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33.9. Generating a new unique MAC address

In some case you will need to generate a new and unique MAC address for a guest. There is no command line tool available to generate a new MAC address at the time of writing. The script provided below can generate a new MAC address for your guests. Save the script to your guest as macgen.py. Now from that directory you can run the script using ./macgen.py and it will generate a new MAC address. A sample output would look like the following: 
$ ./macgen.py 
00:16:3e:20:b0:11
	
#!/usr/bin/python
# macgen.py script to generate a MAC address for guests on Xen
#
import random
#
def randomMAC():
	mac = [ 0x00, 0x16, 0x3e,
		random.randint(0x00, 0x7f),
		random.randint(0x00, 0xff),
		random.randint(0x00, 0xff) ]
	return ':'.join(map(lambda x: "%02x" % x, mac))
#
print randomMAC()
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Another method to generate a new MAC for your guest

You can also use the built-in modules of python-virtinst to generate a new MAC address and UUID for use in a guest configuration file: 

# echo  'import virtinst.util ; print\
 virtinst.util.uuidToString(virtinst.util.randomUUID())' | python
# echo  'import virtinst.util ; print virtinst.util.randomMAC()' | python
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The script above can also be implemented as a script file as seen below. 
#!/usr/bin/env python
#  -*- mode: python; -*-
print ""
print "New UUID:"
import virtinst.util ; print virtinst.util.uuidToString(virtinst.util.randomUUID())
print "New MAC:"
import virtinst.util ; print virtinst.util.randomMAC()
print ""
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