How to add additional IP to new interface on ubuntu 18.04? [closed]

Question

I have an ubuntu 18.04 VPS with 2 additional IPs, this is the config file I'm using which config all IPs on ens3:

network:
  version: 2
  renderer: networkd
  ethernets:
    ens3:
      dhcp4: no
      addresses: [a.a.a.a/23,b.b.b.b/23,c.c.c.c/23]
      gateway4: d.d.d.d
      nameservers:
        addresses: [108.61.10.10]
      routes:
      - to: 169.254.0.0/16
        via: d.d.d.d
        metric: 100

I want b.b.b.b and c.c.c.c to be on a different interface (like ens4), how should I change the config file?

This didn't help me: netplan config for two network interfaces no new interface in the output of "ifconfig -a" even after reboot

By the way, my vps is from vultr.com

Answer 1

Not sure i understand the question... I'd say:

ethernets:
ens3:
  dhcp4: no
  addresses: [a.a.a.a/23,c.c.c.c/23]
  gateway4: d.d.d.d
  nameservers:
    addresses: [108.61.10.10]
  routes:
  - to: 169.254.0.0/16
    via: d.d.d.d
    metric: 100
ens4:
     dhcp4: no
     addresses: [b.b.b.b/23]

?

ps. I think your:

  routes:
  - to: 169.254.0.0/16
    via: d.d.d.d

is not needed?, since it is set by default gateway already? ( unless more is going on ...)

Answer 2

What you're looking for could previously be done with the non-netplan system by doing subinterfaces (such as ens3.1, ens3.2, etc.)

Netplan does not support subinterfaces like this. The closes you would be able to get is what you have - multiple addresses on one individual ethernet device.

There's no way to spawn 'more' devices than actually exist on your system, so you can't reliably/sanely create "new interfaces" which don't actually exist anywhere. Not without setting up bridges and then virtual ethernet interfaces, but that's a bit beyond Netplan at that point, and probably overly complicated for what you need.