[CentOS] NetworkManager and /etc/resolv.conf

Sat Nov 17 14:43:46 UTC 2018
Alice Wonder <alice at domblogger.net>

CentOS 7.5 image running on linode.

unbound running on localhost.

Have to use a cron job once a minute to keep /etc/resolv.conf using the 
localhost for name resolution - whenever NetworkManager gets restarted 
(usually only a system boot) it gets over-written.

It seems every distro has a different way of preventing NetworkManager 
from replacing that file.

I found instructions for Fedora that said create 
/etc/NetworkManager/conf.d/no-dns.conf containing

[main]
dns=none

That doesn't seem to have any effect.

Poking around, I find a file on boot seems to be created called

/var/run/NetworkManager/resolv.conf

It has most of the contents of what ends up in /etc/resolv.conf - except 
w/o the last line, which just reads rotate in generated /etc/resolv.conf.

It says it's generated by NetworkManager (both /etc/resolv.conf and the 
one in /var/run/NetworkManager) but neither are specific enough to 
indicate what is causing them to be created so I can turn it off.

Anyone know how to tell NetworkManager to just not create that file?

Using a cron job to overwrite it once a minute works but there must be a 
proper way.

I really wish KISS was a design goal when designing system configuration.