Re: [Libguestfs] febootstrap and zypper

On Fri, Nov 30, 2012 at 08:38:24PM +0100, Olaf Hering wrote: That all sounds good, so ignore what I said in the other reply. At boot time, febootstrap-supermin-helper takes files from the installed system. Except for files that could have changed (/etc files, or more specifically, files marked with %config). Those files come from the RPMs. We ensure the non-%config files exist on the host by using dependencies: http://pkgs.fedoraproject.org/cgit/libguestfs.git/tree/libguestfs.spec#n94 It's actually fairly easy to understand how it all works if you run febootstrap on a system like Fedora that already has a package handler. None of these commands need root, or will damage your system. $ cd /tmp; febootstrap --names bash febootstrap: warning: some host files are unreadable by non-root febootstrap: warning: get your distro to fix these files: /usr/sbin/build-locale-archive /usr/sbin/glibc_post_upgrade.x86_64 [after a few minutes, two files are created in the current directory] $ ls -l -rw-rw-r--. 1 rjones rjones 466258 Nov 30 19:56 hostfiles -rw-rw-r--. 1 rjones rjones 2732544 Nov 30 19:56 base.img $ wc -l hostfiles 17552 hostfiles $ grep /bin/bash hostfiles /usr/bin/bash /usr/bin/bashbug-64 $ cpio -itv < base.img [...] -rw-r--r-- 1 rjones rjones 158 Nov 30 19:56 etc/hosts -rw-r--r-- 1 rjones rjones 370 Nov 30 19:56 etc/hosts.allow -rw-r--r-- 1 rjones rjones 460 Nov 30 19:56 etc/hosts.deny -rw-r--r-- 1 rjones rjones 942 Nov 30 19:56 etc/inputrc -rw-r--r-- 1 rjones rjones 0 Nov 30 19:56 etc/ld.so.cache -rw-r--r-- 1 rjones rjones 28 Nov 30 19:56 etc/ld.so.conf drwxr-xr-x 2 rjones rjones 0 Nov 30 19:56 etc/ld.so.conf.d -rw-r--r-- 1 rjones rjones 0 Nov 30 19:56 etc/motd -rw-r--r-- 1 rjones rjones 1706 Nov 30 19:56 etc/nsswitch.conf drwxr-xr-x 2 rjones rjones 0 Nov 30 19:56 etc/opt -rw-r--r-- 1 rjones rjones 609 Nov 30 19:56 etc/passwd [...] 'base.img' contains the directory outline and configuration files, while 'hostfiles' is a list of files that will be pulled in from the host filesystem. 'base.img' + 'hostfiles' is what we call the "supermin appliance". To reconstruct a real appliance (as is done when libguestfs runs), do: $ mkdir output $ febootstrap-supermin-helper --format ext2 \ base.img hostfiles `uname -m` \ ouput/kernel output/initrd output/appliance $ ls -l output/ total 283112 -rw-r--r--. 1 rjones rjones 4294967296 Nov 30 20:00 appliance -rw-rw-r--. 1 rjones rjones 1220608 Nov 30 20:00 initrd lrwxrwxrwx. 1 rjones rjones 33 Nov 30 20:00 kernel -> /boot/vmlinuz-3.6.2-2.fc18.x86_64 And that's all there is to it. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://et.redhat.com/~rjones/virt-top