resolv.conf questions

[Ralf Mardorf]

On Tue, 6 Aug 2019 13:22:19 +0000, Mike Marchywka wrote:
>I think there are comment somewhere that you can replcae that( IIRC 
>a symbolic link, [snip] with an actual file

IIRC I needed to do this, to use systemd-nspawn without the '--boot'
option [1], but apart from such an unusual case the link against run/
shouldn't matter and the content of the file likely gets automatically
overwritten [2], if it's a link to a file or a file.

[1]
[rocketmouse at archlinux ~]$ head -2 /mnt/moonstudio/etc/os-release
NAME="Ubuntu"
VERSION="16.04.6 LTS (Xenial Xerus)"
[rocketmouse at archlinux ~]$ ls -l /mnt/moonstudio/etc/resolv.conf
-rw-r--r-- 1 root root 94 Aug  5 23:08 /mnt/moonstudio/etc/resolv.conf
[rocketmouse at archlinux ~]$ cat /mnt/moonstudio/etc/resolv.conf
# Generated by resolvconf
domain localdomain
nameserver 192.168.1.1
nameserver fe80::1%enp3s0
[rocketmouse at archlinux ~]$ head -2 /etc/os-release
NAME="Arch Linux"
PRETTY_NAME="Arch Linux"
[rocketmouse at archlinux ~]$ ls -l /etc/resolv.conf
-rw-r--r-- 1 root root 94 Aug  5 23:08 /etc/resolv.conf
[rocketmouse at archlinux ~]$ cat /etc/resolv.conf
# Generated by resolvconf
domain localdomain
nameserver 192.168.1.1
nameserver fe80::1%enp3s0

[2]
"Normally  the  resolvconf  program is run only by network interface
configuration programs such as ifup(8),  ifdown,  NetworkManager(8),
dhclient(8),  and  pppd(8);  and  by  local nameservers  such  as
dnsmasq(8).  These programs obtain nameserver information from some
source and push it to resolvconf."
- http://manpages.ubuntu.com/manpages/xenial/man8/resolvconf.8.html

Let alone that Colin already posted
"# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
 #     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN"

So even if it's not in run/, a tmpfs that gets deleted at shutdown, the
content will be overwritten.