Support for non-Linux kernels is currently
+ non-existent, and probably impossible for Windows because of lack of an
+ acceptable source license.
+
+ (2) Heuristics are used which may mean in the worst case that the output
+ is wrong.
+
+ (3) Structures which are frequently modified may cause errors. This
+ could be a problem if, for example, the process table in the guest is
+ being rapidly updated.
+
+ (4) We have to scan memory to find kernel symbols, etc., which can be
+ quite slow. Optimizing the memory scanner would help, and caching the
+ base address of the symbol table(s) would make it dramatically faster.
SECURITY
The current code tries hard to be secure against malicious guests, for
- example guests which set up malicious disk partitions.
+ example guests which set up malicious kernel memory.
SEE ALSO
- df(1), virsh(1), xm(1), <http://www.libvirt.org/ocaml/>,
+ uname(1), dmesg(1), virsh(1), xm(1), <http://www.libvirt.org/ocaml/>,
<http://www.libvirt.org/>, <http://et.redhat.com/~rjones/>,
<http://caml.inria.fr/>
Richard W.M. Jones <rjones @ redhat . com>
COPYRIGHT
- (C) Copyright 2007-2008 Red Hat Inc., Richard W.M. Jones
- http://libvirt.org/
+ (C) Copyright 2008 Red Hat Inc., Richard W.M. Jones http://libvirt.org/
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
Bugs can be viewed on the Red Hat Bugzilla page:
<https://bugzilla.redhat.com/>.
- If you find a bug in virt-df, please follow these steps to report it:
+ If you find a bug in virt-mem, please follow these steps to report it:
1. Check for existing bug reports
Go to <https://bugzilla.redhat.com/> and search for similar bugs.
2. Capture debug and error messages
Run
- virt-df --debug > virt-df.log 2>&1
+ virt-*program* --debug > virt-mem.log 2>&1
- and keep *virt-df.log*. It contains error messages which you should
+ and keep *virt-mem.log*. It contains error messages which you should
submit with your bug report.
- 3. Get version of virt-df and version of libvirt.
+ 3. Get version of virt-mem and version of libvirt.
Run
- virt-df --version
+ virt-*program* --version
4. Submit a bug report.
Go to <https://bugzilla.redhat.com/> and enter a new bug. Please
git.annexia.org / virt-mem.git / blobdiff