Add support for decoding the Windows registry.

[libguestfs.git] / README

diff --git a/README b/README
index 6c9d5ab..88fca7d 100644 (file)
--- a/README
+++ b/README
@@ -1,4 +1,4 @@
-libguestfs is a library for accessing and modifying guest disk images.
+Libguestfs is a library for accessing and modifying guest disk images.

 Amongst the things this is good for: making batch configuration
 changes to guests, getting disk used/free statistics (see also:
 virt-df), migrating between virtualization systems (see also:
 Amongst the things this is good for: making batch configuration
 changes to guests, getting disk used/free statistics (see also:
 virt-df), migrating between virtualization systems (see also:


@@ -6,22 +6,20 @@ virt-p2v), performing partial backups, performing partial guest
 clones, cloning guests and changing registry/UUID/hostname info, and
 much else besides.
 
 clones, cloning guests and changing registry/UUID/hostname info, and
 much else besides.
 

-libguestfs uses Linux kernel and qemu code, and can access any type of
+Libguestfs uses Linux kernel and qemu code, and can access any type of

 guest filesystem that Linux and qemu can, including but not limited
 to: ext2/3/4, btrfs, FAT and NTFS, LVM, many different disk partition
 schemes, qcow, qcow2, vmdk.
 
 guest filesystem that Linux and qemu can, including but not limited
 to: ext2/3/4, btrfs, FAT and NTFS, LVM, many different disk partition
 schemes, qcow, qcow2, vmdk.
 

-libguestfs provides ways to enumerate guest storage (eg. partitions,
+Libguestfs provides ways to enumerate guest storage (eg. partitions,

 LVs, what filesystem is in each LV, etc.).  It can also run commands
 LVs, what filesystem is in each LV, etc.).  It can also run commands

-in the context of the guest.  Also you can mount guest filesystems on
-the host (requires root privs and NFS).
+in the context of the guest.  Also you can access filesystems over FTP.

 
 

-libguestfs is a library that can be linked with C and C++ management
-programs (or management programs written in other languages, if people
-contribute the language bindings).  You can also use it from shell
-scripts or the command line.
+Libguestfs is a library that can be linked with C and C++ management
+programs (or management programs written in OCaml, Perl, Python, Ruby, Java
+or Haskell).  You can also use it from shell scripts or the command line.

 
 

-libguestfs was written by Richard W.M. Jones (rjones@redhat.com).
+Libguestfs was written by Richard W.M. Jones (rjones@redhat.com).

 For discussion please use the fedora-virt mailing list:
 
   https://www.redhat.com/mailman/listinfo/fedora-virt
 For discussion please use the fedora-virt mailing list:
 
   https://www.redhat.com/mailman/listinfo/fedora-virt


@@ -30,139 +28,192 @@ For discussion please use the fedora-virt mailing list:
 Requirements
 ----------------------------------------------------------------------
 
 Requirements
 ----------------------------------------------------------------------
 

-- nfs-utils source, unpacked
-  http://download.sourceforge.net/nfs
+- recent QEMU >= 0.10 with vmchannel support
+  http://lists.gnu.org/archive/html/qemu-devel/2009-02/msg01042.html

 
 

-- Recent QEMU with vmchannel support
+- febootstrap >= 2.0

 
 

-- Compiled Linux kernels for 32 and/or 64 bit (see note below).
+- fakeroot

 
 

-- mkinitrd
+- fakechroot >= 2.9

 
 

-- cpio
+- XDR, rpcgen (on Linux these are provided by glibc)

 
 

-- XDR, rpcgen
+- squashfs-tools (mksquashfs only)

 
 

-- If you are running a 64 bit or non-x86 machine, see note below.
+- (Optional) Augeas (http://augeas.net/)

 
 

-We don't support initramfs at the moment.  Patches gratefully
-received.
+- perldoc (pod2man, pod2text) to generate the manual pages and
+  other documentation.

 
 

-Running ./configure will check you have all the requirements installed
-on your machine.
+- (Optional) Readline to have nicer command-line editing in guestfish.

