X-Git-Url: http://git.annexia.org/?p=libguestfs.git;a=blobdiff_plain;f=README;h=be4953d5c4363edde53f9e7d7a330cf35829c95f;hp=9306b5cce08c584cd28bb8ddd1cbb54462c06144;hb=dc8e4b057ecd3984d7c27c8e;hpb=407caabfd04a8bb6338a7fcf4f46d85d75e709df diff --git a/README b/README index 9306b5c..be4953d 100644 --- a/README +++ b/README @@ -1,174 +1,216 @@ -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: -virt-p2v), performing partial backups, performing partial guest -clones, cloning guests and changing registry/UUID/hostname info, and -much else besides. +Libguestfs is tools and a library for accessing and modifying guest +disk images. For more information see the home page: -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. + http://libguestfs.org/ -libguestfs provides ways to enumerate guest storage (eg. partitions, -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). +For discussion, development, patches, etc. please use the mailing +list: -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 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 + http://www.redhat.com/mailman/listinfo/libguestfs Requirements ---------------------------------------------------------------------- -- nfs-utils source, unpacked - http://download.sourceforge.net/nfs +- recent QEMU >= 0.13 with virtio-serial support -- Recent QEMU with vmchannel support +- kernel >= 2.6.34 with virtio-serial support enabled. virtio-block + and virtio-serial support are not required but highly recommended. -- Compiled Linux kernels for 32 and/or 64 bit (see note below). +- febootstrap >= 3.0 (recommended >= 3.3) + *NB*: febootstrap 2.x WILL NOT WORK + febootstrap 3.x is distro-independent, and is required on + Debian and other distros too -- mkinitrd +- XDR, rpcgen (on Linux these are provided by glibc) -- cpio +- pcre (Perl Compatible Regular Expressions C library) (optional) -- XDR, rpcgen +- libmagic (the library that corresponds to the 'file' command) (optional) -- If you are running a 64 bit or non-x86 machine, see note below. +- libvirt (optional) -We don't support initramfs at the moment. Patches gratefully -received. +- libxml2 (optional) -Running ./configure will check you have all the requirements installed -on your machine. +- Augeas (http://augeas.net/) (optional) +- gperf -Building ----------------------------------------------------------------------- +- squashfs-tools (mksquashfs only) -Unpack nfs-utils source into a directory somewhere, then create a -symlink daemon/nfs-utils to where you unpacked it. For example: +- genisoimage / mkisofs - pushd daemon - tar zxf /path/to/nfs-utils-1.1.4.tar.gz - ln -s nfs-utils-1.1.4 nfs-utils - popd +- hivex >= 1.2.1 (http://libguestfs.org/download) -For nfs-utils 1.1.4, you may find that the patch -(nfs-utils-1.1.4-build.patch) helps. +- (Optional) Berkeley DB 'db_dump' and 'db_load' utilities + (db4-utils or db4.X-util or similar) -Then make the library and shell tools: +- (Optional) FUSE to build the FUSE module - ./configure - make +- perldoc (pod2man, pod2text, pod2html) to generate the manual pages + and other documentation. -Make the daemon and NFS server: - mkdir daemon/build - pushd daemon/build - ../configure [--disable-nfsv4 --disable-gss] - make - popd +- (Optional) Readline to have nicer command-line editing in guestfish. -For 64 bit you'll probably want to build the 32 bit daemon and NFS -server too: +- (Optional) xmllint to validate virt-inspector RELAX NG schema - mkdir daemon/build-32 - pushd daemon/build-32 - ../configure --enable-32bit [--disable-nfsv4 --disable-gss] - make - popd +- (Optional) OCaml if you want to rebuild the generated files, and + also to build the OCaml bindings + +- (Optional) Perl if you want to build the perl bindings + +- (Optional) Python if you want to build the python bindings + +- (Optional) Ruby, rake if you want to build the ruby bindings + +- (Optional) Java, JNI, jpackage-utils if you want to build the java +bindings -For complex cross-architecture environments, you may want to build -other versions of the daemon and NFS server as well. See the note -below. +- (Optional) GHC if you want to build the Haskell bindings + +- (Optional) Perl Sys::Virt module. + +- (Optional) Perl Win::Hivex module. + +- (Optional) Perl Pod::Usage module. + +- (Optional) Perl Test::More module (from perl Test::Simple). + +- (Optional) Perl String::ShellQuote module. + +- (Optional, but highly recommended) perl-libintl for translating perl code. + +- po4a for translating manpages and POD files. + This is