libguestfs 0.8, now with fewer bugs :-)

I released libguestfs 0.8 yesterday, the library for accessing virtual machines. This version fixes a large number of bugs, because I wrote a test suite which sends several hundred commands through the library and verifies the results. Took a couple of days to fix all the bugs this found …

Here are some interesting things you can do with guestfish.

1: Just find out what’s in a virtual machine:

$ guestfish -a RHEL52PV32.img run : list-devices
/dev/sda

$ guestfish -a RHEL52PV32.img run : list-partitions
/dev/sda1
/dev/sda2

$ guestfish -a RHEL52PV32.img run : lvs
/dev/VolGroup00/LogVol00
/dev/VolGroup00/LogVol01

2: Make virtual machine filesystems containing partitions, LVM, filesystems and whatever else you want:

$ guestfish
Welcome to guestfish, the libguestfs filesystem interactive shell for
editing virtual machine filesystems.

Type: 'help' for help with commands
      'quit' to quit the shell

><fs> alloc /tmp/test 500M
><fs> run
><fs> pvcreate /dev/sda
><fs> vgcreate VG /dev/sda
><fs> vgs
VG
><fs> lvcreate LV VG 250
><fs> lvs
/dev/VG/LV
><fs> mkfs ext3 /dev/VG/LV
><fs> mount /dev/VG/LV /
><fs> touch /myfile
><fs> ll /
total 13
drwxr-xr-x  3 root root  1024 Apr 12 17:19 .
drwxr-xr-x 18 root root     0 Apr 12 17:15 ..
drwx------  2 root root 12288 Apr 12 17:19 lost+found
-rw-r--r--  1 root root     0 Apr 12 17:19 myfile
><fs> sync
><fs> quit
$ ll /tmp/test
-rw-rw-r--. 1 rjones rjones 524288000 2009-04-12 22:19 /tmp/test
$ file /tmp/test
/tmp/test: LVM2 (Linux Logical Volume Manager) , UUID: bhL0DP0rySspzviDKHN7TZABBcfTWuo

3: Use Augeas to edit configuration files:

$ guestfish -a RHEL52PV32.img -m /dev/VolGroup00/LogVol00
  
  Welcome to guestfish, the libguestfs filesystem interactive shell for
  editing virtual machine filesystems.
  
  Type: 'help' for help with commands
        'quit' to quit the shell
  
><fs> aug-init / 0
><fs> aug-match /augeas/*
/augeas/root
/augeas/save
/augeas/files
><fs> aug-match /files//error
><fs> aug-match /augeas//error
><fs> aug-match /augeas/root/*
><fs> aug-match /files/etc/*
/files/etc/ldap.conf
/files/etc/aliases
/files/etc/yum.repos.d
/files/etc/yum.conf
/files/etc/sysconfig
[etc]
><fs> aug-match /files/etc/hosts/*
/files/etc/hosts/comment[1]
/files/etc/hosts/comment[2]
/files/etc/hosts/1
/files/etc/hosts/2
><fs> cat /etc/hosts               
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1      	       localhost.localdomain localhost
::1		               localhost6.localdomain6 localhost6
><fs> aug-get /files/etc/hosts/comment[1]
Do not remove the following line, or various programs
><fs> help aug-insert
aug-insert - insert a sibling Augeas node
       aug-insert   
  
      Create a new sibling "label" for "path", inserting it into the tree
      before or after "path" (depending on the boolean flag "before").
  
      "path" must match exactly one existing node in the tree, and "label"
      must be a label, ie. not contain "/", "*" or end with a bracketed index
      "[N]".
  
><fs> aug-insert /files/etc/hosts/comment[2] comment false
><fs> aug-match /files/etc/hosts/*
/files/etc/hosts/comment[1]
/files/etc/hosts/comment[2]
/files/etc/hosts/comment[3]
/files/etc/hosts/1
/files/etc/hosts/2
><fs> aug-set /files/etc/hosts/comment[3] HELLO
><fs> aug-save
><fs> cat /etc/hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
# HELLO
127.0.0.1		localhost.localdomain localhost
::1			localhost6.localdomain6 localhost6

There are C, C++, shell, Perl and OCaml bindings for all of these calls, and you don’t need to be root to do any of it.