 
 

+- (Optional) 'reged' program from chntpw to decode Windows registry
+  entries (http://home.eunet.no/~pnordahl/ntpasswd/)

 
 

-Building
-----------------------------------------------------------------------
+- (Optional) OCaml if you want to rebuild the generated files, and
+  also to build the OCaml bindings

 
 

-Unpack nfs-utils source into a directory somewhere, then create a
-symlink daemon/nfs-utils to where you unpacked it.  For example:
+- (Optional) local Fedora mirror

 
 

-  pushd daemon
-  tar zxf /path/to/nfs-utils-1.1.4.tar.gz
-  ln -s nfs-utils-1.1.4 nfs-utils
-  popd
+- (Optional) Perl if you want to build the perl bindings

 
 

-For nfs-utils 1.1.4, you may find that the patch
-(nfs-utils-1.1.4-build.patch) helps.
+- (Optional) Python if you want to build the python bindings

 
 

-Then make the library and shell tools:
+- (Optional) Ruby, rake if you want to build the ruby bindings

 
 

-  ./configure
-  make
+- (Optional) Java, JNI, jpackage-utils if you want to build the java
+bindings

 
 

-Make the daemon and NFS server:
-  mkdir daemon/build
-  pushd daemon/build
-  ../configure
-  make
-  popd
+- (Optional) GHC if you want to build the Haskell bindings
+
+Running ./configure will check you have all the requirements installed
+on your machine.
+
+
+Building
+----------------------------------------------------------------------

 
 

-For 64 bit you'll probably want to build the 32 bit daemon and NFS
-server too:
+Then make the daemon, library and root filesystem:

 
 

-  mkdir daemon/build-32
-  pushd daemon/build-32
-  ../configure --enable-32bit
+  ./configure [--with-mirror=URI]

   make
   make

-  popd

 
 

-For complex cross-architecture environments, you may want to build
-other versions of the daemon and NFS server as well.  See the note
-below.
+Use the optional --with-mirror parameter to specify the URI of a local
+Fedora mirror.  See the discussion of the MIRROR parameter in the
+febootstrap(8) manpage.

 
 Finally run the tests:
 
   make check
 
 If everything works, you can install the library and tools by running
 
 Finally run the tests:
 
   make check
 
 If everything works, you can install the library and tools by running

-these commands as root:
+this command as root:

 
   make install
 
 
   make install
 

-  pushd daemon/build
-  make install
-  popd
-  # Repeat for each daemon/build* directory you made above.

 
 

+Fedora
+----------------------------------------------------------------------
+
+We provide packages for Fedora >= 11 in Fedora.  Use those, or build
+from our source RPMs - it's far simpler that way.
+
+You can compile libguestfs on Fedora 10 but you cannot use it with the
+version of qemu in Fedora 10.  You need to compile your own qemu, see
+section 'qemu' below.

 
 

-Note on 64 bit and non-x86 architectures
+
+RHEL / EPEL / CentOS etc

 ----------------------------------------------------------------------
 
 ----------------------------------------------------------------------
 

-The library runs the Linux kernel code in QEMU.  It also runs a small
-control daemon inside QEMU.  It might also run an NFS server.  It
-might also run programs from the guest's disk/environment (if asked to).
+We provide packages in EPEL which cover RHEL/CentOS >= 5.  Use those
+or build from our source RPMs.

 
 

-This leaves open the question of which QEMU do we run, eg. qemu (the
-i386 emulator) or qemu-system-x86_64 or qemu-system-ppc64 or ...?

 
 

-Several factors influence the choice:
+Debian
+----------------------------------------------------------------------

 
 

-(a) The host architecture.
+libguestfs should build and run on Debian.  At the moment we don't
+provide Debian packages, and because of the appliance it's rather
+complicated to provide a package which could be accepted into the
+Debian repositories.  Want to help?  Please contact us.

 
 

-(b) The guest architecture.

 
 

-(c) What kernel(s) we find at runtime.
+qemu
+----------------------------------------------------------------------

 
 

-(d) What compiler(s) we find at configure time.
+By far the most common problem is with broken or incompatible
+qemu releases.

