X-Git-Url: http://git.annexia.org/?p=libguestfs.git;a=blobdiff_plain;f=README;h=d56d21ee77e9edf458320491b7266967c139f109;hp=88fca7d3064839f2b88783c71ea71ef827bebf58;hb=bf2b08560f649c22152e4138531ad0b46b4ad1b3;hpb=7baf58278b620504d67acd01d3d992603fcd3b70 diff --git a/README b/README index 88fca7d..d56d21e 100644 --- a/README +++ b/README @@ -19,10 +19,17 @@ 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). -For discussion please use the fedora-virt mailing list: +Libguestfs was written by Richard W.M. Jones (rjones@redhat.com) and +hacked on by lots of other people. For discussion, development, +patches, etc. please use the mailing list: - https://www.redhat.com/mailman/listinfo/fedora-virt + http://www.redhat.com/mailman/listinfo/libguestfs + + +Home page +---------------------------------------------------------------------- + + http://libguestfs.org/ Requirements @@ -31,7 +38,7 @@ Requirements - recent QEMU >= 0.10 with vmchannel support http://lists.gnu.org/archive/html/qemu-devel/2009-02/msg01042.html -- febootstrap >= 2.0 +- febootstrap >= 2.3 - fakeroot @@ -67,6 +74,11 @@ bindings - (Optional) GHC if you want to build the Haskell bindings +- (Optional) Perl XML::XPath, Sys::Virt modules (for libvirt support +in virt-inspector). + +- (Optional, but highly recommended) perl-libintl for translating perl code. + Running ./configure will check you have all the requirements installed on your machine. @@ -114,10 +126,17 @@ or build from our source RPMs. Debian ---------------------------------------------------------------------- -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. +libguestfs is now built as a package in Debian by Guido Gunther and +the other Debian libvirt maintainers. See: + +http://wiki.debian.org/Teams/DebianLibvirtTeam#Packages + +You can build for Debian in two different ways, either building a +Fedora-based appliance using febootstrap, yum, rpm, fakeroot, +fakechroot (all packaged in Debian). However the recommended way is +to build a Debian-based appliance using debootstrap and debirf. + +Both ways are supported by the configure script. qemu @@ -162,6 +181,62 @@ On some systems, the chmod will not survive a reboot, and you will need to make edits to the udev configuration. +Supermin appliance +---------------------------------------------------------------------- + +If you configure with --enable-supermin then we will build a supermin +appliance (supermin = super-minimized). This is a very specialized +appliance which is built on-the-fly at runtime (specifically, when you +call guestfs_launch). + +The normal appliance is a self-contained Linux operating system, based +on the Fedora/RHEL/CentOS Linux distro. So it contains a complete +copy of all the libraries and programs needed, like kernel, libc, +bash, coreutils etc etc. + +The supermin appliance removes the kernel and all the executable +libraries and programs from the appliance. That just leaves a +skeleton of config files and some data files, which is obviously +massively smaller than the normal appliance. At runtime we rebuild +the appliance on-the-fly from the libraries and programs on the host +(eg. pulling in the real /lib/libc.so, the real /bin/bash etc.) + +Although this process of rebuilding the appliance each time sounds +slow, it turns out to be faster than using the prebuilt appliance. +(Most of the saving comes from not compressing the appliance - it +transpires that decompressing the appliance is the slowest part of the +whole boot sequence). On my machine, a new appliance can be built in +under a fifth of a second, and the boot time is several seconds +shorter. + +The big advantage of the supermin appliance for distributions like +Fedora is that it gets security fixes automatically from the host, so +there is no need to rebuild the whole of libguestfs for a security +update in some underlying library. + +There are several DISADVANTAGES: + +It won't work at all except in very narrow, controlled cases like the +Fedora packaging case. We control the dependencies of the libguestfs +RPM tightly to ensure that the required binaries are actually present +on the host. + +Furthermore there are certain unlikely changes in the packages on the +host which could break a supermin appliance, eg. an updated library +which depends on an additional data file. + +Also supermin appliances are subjected to changes in the host kernel +which might break compatibility with qemu -- these are, of course, +real bugs in any case. + +Lastly, supermin appliances really can't be moved between branches of +distributions (eg. built on Fedora 12 and moved to Fedora 10) because +they are not self-contained and they rely on certain libraries being +around. You shouldn't do this anyway. + +Use supermin appliances with caution. + + Notes on cross-architecture support ----------------------------------------------------------------------