Dumps proper lvcreate, mkfs and mkswap commands for cloning the filesystem layout of Xen guests

xen-lvm-dump-partitions

#!/usr/bin/env python
import os
import re
import sys
import shlex
import subprocess

# clone filesystem layout of Xen guests

# TODO:
# - don't hardcode target volume group; here: vg1
# - don't hardcode target filesystem type; here: ext3

def include(filename):
    if os.path.exists(filename):
        execfile(filename)
        return locals()

def run(command):
    cmd = shlex.split(command)
    proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    out, err = proc.communicate()
    return out

def lvdisplay_get_size(payload):
    m = re.search('LV Size\s+(.+)$', payload, re.MULTILINE)
    return m.group(1).replace(' ', '')

def main():
    configfile = sys.argv[1]
    config = include(configfile)
    #print config['disk']
    for disk in config['disk']:
        device = disk.split(':')[1].split(',')[0]
        #print device,
        size = lvdisplay_get_size(run('lvdisplay %s' % device))
        #print size
        device_basename = os.path.basename(device)

        lvcreate = "lvcreate -L '%s' -n %s vg1" % (size, device_basename)
        print lvcreate

        device_real = '/dev/vg1/%s' % device_basename
        mkfs = 'mkfs.ext3 %s' % device_real
        if 'swap' in device_basename:
            mkfs = 'mkswap %s' % device_real
        print mkfs



if __name__ == '__main__':
    main()