optional when compiling from the tarball, but mandatory + if you compile from git. + +- (Optional) PHP, phpize if you want to build the PHP bindings + +Running ./configure will check you have all the requirements installed +on your machine. + + +Building +---------------------------------------------------------------------- + +Then make the daemon, library and root filesystem: + + ./configure + make 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 - pushd daemon/build - make install - popd - # Repeat for each daemon/build* directory you made above. +qemu +---------------------------------------------------------------------- + +By far the most common problem is with broken or incompatible +qemu releases. + +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. + +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. + + +Note on using KVM +---------------------------------------------------------------------- + +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. + +You may also need to enable KVM support for non-root users, by following +these instructions: + + 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. -Note on 64 bit and non-x86 architectures + +vmchannel ---------------------------------------------------------------------- -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). +Previous versions of libguestfs required something called "vmchannel". +Vmchannel is a special device given to virtual machines which allows +them to communicate in some way with the host, often (but not always) +without using a traditional network device. In reality, there is no +one thing called "vmchannel". This idea has been reimplemented +several times under the name vmchannel, and other hypervisors have +their own incompatible implementation(s) too. + +In libguestfs <= 1.0.71, we required a specific vmchannel which is +properly known as "guestfwd" and has been upstream in qemu since here: -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 ...? + http://lists.gnu.org/archive/html/qemu-devel/2009-02/msg01042.html -Several factors influence the choice: +In libguestfs >= 1.0.71 we don't require any vmchannel implementation, +as long as qemu has been compiled with support for SLIRP (user mode +networking, or "-net user"), which is almost always the case. -(a) The host architecture. +In libguestfs >= 1.5.4 we switched again to using qemu's virtio-serial +and removed all the other vmchannels and the SLIRP channel. -(b) The guest architecture. -(c) What kernel(s) we find at runtime. +Supermin appliance +---------------------------------------------------------------------- -(d) What compiler(s) we find at configure time. +In libguestfs >= 1.7.19 the supermin appliance is the default and only +supported form of appliance. For more information see febootstrap +(http://people.redhat.com/~rjones/febootstrap/). -(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. -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. +Mirroring tip +---------------------------------------------------------------------- -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). +On my machines I can usually rebuild the appliance in around 3 +minutes. If it takes much longer for you, use a local distro mirror +or squid. -SO: to enable maximum features on 64 bit architectures: +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). -(1) Ensure that "gcc -m32" can create usable binaries. +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 -(2) Provide 32 and 64 bit kernels binaries at runtime. -If you have a really weird environment, eg. you want to run programs -inside PPC64 guests on your MIPS machine, then: +Porting to other Linux distros / non-Linux +---------------------------------------------------------------------- -(3) Provide gcc cross-compiler and glibc for each architecture, and -cross-compile the daemon and NFS server: +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. - mkdir daemon/build-ppc64 - pushd daemon/build-ppc64 - ../configure --host=ppc64-gnu-linux - make - popd +The main porting issues are with the dependencies needed to build the +appliance. You will need to port the febootstrap first +(http://people.redhat.com/~rjones/febootstrap/). Copyright and license information ---------------------------------------------------------------------- -Copyright (C) 2009 Red Hat Inc. +Copyright (C) 2009-2010 Red Hat Inc. The library is distributed under the LGPLv2+. The programs are distributed under the GPLv2+. Please see the files COPYING and