[CentOS] Static configuration: prevent /etc/resolv.conf from being overwritten on first reboot

Hi,

Here's something that's puzzling me.

Starting from a minimal installation of CentOS 7, network configuration is DHCP.

I'm launching nmtui to define a static configuration.

I'm providing the IP address as well as the gateway, but no DNS server.

I'm quitting nmtui and I'm editing /etc/resolv.conf to provide my DNS server:

# /etc/resolv.conf nameserver 192.168.0.254

I reboot my server, and I don't know why, but my /etc/resolv.conf has been overwritten:

# Generated by NetworkManager

So I edit this file again:

# /etc/resolv.conf nameserver 192.168.0.254

And starting from here, it works, meaning /etc/resolv.conf is not overwritten on subsequent reboots.

Q: how can I prevent /etc/resolv.conf from being overwritten on the initial reboot? I vaguely remember having to kill some process before editing it, but unfortunately I don't remember which one.

Cheers,

Niki