UPDATE 2
Top posting because it is needed to apply the suggested solution.
Found on second answer to this question: Can netplan configured nameservers supersede (not merge with) the DHCP nameservers:
This has been fixed in the netplan repository on github, and will presumably make its way into Ubuntu at some point.
Two new options have been added, dhcp4-overrides and dhcp6-overrides. To ignore DNS servers from DHCP you would do something like
Anyone knows how to update netplan in Ubuntu 18.04?
Original question
I have an LXD vm with 2 network interfaces. If I use Ubuntu 16.04 (interfaces) I have 1 default gateway. If I use Ubuntu 18.04 (netplan) I have 2 default gateways. How can I get rid of the second gateway?
Ubuntu 16.04 configuration:
root@servizi:/etc/network/interfaces.d# ls -lha
total 3.5K
drwxr-xr-x 2 root root 4 Jul 31 2017 .
drwxr-xr-x 7 root root 8 Jul 12 2017 ..
-rw-r--r-- 1 root root 367 Jul 30 2017 50-cloud-init.cfg
-rw-r--r-- 1 root root 97 Jul 31 2017 60-locale.cfg
root@servizi:/etc/network/interfaces.d# cat 50-cloud-init.cfg
# This file is generated from information provided by
# the datasource. Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp
root@servizi:/etc/network/interfaces.d# cat 60-locale.cfg
auto eth1
iface eth1 inet dhcp
up route add -net 192.168.99.0 netmask 255.255.255.0 gw 10.0.1.1
root@servizi:/etc/network/interfaces.d# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.220.90.1 0.0.0.0 UG 0 0 0 eth0
10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
10.220.90.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.99.0 10.0.1.1 255.255.255.0 UG 0 0 0 eth1
root@servizi:/etc/network/interfaces.d#
Ubuntu 18.04 configuration
root@servizi2:/etc/netplan# ls -lh
total 2.0K
-rw-r--r-- 1 root root 381 Jan 24 17:30 50-cloud-init.yaml
-rw-r--r-- 1 root root 177 Feb 1 20:25 60-locale.yaml
root@servizi2:/etc/netplan# cat 50-cloud-init.yaml
# This file is generated from information provided by
# the datasource. Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
version: 2
ethernets:
eth0:
dhcp4: true
root@servizi2:/etc/netplan# cat 60-locale.yaml
# seconda scheda
network:
version: 2
ethernets:
eth1:
dhcp4: true
routes:
- to: 192.168.99.0/24
via: 10.0.1.1
root@servizi2:/etc/netplan# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.220.90.1 0.0.0.0 UG 100 0 0 eth0
0.0.0.0 10.0.1.1 0.0.0.0 UG 100 0 0 eth1
10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
10.0.1.1 0.0.0.0 255.255.255.255 UH 100 0 0 eth1
10.220.90.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
10.220.90.1 0.0.0.0 255.255.255.255 UH 100 0 0 eth0
root@servizi2:/etc/netplan#
UPDATE
Tried what @slangasek suggested and the second file is now:
root@servizi2:/etc/netplan# cat 60-locale.yaml
# seconda scheda
network:
version: 2
ethernets:
eth1:
dhcp4: true
dhcp4-overrides:
use-routes: false
routes:
- to: 192.168.99.0/24
via: 10.0.1.1
But netplan try gives the error "unknown key dhcp4-overrides"
root@servizi2:/etc/netplan# netplan try
Error in network definition /etc/netplan/60-locale.yaml line 5 column 12: unknown key dhcp4-overrides
An error occurred: the configuration could not be generated
Reverting.
root@servizi2:/etc/netplan#
Wha can I do?
It appears you have a default route on both eth0 and eth1 that is coming from dhcp; and you want to use only the default route through eth0.
To ignore the default route provided by your dhcp server, you would need to use
dhcp4-overrides, like so:This option is only supported in netplan 0.95 and later, which is currently available in Ubuntu 18.04 LTS and later releases.
and