 
 

-(e) In general, we would prefer to run a 32 bit kernel over a 64 bit
-kernel, because that reduces the amount of system memory we have to
-give to qemu significantly, and makes libguestfs smaller, faster and
-use less memory.
+First of all, you need qemu >= 0.10.4, which contains a vmchannel
+implementation.  There are several, conflicting, incompatible things
+called 'vmchannel' which at one time or another have been added or
+proposed for qemu/KVM.  The _only_ one we support is this one:

 
 

-For example, if (a) the host is x86-64, then it might be running a
-mixture of (b) i386 and x86-64 guests.  Disk formats are stable, even
-across 32 and 64 bit and endianness changes, so it doesn't really
-matter what kernel we use if we just want to access files in the
-guest.  In the absence of any other factors, we would choose an i386
-kernel and run it in plain 'qemu', because that would use the least
-amount of memory.
+  http://lists.gnu.org/archive/html/qemu-devel/2009-02/msg01042.html

 
 

-But if we wanted to enable the feature of running a guest program in
-an x86-64 guest, then we have to run an x86-64 kernel and
-qemu-system-x86_64 (an i386 kernel can't run 64 bit programs).  The
-same applies if we didn't find a 32 bit kernel at runtime, or if we
-couldn't run "gcc -m32" at configure time (because we can't compile
-the daemon).
+Secondly, different versions of qemu have problems booting the
+appliance for different reasons.  This varies between versions of
+qemu, and Linux distributions which add their own patches.

 
 

-SO: to enable maximum features on 64 bit architectures:
+If you find a problem, you could try using your own qemu built from
+source (qemu is very easy to build from source), with a 'qemu
+wrapper'.  Qemu wrappers are described in the guestfs(3) manpage.

 
 

-(1) Ensure that "gcc -m32" can create usable binaries.

 
 

-(2) Provide 32 and 64 bit kernels binaries at runtime.
+Note on using KVM
+----------------------------------------------------------------------

 
 

-If you have a really weird environment, eg. you want to run programs
-inside PPC64 guests on your MIPS machine, then:
+By default the configure script will look for qemu-kvm (KVM support).
+You will need a reasonably recent processor for this to work.  KVM is
+much faster than using plain Qemu.

 
 

-(3) Provide gcc cross-compiler and glibc for each architecture, and
-cross-compile the daemon and NFS server:
+You may also need to enable KVM support for non-root users, by following
+these instructions:

 
 

-  mkdir daemon/build-ppc64
-  pushd daemon/build-ppc64
-  ../configure --host=ppc64-gnu-linux
-  make
-  popd
+  http://www.linux-kvm.org/page/FAQ#How_can_I_use_kvm_with_a_non-privileged_user.3F
+
+On some systems, this will work too:
+
+  chmod o+rw /dev/kvm
+
+On some systems, the chmod will not survive a reboot, and you will
+need to make edits to the udev configuration.
+
+
+Notes on cross-architecture support
+----------------------------------------------------------------------
+
+At the moment we basically don't support cross-architecture or
+32-on-64.  This limits what is possible for some guests.  Filesystem
+operations and FTP export will work fine, but running commands in
+guests may not be possible.
+
+To enable this requires work for cross-architecture and 32-on-64
+support in febootstrap, fakeroot and fakechroot.
+
+The daemon/ directory contains its own configure script.  This is so
+that in future we will be able to cross-compile the daemon.
+
+
+Mirroring tip
+----------------------------------------------------------------------
+
+On my machines I can usually rebuild the appliance in around 3
+minutes.  If it takes much longer for you, use a local Fedora mirror
+or squid.
+
+To use squid to cache yum downloads, read this first:
+https://lists.dulug.duke.edu/pipermail/yum/2006-August/009041.html
+(In brief, because yum chooses random mirrors each time, squid doesn't
+work very well with default yum configuration.  To get around this,
+choose a Fedora mirror which is close to you, set this with
+'./configure --with-mirror=[...]', and then proxy the whole lot
+through squid by setting http_proxy environment variable).
+
+You will also need to substantially increase the squid configuration
+limits:
+http://fedoraproject.org/wiki/Using_Mock_to_test_package_builds#Using_Squid_to_Speed_Up_Mock_package_downloads
+
+
+Porting to other Linux distros / non-Linux
+----------------------------------------------------------------------
+
+libguestfs itself should be fairly portable to other Linux
+distributions.  Non-Linux ports are trickier, but we will accept
+patches if they aren't too invasive.
+
+The main porting issues are with the dependencies needed to build the
+appliance.  You will need to find or port the following packages
+first:
+
+ - fakeroot
+ - fakechroot
+ - python
+ - rpm-python    http://www.rpm.org/
+ - yum           http://yum.baseurl.org/
+ - febootstrap   http://et.redhat.com/~rjones/febootstrap/

 
 
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 Copyright and license information