Getting a unique hardware ID with Python

I have a process that requires me to identify different machines, and I'm not sure what's the best way to do it. I do not want to save that ID on a text file or something, but I want to generate it from hardware every time I need it (in case the text with the ID gets deleted or something)

I've checked UUID, and it seems ok but I'm not sure. I've taken a look at uuid.getNode(), but I have 2 problems with it:

1. One part says "If all attempts to obtain the hardware address fail, we choose a random 48-bit number with its eighth bit set to 1 as recommended in RFC 4122", which means that I may get a different unique on some systems for some reason - is there a way to identify which time it failed and generate something else?

2. another part says: " “Hardware address” means the MAC address of a network interface, and on a machine with multiple network interfaces the MAC address of any one of them may be returned.", which means if i have 2 different network adapters, each call I may get any one of them? that's not good for me.

If you have a better way of obtaining a unique ID for a machine, that I can generate each time and won't have to worry about deletion of it or something - I'd be glad to hear it. all of my attempts to find something have failed. Thanks.

You could use dmidecode.

Linux:

import subprocess

def get_id():
    return subprocess.Popen('hal-get-property --udi /org/freedesktop/Hal/devices/computer --key system.hardware.uuid'.split())

Windows:
NOTE: Requires dmidecode for Windows

import subprocess

def get_id():
    return subprocess.Popen('dmidecode.exe -s system-uuid'.split())

Cross-platform:
NOTE: Requires dmidecode for Windows

import subprocess
import os

def get_id():
    if 'nt' in os.name:
        return subprocess.Popen('dmidecode.exe -s system-uuid'.split())
    else:
        return subprocess.Popen('hal-get-property --udi /org/freedesktop/Hal/devices/computer --key system.hardware.uuid'.split())