resolv.conf being overwritten

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX1
1

Something is overwriting /etc/resolv.conf with nvidia specific nameservers on the new build with 16.04 from the 2.3 Jetpack.

cat /etc/resolv.conf
domain nvidia.com
search nvidia.com
nameserver 10.24.4.101
nameserver 10.24.4.102
nameserver 10.25.20.252
nameserver 172.16.136.26

In 14.04, I was able to manually modify /etc/resolv.conf and it would stick after reboots, but now something else is overwriting resolv.conf each time the system is restarted. Some quick google searches suggest that resolvconf is responsible for overwriting this, but it doesn’t even appear to be installed. Some help would be appreciated as I am currently unable to resolve any dns addresses (but I can ping 8.8.8.8 and get responses just fine).

My /etc/network/interfaces is setup as (which worked fine on 14.04 - Jetpacks 2.2 and below):

[ubuntu@tegra-ubuntu:~] >>> cat /etc/network/interfaces
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 192.168.1.100
netmask 255.255.255.0

auto wlan0
iface wlan0 inet static
address 192.168.88.101
netmask 255.255.255.0
gateway 192.168.88.1
wpa-ssid xxx
wpa-psk xxx

dns-nameservers 8.8.8.8

2

This is one I’ve never figured out, but DHCP should be writing that file, which in turn means the entries are generated by the DHCP server itself. The question is whether you are using a router, or if DHCP is being served by your host? At some point I ended up just creating “/etc/ALT-resolv.conf”, and scripting the overwrite of resolv.conf with this at each boot.

3

I’m using a router, so there’s no way that the router dhcp is generating those nameservers. Seems like these are some legacy internal ips leftover from Nvidia dev work (can’t ping them). Would be nice to figure out where they are being generated from.

In the mean time, overwriting the resolv.conf file after boot and then ifdown/ifup the interfaces fixes things as a temp work around.

4

I believe this is coming from /boot/initrd

As root:

cd /root
cp /boot/initrd ./initrd.gz
gzip -d initrd.gz
mkdir initDisk
cd initDisk
cpio -i <…/initrd

vim etc/resolv.conf # make your changes here

find . | cpio --create --format=‘newc’ >…/newInitrd
cd …/
gzip newInitrd

mv /boot/initrd /boot/initrd_original
cp newInitrd.gz /boot/initrd