Comment 3 for bug 1704376

BTW, looking at the raw pastebins, I noticed something funny:
https://pastebin.canonical.com/193850/plain/

If you have the wrong character encoding, those show up as:
iface lo inet loopback
    dns-nameservers 8.8.8.8
    dns-search maas

I wonder if the actual problem is that your editor was inserting characters that aren't plain space (0x20) or plain tab (0x09).
From the looks of it, those are:
u'\xa0'
http://www.utf8-chartable.de/unicode-utf8-table.pl?start=128&number=128&utf8=string-literal&unicodeinhtml=hex

That is "Unicode Non-breaking Space", which is probably *not* accepted in a eth0.cfg.
Certainly it isn't a character that we had been supporting parsing. I'm a bit surprised that the configuration was working. (It could be that the python parser is doing a unicode regex \s and that handles non-ascii characters ok.)

Can you just replace the '\xa0' non-breaking-space characters with plain '\x20' spaces?
I don't know how that file is getting written. I'm guessing its some sort of generated template, and you ended up with '\xa0' in your template file.